16 September - IOBC-WPRS

IOBC / WPRS

Working Group „Integrated Plant Protection in Orchards“ Subgroup “Soft Fruits”

in cooperation with the

ISHS

Working Group „Integrated Fruit Production”

Proceedings of the Second Workshop on Integrated Production of Soft Fruits

at

Warszawa / Miedzeszyn, Poland

13 – 16 September, 1999

Edited by Dariusz Gajek & Fritz Polesny

IOBC wprs Bulletin Bulletin OILB srop Vol. 23 (11) 2000

The IOBC/WPRS Bulletin is published by the International Organization for Biological and Integrated Control of Noxious Animals and Plants, West Palearctic Regional Section (IOBC/WPRS) Le Bulletin OILB/SROP est publié par l‘Organisation Internationale de Lutte Biologique et Intégrée contre les Animaux et les Plantes Nuisibles, section Regionale Ouest Paléarctique (OILB/SROP) Copyright: IOBC/WPRS 2000

The Publication Commission of the IOBC/WPRS: Horst Bathon Federal Biological Research Center for Agriculture and Forestry (BBA) Institute for Biological Control Heinrichstr. 243 D-64287 Darmstadt (Germany) Tel +49 6151 407-225, Fax +49 6151 407-290 e-mail: [email protected]

Luc Tirry University of Gent Laboratory of Agrozoology Department of Crop Protection Coupure Links 653 B-9000 Gent (Belgium) Tel +32-9-2646152, Fax +32-9-2646239 e-mail: luc.tirry@ rug.ac.be

Address General Secretariat: INRA – Centre de Recherches de Dijon Laboratoire de recherches sur la Flore Pathogène dans le Sol 17, Rue Sully, BV 1540 F-21034 DIJON CEDEX France ISBN 92-9067-127-0

The meeting was sponsored by:

INTERNATIONAL ORGANIZATION FOR BIOLOGICAL AND INTEGRATED CONTROL OF NOXIOUS ANIMALS AND PLANTS,

West Palearctic Regional Section (IOBC/WPRS)

PRECOPTIC Co. Medical & Optical Instruments

BAYER Sp. z o. o., Warsaw, Poland

SUMI-AGRO Sp. z o. o. Warsaw, Poland

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Second Workshop on Integrated Production of Soft Fruits Warszawa / Miedzeszyn, Poland, September 13-16, 1999

PROGRAMME

SEPTEMBER, 13 (MONDAY)

Arrival and registration day

19.00 – 21.00 Welcome supper

SEPTEMBER, 14 (TUESDAY)

7.00 – 9.30 Breakfast

9.30 – 9.40 Welcome opening

Session I. Chair person: E.Niemczyk

9.40 – 10.00 F.Polesny An overview on the work and activities of IOBC orchard group and subgroups

10.00 – 10.20 E.Joerg and J.Cross The IOBC -Guidelines for Integrated Production of Soft Fruits

10.20 – 10.40 R.W.Olszak, B.Łabanowska, A.Bielenin, D.Gajek

Prospects of developping integrated methods of small fruit production in Poland

10.40 – 11.10 Coffee break

Session II. Chair person: R.W.Olszak

11.10 – 11.30 B.Łabanowska, A.Bielenin

The standard and the integrated strawberry production in Poland

11.30 – 11.50 V.Laugale Strawberry production in Latvia

11.50 – 12.10 J.Gwozdecki Cultivars of currants for integrated fruit production

12.10 – 12.30 Discussion and summarising of sessions I and II

12.30 – 14.30 Lunch (during break optical instruments will be presented by ‘Precoptic Co.’)

Session III. Chair person: A.Bielenin

14.30 – 14.50 T.Malinowski, S.Pluta, A.Kuras, E.Żurawicz

Evaluation of two methods of detection of blackcurrant reversion associated virus (BRAV)

14.50 – 15.10 E. Jörg, U. Harzer, W. Ollig

Integrated Approach for the Control of American Gooseberry Mildew

15.10 – 15.30 A.M.Berrie, Xn Xo, D.C.Itaris, C.M.Burgess

First results of testing a management system for strawberry Botrytis and powdery mildew

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15.30 – 15.50 R. Steffek, J. Altenburger

Occurrence and spread of strawberry anthracnose caused by Colletotrichum acutatum in Austrian strawberry fields – Experiences from laboratory, greenhouse and field

15.50 – 16.00 Discussion and summarising of session III


16.30 – 18.00 Poster session

1. Progress in breeding of blackcurrant (Ribes nigrum L.) for resistance to main fungal diseases at Research Institute of Pomology and Floriculture at Skierniewice, Poland - A.Broniarek-Niemiec, S.Pluta, A.Bielenin

2. Resistance of strawberry cultivars to fungal diseases - V.Laugale, I.Maroćko

3. Preliminary studies on resistance of some strawberry cultivars to spider mite Tetranychus urticae- V.Petrova, Z. Čudare, I. Šteinite, V.Laugale

4. Progress in selection of blackcurrant cultivars suitable for integrated mite management - D.Gajek, S.Pluta, E.Żurawicz

5. Side effect of fungicides used in Botrytis control on occurrence of leather rot of strawberry - A. Bielenin, B. Meszka

6. Occurrence and identification of strawberry green petal phytoplasma - M.Cieślińska, B.Zawadzka

7. Efficacy of Euparen 50 WP and Euparen M 50 WG in the control of grey mould Botrytis cinerea and reduction of the population of two-spotted spider mite Tetranychus urticae Koch. in strawberries - B.Meszka, B.H. Łabanowska, A.Bielenin

8. Usefulness of Mospilan 20 SP in integrated pest management of soft fruits - B. H.Łabanowska, D. Gajek, E. Niemczyk

9. Preliminary IPM program of blackcurrant crop for Poland - E.Niemczyk, B.Łabanowska, D.Gajek

10. Storage of soft fruits - W.Ollig, E.Joerg

11. Pesticide residues in soft fruits: strawberries, currants and raspberries (Monitoring 1997-98) - A.Nowacka

12. Consumer acceptance for soft fruits from integrated production - K.Zmarlicki

19.00 – 21.00 Supper

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SEPTEMBER, 15 (WEDNESDAY)


Session IV. Chair person: F. Polesny

9.30 – 9.50 D. Gajek, E. Niemczyk, M. Sekrecka

Effectiveness of different control methods of blackcurrant gall mite and their influence on populations of phytoseiid mites and two-spotted spider mite

9.50 – 10.10 E. Niemczyk Occurrence and effectiveness of predatory mites (Phytoseiidae) in controlling two-spotted spider mite (Tetranychus urticae Koch.) on black currant crop

10.10 – 10.30 S. Jaworski Occurrence of phytoseiid mites (Acari: Phytoseiidae) on blackcurrent plantations and in surrounding vegetation in southern Poland

10.30 – 10.40 Discussion and summarising of session IV


Session V. Chair person: E. Joerg

11.10 – 11.20 A.Shi Eriophyoid mites of blackberries and raspberries rubus spp.

11.20 – 11.40 J.V. Cross, P. Innocenzi, D. Hall

Investigations of pheromones of soft fruit pests

11.40 – 12.00 S. C. Gordon, J. A. Trefor Woodford

Aims and objectives of Reduced Application of Chemicals in European Raspberry Production (RACER) project

12.00 – 12.10 Discussion and summarising of sessions V

12.10 – 14.00 Lunch

14.00 – 19.00 Excursion to Botanical Garden in Powsin

19.00 – 22.00 Return to hotel ‘Boss’ and supper in Mountaineer’s Hut

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SEPTEMBER, 16 (THURSDAY)


Session VI. Chair person: J.V. Cross

9.30 – 9.50 H. Daugaard, P. Kryger Jensen, B. Loschenkohl

Minimised fungicide application using tunnel sprayer in strawberries – biological effects and practical experiences

9.50 – 10.10 G. Doruchowski, B. Łabanowska, A. Godyń, R. Hołownicki

Spray Application Techniques in Integrated Production of Soft Fruit

10.10 – 10.30 J.V. Cross Spray application in strawberry

10.30 – 10.40 J. Lisek Weed species on soft fruit plantations in Poland 10.40 – 10.50 J. Lisek Possibilities of efficient weed control in

Integrated Production of soft fruits 10.50 – 11.00 Discussion and summarising of session VI


11.30 – 12.30 E. Joerg Summarising discussion

12.30 – 14.30 Good bye lunch, departing to airport and Warsaw City Centre, leaving Poland

19.00 – 22.00 Supper (participants of the post conference tour)

SEPTEMBER, 17 (FRIDAY)

7.00 – 8.00 Breakfast and leaving hotel 'Boss'

Post conference trip

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List of participants

Name Address, e-mail, fax, telephone

Angela BERRIE

HRI East Malling, West Malling, Kent, ME 19 6 BJ, United Kingdom e-mail: [email protected] fax: 0044 1732 849067; tel.: 0044 1732 843 833

Anna BIELENIN

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Bacteriology and Mycology, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Agata BRONIAREK - NIEMIEC


Mirosława CIEŚLIŃSKA

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Virology, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Jerry CROSS

HRI East Malling, West Malling, Kent, ME 19 6 BJ, United Kingdom e-mail: [email protected] fax: 0044 1732 849067; tel.: 0044 1732 843 833

Holger DAUGAARD

Danish Inst. of Agricultural Sciences, Dep. of Fruit and Vegetables, Kirstinebjergvej 10, DK – 5792 Aarslev, Denmark e-mail: [email protected] fax: 0045 63904396; tel.: 0045 63904343

Annie DEMEYERE

Ministry of Agriculture, Gebouw Rhena, Heibeekplein 9 - 3e, verdieping B - 3500 Hasselt, Belgium fax: 0032 11 26 39 53; tel.: 0032 11 26 39 45

Grzegorz DORUCHOWSKI

Research Institute of Pomology and Floriculture, Department of Horticultural Engieering, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

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Dariusz GAJEK

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Biological Control of Orchard Pests, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Stuart GORDON

Scottish Crop Research Institute, Soft Fruit & Perential Crops Department Invergowrie, Dundee DD2 5DA, Scotland, United Kingdom e-mail: [email protected] fax: 0044 1382 562426; tel.: 0044 1382 562731

Józef GWOZDECKI

Research Institute of Pomology and Floriculture, Section of Small Fruits, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Caroline JANSSEN

Royal Research Station of Gorsem, Brede Akker 3, B-3800 Sint-Truiden, Belgium fax: 0032 (0) 11674318; tel.: 0032 (0) 11682019

Sebastian JAWORSKI

Warsaw Agricultural University, Department of Applied Entomology, Nowoursynowska 166, 02-787 Warszawa, Poland tel.: 0048 22 8434942

Erich JOERG

Landesanstalt für Pflanzenbau und Pflanzenschutz, Essenheimerstr. 144, D-55128 Mainz, Germany e-mail: [email protected] fax: 0049 6131 993080; tel.: 0049 6131 993020

Danuta KROPCZYŃSKA

Warsaw Agricultural University, Department of Applied Entomology, Nowoursynowska 166, 02-787 Warszawa, Poland e-mail: [email protected] tel.: 0048 22 8434942

Valda LAUGALE

Puzes DIS, Tukuma zaj., LV-3124, Latvia e-mail: [email protected] fax / tel.: 0031 81263

Jerzy LISEK

Research Institute of Pomology and Floriculture, Section of Small Fruits, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Barbara ŁABANOWSKA

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Entomology, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Tadeusz MALINOWSKI

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Virology, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

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Beata MESZKA


Edmund NIEMCZYK

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Biological Control of Orchard Pests, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Anna NOWACKA

Plant Protection Institute, Miczurina 20, 60-318 Poznań, Poland fax: 0048 618676301; tel.: 0048 618674841

Remigiusz OLSZAK

Research Institute of Pomology and Floriculture, Department of Plant Protection, Section of Entomology, Pomologiczna 18, 96-100 Skierniewice, Poland e-mail: [email protected] fax: 0048 46 8333228; tel.: 0048 46 8332021

Friedrich POLESNY

BFL, Inst.f.Phytomedizin, Spargelfeldstr. 191, A - 1220 Vienna, Austria e-mail: [email protected] fax: 0043 1 288165194; tel.: 0043 1 288165154

Aoxiang SHI

Warsaw Agricultural University, Department of Applied Entomology, Nowoursynowska 166, 02-787 Warszawa, Poland tel.: 0048 22 8434942

Robert STEFFEK

BFL, Inst.f.Phytomedizin, Spargelfeldstr. 191, A - 1220 Vienna, Austria e-mail: [email protected] fax: 0043 1 288165194; tel.: 0043 1 288165171

Ineta ŠTEINITE

National Botanical Garden, Miera str. 1, LV-2169, Latvia e-mail: [email protected] fax: 00371 2944735; tel.: 00371 2945467

Elżbieta TOPA

Olsztyn University of Agriculture and Technology, Department of Plant Protection, Prawocheńskiego 17, 10-722 Olsztyn- Kortowo, Poland e-mail: [email protected] fax: 004889273908

Helmut WEISS

LLK Steiermark, Hamerlingg. 3, A - 8010 Graz, Austria fax: 0043 316 8050 511; tel.: 0043 316 8050 503

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Table of Contents Program ...................................................................................................................................... i List of Participants .................................................................................................................... v Prospects of developping integrated methods of small fruit production in Poland Olszak, R.W., B. Łabanowska, A. Bielenin & D. Gajek ............................................................ 1 The standard and the integrated strawberry production in Poland Łabanowska, B. & A. Bielenin .................................................................................................. 7 Strawberry production in Latvia Laugale, V. ............................................................................................................................. 11 Cultivars of currants for integrated fruit production Gwozdecki, J. .......................................................................................................................... 17 Evaluation of two methods of detection of blackcurrant reversion-associated virus (BRAV) Malinowski, T., S. Pluta, A. Kuras & E. Żurawicz.................................................................. 21 Integrated approach for the control of American Gooseberry Mildew Jörg, E., U. Harzer & W. Ollig ............................................................................................... 25 A system for managing Botrytis and powdery mildew of strawberry: first results Berrie, A.M., D.C. Harris, Xianming Xu & C.M. Burgess...................................................... 35 Occurrence and spread of strawberry anthracnose caused by Colletotrichum acutatum in Austrian strawberry fields – experiences from laboratory, greenhouse and field Steffek, R. & J. Altenburger..................................................................................................... 41 Effectiveness of different methods of blackcurrant gall mite control (Cecidophyopsis ribis Westw.) and their influence on population of phytoseiid mites and two-spotted spider mite Gajek, D., E. Niemczyk & M. Sekrecka................................................................................... 47 Occurrence and effectiveness of predatory mites (Phytoseiidae) in controlling two-spotted spider mite (Tetranychus urticae Koch) on black currants Niemczyk, E. ........................................................................................................................... 53 Occurrence of phytoseiid mites (Acari Phytoseiidae) on blackcurrent plantations and in surrounding vegetation in southern Poland Jaworski, S. ............................................................................................................................ 57 Eriophyoid mites of blackberries and raspberries (Rubus spp.) Shi, A. ..................................................................................................................................... 63 Investigations of pheromones of soft fruit pests Cross, J.V., P. Innocenzi & D. Hall ........................................................................................ 67 Aims and objectives of reduced application of chemicals in European raspberry production (RACER) project Gordon, S.C. & J.A. Trefor Woodford .................................................................................... 73 Minimised fungicide application using tunnel sprayer in strawberries – biological effects and practical experiences Daugaard, H., P. Kryger Jensen & B. Løschenkohl ............................................................... 81

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Spray application techniques in Integrated Production of soft fruit Doruchowski, G., B. Łabanowska, A. Godyń & R. Hołownicki .............................................. 85 Improving strawberry spraying Cross, J.V., A.M. Berrie & R.A. Murray ................................................................................. 91 Weed species on soft fruit plantations in Poland Lisek, J. ................................................................................................................................... 99 Possibilities of efficient weed control in Integrated Production of soft fruits. Lisek, J. ................................................................................................................................. 103 Poster Progress in breeding of blackcurrant (Ribes nigrum L.) for resistance to main fungal diseases at Research Institute of Pomology and Floriculture at Skierniewice Broniarek-Niemiec, A., S. Pluta & A.Bielenin ..................................................................... 111 Resistance of strawberry cultivars to fungal diseases Laugale, V. & I. Moročko .................................................................................................... 117 Preliminary studies on resistance of some strawberry cultivars to spider mite Tetranychus urticae Petrova, V., Z. Čudare, I. Šteinite & V. Laugale .................................................................. 119 Progress in selection of blackcurrant cultivars suitable for integrated mite management Gajek, D., S. Pluta & E. Żurawicz ....................................................................................... 123 Side effect of fungicides used in Botrytis control on occurrence of leather rot of strawberry Bielenin, A. & B. Meszka ...................................................................................................... 127 Occurence and identification of strawberry green petal phytoplasma Cieślińska, M. & B. Zawadzka ............................................................................................. 131 Efficacy of Euparen 50 WP and Euparen M 50 WG in the control of grey mould (Botrytis cinerea) and reduction of the population of two-spotted spider mite (Tetranychus urticae Koch) on strawberries Meszka, B., B.H. Łabanowska & A. Bielenin ....................................................................... 133 Usefulness of Mospilan 20 SP in Integrated Pest Management of soft fruits Łabanowska, B.H., D. Gajek & E. Niemczyk ....................................................................... 137 Preliminary IPM program for blackcurrant crop for Poland Niemczyk, E., B. Łabanowska & D. Gajek ........................................................................... 141 Storage of soft fruits Ollig, W., H. Schirmer & E. Joerg ....................................................................................... 145 Pesticide residues in soft fruits: strawberries, currants and raspberries (Monitoring 1997-98) Nowacka, A. .......................................................................................................................... 151 Consumer’s acceptance of soft fruits from Integrated Production Zmarlicki, K. ......................................................................................................................... 155 Guidelines for the Integrated Production of soft fruits – IOBC - Technical Guideline III Joerg, E. & J.Cross ............................................................................................................... 159 Work on Integrated Soft Fruit Production in Europe – Summarisation of the Workshop Joerg, E. ................................................................................................................................ 167

Integrated Production of Soft Fruits IOBC/wprs Bulletin Vol. 23 (11) 2000

pp. 1 - 6

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Prospects of developing integrated methods of small fruit production in Poland R.W. Olszak, B.H. Łabanowska, A. Bielenin, D. Gajek Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Poland It is impossible to grow farm produce with a reasonably high quality without applying pesticides. On the other hand, after some decades of employing intensive chemical control one became acquainted with serious threats resulting from that. Acquaintance of these threats, being initially only a prerogative of specialists, came – as the time went by – to broader circles of food producers and consumers. Search has been initiated recently for more harmless methods, in which the use of chemi-cals as means for intensifying the agricultural production is just one of many approaches. A novel system of production was elaborated in cooperation of science and practice and called IP (Integrated Production). It is not just a simple integration of different plant protection methods. It is virtually a broadly understood integration of hitherto existing knowledge about the ecology of agrocenoses, biology of different plant species, their pests and pathogens and natural enemies of the pests, about the soil and agrotechnics and weather. Activities undertaken within the framework of Integrated Production systems are aimed at reducing the necessity of applying chemical means of production (mainly fertilisers and pesticides) and consequently at lowering the probability of detecting their residues in fruits – even within the limits permitted. One should be aware of the fact that fruits constitute that particular group of food whose considerable quantity is consumed fresh, without processing. Basing on earlier elaboration (IOBC/WPRS Bulletin 16, 1993), new "Directives for Integrated Production of Small Fruits in Europe" have been worked out in 1997. The Polish edition of these directives will be issued soon but some information was published already. Particularly much attention is paid to elaborating the methods of integrated control of pest and pathogens, which is worked out by the staff of Plant Protection Department of the Research Institute of Pomology and Floriculture. In the present work we bring forward those elements which may be utilised at up-to-day stage of our knowledge. For presenting the problems more lucidly we put them separately for particular groups of agrophagous organisms. Integrated control of pests of small fruits (currants, raspberries and gooseberries) In the case of pests the proper monitoring and evaluation of the threats are of an extreme importance. The situation that a treatment is applied just because it is indicated in the control program for given plant species can not be approved. The second substantial factor determining the occurrence of some pests or at least decreasing their negative impact on the plantation is the quality of the nursery material to be planted. The presence of other plantations in the neighbourhood and first of all their phytosanitary stage is also of utmost importance. For making proper decisions it is necessary to know the biology of important groups of pests as well as rational means of their control. Plantivorous mites represented by two groups of a great economical importance – eriophyid mites (Eriophyidae) and spider mites (Tetranychidae) – belong undoubtedly to important pests. Among eriophyid mites the species

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most noxious and also difficult to control is blackcurrant gall mite (Cecidophyopsis ribis) (Gajek at al., 1996 and 1999). An ideal method to deal with this pest would be an introduction of resistant varieties into plantations. Unfortunately, up to the present we have not succeeded in breeding a variety with a high resistance to the pest and of high utility values and suitable for mechanical harvesting. Thus, for founding new plantations it is recommended to use only nursery material of a highest quality and – as far as possible – to localise them at places isolated from other plantings. Regular surveys of the plantation at the leafless stage and removing buds infected with the gall mite is necessary, too. Better prospects of integrated control exist in the case of such important pests as spider mites, the main representative of which on berry shrub is two-spotted spider mite (Tetranychus urticae). Results of numerous experiments prove that populations of this pest, especially on blackcurrants, can be effectively limited by predatory mites from the family Phytoseiidae (Kropczyńska & Czajkowska, 1995; Niemczyk at al., 1997). The use of pesticides selective (or at least partially selective) in relation to phytoseiid mites is required in the production process. Such acaricides are e.g. Nissorun 050 EC, Nissorun 10 EC (hexitiazox) and Omite 30 WP (propargite) (Łabanowska and Maciesiak, 1996). Another pest imposing a heavy impact on currant production in some regions is the currant shoot borer (Lampronia capitella Clerk., syn. Incurvaria capitella Cl.). Caterpillars of that species begin to feed in buds during the period of their splitting. Within its development time the caterpillar damages several subsequent buds. In the last years an increased of occurrence of this pest is observed, thus its control on many plantations is necessary. The most appropriate term for executing control treatments against currant shoot borer is the period when its caterpillars are leaving winter hiding places and penetrate into buds (March and sometimes even February). Monitoring the occurrence of the pest can be executed by means of glue bands placed at the lower parts of currant shoots before bud split. In that period application of preparations partially selective, like phosphoorganics and even pyrethroids is admitted because most of the beneficial insects and mites still remain in winter hiding places. Many aphid species (Aphididae) – vectors of viral diseases, particularly menacing to raspberry cultivation – occur on berry shrubs. In natural conditions numerous enemies keep aphid populations restricted within some limits. Unfortunately, beneficial insects occur frequently too late, after considerable damages are already caused by the pests. For chemical control of pests belonging to that group selective products like Pirimicarb or Triazamate are recommended above all. Sometimes pests whose larvae devour leaves occur on berry plants. A great number of those pest can strip the plants bare of leaves. The most important species damaging leaves of currants and gooseberry are currant worm (Pteronidea ribesii Scop.) and small gooseberry sawfly (Pristiphora pallipes Lep.). In case when pests population reaches economic threshold level, they may be controlled with biopreparations based on Bacillus thuringiensis (Thiuridan, Bacilan and Bactospeine 16 000 WP). An important group of currant and raspberry pests are also midges (Cecidomyiidae). Quite numerous and causing severe losses on currants is black currant midge (Resseliella ribis Marik.) and on raspberry – the raspberry cane midge (Resseliella theobaldi Bar.). The larvae of these small dipteran insects feed under the skin of youngest shoots and cause their decay. Considering the feeding peculiarity of this pest, controlling its larvae not always gives satisfactory results. Thus, it is purposeful to control adult insects prior to their egg-laying. Optimum treatment timing can be determined by means of monitoring the occurrence of the pest. For both species of cecidomyiids mentioned above the suitable method is to signal the term of egg-laying. This method is based on making artificial wounds on shoots and observation of egg laying females (Łabanowska, 1997). Monitoring the process of egg-laying

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on blackcurrants has to be initiated soon after blossoming and conducted at least to fruit harvest. On raspberry, observations shall begin before blossoming and continue to the end of August. The control is executed in the period of intensive flight and egg-laying by females of the 1st and 2nd generation. The 1st generation on currants is controlled during the period between blossoming and harvesting fruit and the 2nd one immediately after harvest. On raspberry the pest is controlled usually just before blossoming and after harvest. Pesticides like phosalone (Zolone 35 EC) and fenitrothion (Owadofos 540 EC and Sumithion 500 EC) can be used in integrated fruit production,. Clearwing moths (Sesiidae) exert an essential impact on small fruit bushes in some regions. Their best known representative is currant clearwing moth (Synanthedon tipuliformis Cl.), whose caterpillars damage mainly currant shoots but can also destroy shoots of gooseberry. A related species – raspberry clearwing moth (Pennisetia hylaeiformis Lasp.) is known from raspberry. Its caterpillars destroy the lower part of shoots and the root neck of raspberry, what leads to drying up and breaking down shoots. This species occurs locally on raspberry in Poland and only there requires to be controlled. Controlling clearwing moths is conducted in the period of moths flights and the optimum term is determined on the base of the catches of moths into pheromone traps (Łabanowska & Gajek, 1999). Traps for catching currant clearwing moth are available at the present in Poland. They are hung on currant bushes after blossoming and the number of moths caught is observed. Strawberry blossom weevil (Anthonomus rubi Herbst) and raspberry beetle (Byturus tomentosus Fabr.) are ranked as crucial pests on raspberry plantations. These beetles require systematic control. The first of them destroys flower buds of raspberry while the second causes vermination of fruits. The occurrence of the beetles on plantations can be monitored by means of white glue traps hung on bushes 2-3 weeks before raspberry blossoming and systematically inspected for the number of insects caught. Unfortunately, the choice of substances both selective and efficient in controlling beetles is scarce. Before blossoming phosalone or fenitrothion can be used, while during blossoming – one of the pyrethroids in case of a need. Integrated control of pathogens on small fruit bushes At the present stage of production controlling diseases on small fruit bushes – similarly as controlling pests – requires many chemical treatments. Limiting the application of chemical methods or improving their efficacy can be attained by applying a complex program, which combines methods aiding and completing the chemical control. The healthiness of the planting material is one of the factors very important in integrated control of diseases. This is particularly important for preventing losses caused by viral and mycoplasmatic diseases. Pathogens of these diseases are introduced into the newly-founded plantation together with the infected plant material, being then spread within the plantation by pests, mainly gall mites, e.g. blackcurrant reversion by blackcurrant gall mite, and gooseberry vein banding by aphids. Thus, the choice of the stand for new plantations is very important. The best situation is when they are not founded in the vicinity of already existing plantations. An essential element of integrated control allowing to reduce and in some cases even to eliminate chemical treatments is a skilful utilising of the natural resistance of varieties. Different control programs should be applied on blackcurrant variety Ben Lomond susceptible to mildew and on variety Triton especially susceptible to currant rust.

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Besides susceptibility of varieties also the intensity of diseases on individual plantations is taken into account in programs of integrated pathogen control. To this end, conducting frequent inspections is indispensable. Accurate surveys connected with removal of infected shrubs are particularly important in limiting damages caused by such grave diseases as black currant reversion or gooseberry vein banding. The most dangerous diseases of currants in Poland are anthracnose and leaf spot and, in the case of blackcurrants, also American gooseberry mildew and currant rust. The fungicides recommended belong to different chemical groups and, if possible, their activity is utilised against several pathogens occurring simultaneously at the plantation. In choosing fungicides, attention is paid to the necessity of their rotation in order to prevent building up pathogen’s resistance. Broad spectrum fungicides belong to the IBE group; they allow to control at the same time all fungal diseases of currants. However, taking into consideration the possibility to generate pathogen’s resistance, preparations like pirazofos (Afugan 30 EC), bupirimate (Nimrod 25 EC), dinocap (Karathane 18.25 WP) and triforin (Saprol) should be incorporated into the control program of American gooseberry mildew, while other fungicides, first of all those containing mancozeb, ditanon (Delan 750 SC) and triforin (Saprol 190 EC) – in the control programs of remaining diseases. Besides anthracnose, the heaviest losses on gooseberry plantations are caused by American gooseberry mildew. The more so that the variety White Triumph, fundamental for gooseberry production in Poland, is characterised by a high susceptibility to that disease. Recommendation for controlling American gooseberry mildew are the same as in the case of blackcurrants, though the term of starting treatments is earlier, just after blossoming of gooseberry (Goszczyński & Partyka, 1995). Basic diseases occurring on raspberry plantations are grey mould and raspberry spur blight. The efficacy of chemical control of these diseases depends in a great extent – apart from natural resistance of the variety of course – on accuracy of executing the treatments. The system of conducting the plantation is here of the utmost importance. High efficacy of chemical sprayings is impossible on overcrowded plantations. A treatment improving the efficacy of raspberry spur blight control consists of cutting off the youngest, growing shoots (Cimanowski et al., 1992/93). Fungicides recommended for controlling the diseases in question are well known and their stock did not change for several years. Considering the possibility of occurring resistant forms of the fungus causing grey mould, preparations from the group of dicarboximides (Sumilex 500 SC, Rovral 50 WP and Flo 255 SC) should be applied not more frequently than twice a season. A product meriting attention is dichlofluanid (Euparen 50 WP) for its propensity of limiting the occurrence of spider mites, when applied twice to control grey mould. Control of the last disease creates many problems in repeating varieties. Simultaneous blossoming and harvest of fruits renders impossible conducting chemical control by means of fungicides registered at present. One ought expect an improvement of the situation soon. A novel fungicide fenhexamid (Teldor) has been introduced into the register. Its very short preharvest time will allow executing treatments between subsequent harvests. In the near future one shall expect a further, fast development in breeding new, resistant varieties and at the same time a development of pesticides more and more efficient and safe, and thereby more useful for the integrated production.

5

References Cimanowski J., A. Bielenin, J. Dadej, H. Osuch, H. Rechnio. 1992/93. Wpływ wycinania

pierwszych, młodych pędów i ochrony chemicznej na zdrowotność, wzrost i owocowanie maliny. Pr. Inst. Sad. Ser. A, 31: 123-128.

Gajek, D., J. Boczek, J. Nowacki. 1996. Black currant cultivars resistant to the gall mite (Cecidophyopsis ribis Westw.) as an element of integrated pest management. International Conference on Integrated Fruit Production', Cedzyna, Poland, August 28 – September 2, 1995, Proceedings of the Meeting. IOBC/wprs Bulletin 19(4): 349-350.

Gajek, D., S. Pluta, E. Zurawicz. 1999. Wstępne wyniki badań nad hodowlą odmian porzeczki czarnej odpornych na wielkopąkowca (Cecidophyopsis ribis /Westw./). Materialy VIII Ogólnopolskiego Zjazdu Naukowego Hodowców Roślin Ogrodniczych, "Hodowla Roślin Ogrodniczych u progu XXI wieku, Lublin 1999, T.II, pp. 475-479.

Goszczyński, W., Z. Partyka. 1995. Ochrona agrestu przed amerykańskim mączniakiem. Ogólnopolska Konferencja Ochrony Roślin Sadowniczych, 1-2 luty 1995, ISK Skierniewice, pp. 173-174.

Kropczyńska, D., Czajkowska B. 1995. Skuteczność drapieżnych roztoczy (Phytoseiidae) w ograniczaniu liczebności przędziorka chmielowca na porzeczce czarnej. Materiały Ogólnopolskiej Konferencji Ochrony Roślin Sadowniczych, Skierniewice, 1-2 luty 1995, pp. 117-119.

Niemczyk, E., Z. Nowakowski, I. Kumor. 1997. Występowanie i efektywność drapieżnych roztoczy (Phytoseiidae) w zwalczaniu przędziorka chmielowca na czarnych porzeczkach. Ogólnopolska Konferencja Ochrony Roślin Sadowniczych. Skierniewice, 1997, pp. 12-125.

Łabanowska, B.H., 1997. Dynamika składania jaj i efektywność zwalczania pryszczarka porzeczkowca pędowego – Resseliella ribis (Marik.) (Diptera, Cecidomyiidae). Zesz. Nauk. Inst. Sadow. Kwiac. 4: 135-147.

Łabanowska, B.H., D. Gajek , 1999. Monitoring i zwalczanie najważniejszych szkodników porzeczki czarnej. Progress in Plant Protection / Postępy w Ochronie Roślin, 39 (1): 305-311.

Łabanowska, B.H., A. Maciesiak, 1996. Effectiveness of new generation acaricides and mixtures of two acaricides in control of the spider mite (Tetranychidae) on apple, blackcurrant and strawberry. Proc. Symp. on „Advances of Acarology in Poland” Siedlce, September 26-27, 1995, pp. 123-126.

6


pp. 7 - 10

7

The standard and the integrated strawberry production in Poland Barbara H. Łabanowska, Anna Bielenin Research Institute of Pomology and Floriculture, Skierniewice, Poland Abstract: The total area covered by strawberry plantations in Poland is over 55 000 ha. Nearly 70-75% of the strawberry production is destined for processing, mainly for freezing. The dominant cultivar for the industry is Senga Sengana while for the fresh fruit market mainly Elsanta, Kent, Marmolada, Selva, Tarda Vicoda and Polish cultivars Dukat, Elkat and Kama are grown. In the recent years the modern technology of strawberry production has been introduced. A few groups of farmers start to grow strawberries under IFP (Integrated Fruit Production) rules. They got their first IFP certificates three years ago and the next group of farmers shall get them soon. The problems with plant protection in IFP are described. Key words: integrated production, strawberry, acaricides, soil pest control, Tetranychus urticae, Phytonemus pallidus, Anthonomus rubi, Botrytis cinerea, Mycosphaerella fragariae, Sphaerotheca macularis. Introduction For many years Poland has been one of the leaders in strawberry production. In 1999 the total area covered by strawberry plantations was over 55.000 ha, which is about sixteen percent less than it was eight years before. The annual production of strawberries in Poland is 150.000 – 200.000 tons. The fruit yield depends on growing area, but the weather conditions, particularly during the blossom and harvest time have also a considerable influence. For example in 1998 and 1999 very intensive rainfall during the harvest of strawberries caused a severe grey mould occurrence which destroyed a big part of the crop. On the other hand, the price variations from year to year badly influence the future development of strawberry production. Nearly 70-75% of the strawberry production is destined for processing, mainly for freezing. Polish strawberry production has been dominated by one variety – Senga Sengana, fruit of which have excellent features for processing. This cultivar covers about 75% of commercial strawberry plantations. In recent years the consumption of fresh strawberries increased considerably. The foreign cultivars such as Elsanta, Kent, Marmolada, Selva and Tarda Vicoda have been. However, they are not well adapted to Polish climatic and soil conditions. Some of these cultivars, especially Elsanta, are very sensitive to root diseases and freezing injuries during winter time. Therefore in our strawberry breeding programme we are looking for the cultivars, which better suit the local climatic conditions. The new cultivars developed in Poland and already grown by Polish farmers (Dukat, Elkat and Kama) are probably less attractive when compared with Elsanta cv., but they are resistant, or at least less sensitive to root diseases and frost. Two of them: Dukat and Elkat cvs are also resistant to leaf diseases. The largest strawberry growing areas are located in Central, South-eastern and South-western parts of Poland. However, the strawberries are also grown in other regions of the country. Most of the plantations are small, about 0,1-0,25 ha, and they belong to small agricultural farms. By growing strawberries the farmers get an additional income. On the

8

other hand, the growers who have small plantations are not specialised in strawberry production. They are not always planting healthy, certified planting material and they can not maintain proper crop protection. The strawberry plantations are usually exploited for 3 or even 4 years. The small area of plantations and the lack of professional skills of growers are the main reasons of low yielding. However, in recent years the modern technology of strawberry production replaces the traditional one. A number of large strawberry farms (from several to over 100 ha) increased during the last few years. Young, well-educated growers who apply the newest and most sophisticated production technologies usually manage such farms. They take advantage of much higher price they are offered for the high quality fruit for fresh market compared with the price of fruit for processing or freezing. The high quality dessert fruit are produced mainly in the vicinities of large towns, where the growers have a better possibility to sell them. Some of the growers decided already a few years ago to increase the fruit quality by implementing the IFP rules. They use only certified planting material and modern spraying techniques to protect strawberries against pests and diseases. These growers have been organised in IFP groups of farmers. The first IFP group started only six years ago and the growers got their first IFP certificates three years ago. In 1999 the certificates were issued to 65 strawberry growers, organised in six groups located mainly in the Central and Southern parts of Poland. The area of strawberries grown under IFP rules during last years reached 215 ha, and the production of fruit was about 2.250 tons. The next few groups of farmers has just started integrated strawberry production in their farms, and they will get certificates in the near future. The growers who are interested in IFP have to learn how to do it. They are organised in groups, consisting of several members and a leader, usually being their instructor. They participate in 2-3 day IFP courses, which are organised by the Research Institute of Pomology and Floriculture in Skierniewice. They are taught the principles of IFP rules described in a brochure published by the Institute (Żurawicz et al. 1995). The brochure contains instructions on soil quality, plant protection methods and simple techniques to estimate the threshold levels for main pests and diseases. The growers get the certificate after attending the course and having produced strawberries according to IFP rules for two years. The Polish strawberry growers have problems with some pests and diseases in their production. We are looking for the methods, which can help them to solve their problems in plant protection. In some plantations the farmers have problems with the soil pests such as larvae of white grubs (Melolontha melolontha), wireworms – larvae of Elateridae and larvae of strawberry root weevils (Otiorhynchus sp.). So far we have no method to control these pests and therefore the strawberries should be planted in the fields which are free of them. If there is no chance to find such a field, the soil pest control is needed prior strawberry planting. A granular formulation of diazinon should be applied during the period from the late spring up to the end of summer. A similar problem with soil diseases such as Verticillium or Phytophtora occurs in some regions of Poland where the foreign dessert cultivars are grown. Since there is no efficient method to control these diseases, the soil has to be free of them if the grower wants to plant the sensitive cultivars. The planting material has to be certified and free of pests, mainly nematodes, strawberry mite (Phytonemus pallidus spp fragariae Zimm.), two-spotted spider mite (Tetranychus urticae Koch.) as well as viral and fungal diseases. So far we have no methods to control the nematodes and viruses in the field.

9

The strawberry mite is only a problem when it is brought with a planting material. For a long time endosulfan (Thiodan 350 EC) has been used to control the mite. In the integrated strawberry production, the use of endosulfan is permitted once a year. Therefore we keep looking for an alternative acaricides, which could be useful to control the strawberry mite. Among the acaricides tested the promising results were obtained with amitraz (Mitac 200 EC), fenazaquin (Magus 200 SC), pyridaben (Sanmite 20 WP), fenpyroximate (Ortus 05 SC), propargite (Omite 30 WP), abamectin ( Vertimec 018 EC) and some others (Łabanowska 1992,1995a). The most suitable for IFP program is propargite, which reduces the strawberry mite population quite well, and is also recommended for a control of two-spotted spider mite. The farmers who use healthy plants without mites don't have problems with these pests during two – three years of the strawberry growing. Two-spotted spider mite is a problem in many plantations, especially during hot and dry weather during blossom and harvest time. Among the tested acaricides good results in control of two-spotted spider mite were obtained with hexythiazox (Nissorun 050 EC, Nissorun 10 EC), propargite (Omite 30 WP), fenazaquin (Magus 200 SC), mixture propargite + hexythiazox (Omite 30 WP + Nissorun 050 EC), mixture amitraz + clofentezin (Mitac 200 EC + Apollo oil), fenpyroximate (Ortus 05 SC) and pyridaben (Sanmite 20 WP) (Łabanowska 1995 b,c) In the plantations with IFP program hexythiazox and propargite are the most useful. The economic threshold level for two-spotted spider mite is 1-2 mites in active stage per 1 leaflet before blossom, 2-3 mites per leaf after full blossom and 5-6 mites per leaf after fruit harvest. The strawberry blossom weevil is the second most important pest, which must be controlled each year on the majority of the commercial strawberry plantations. Many insecticides are effective in control of this pest (Łabanowska and Gajek 1992, Łabanowska 1997), but for the IFP program phosalone (Zolone 35 EC) is the main product. During the last two years we obtained good results with acetamiprid (Mospilan 20 SP) but the chemical has not been registered yet for strawberries (Łabanowska et al., 2000) Fungal diseases have to be controlled in the strawberry plantations every year. Grey mould (Botrytis cinerea) is very efficiently controlled with one of the most important fungicides dichlofluanid (Euparen 50 WP). When used 2 – 4 times during the blossom time it controls: grey mould and strawberry leaf spot (Mycosphaerella fragariae) and also reduces the population of two-spotted spider mite (Meszka et al., 2000). Dichlofluanid used against grey mould also reduces powdery mildew (Sphaerotheca macularis). Additional treatments with the specific fungicides are needed only on the very susceptible cultivars such as Elsanta. Other fungicides very useful in control grey mould are: procymidon (Sumilex 500 SC), iprodion (Rovral 50 WP, Rovral FLO 255 SC) (belong to dicarboxyimide group), and pyrimetanil (Mythos 300 SC). The useful fungicide in control of grey mould and strawberry leaf spot is tiuram (Thiram Granuflo 80 WP and Pomarsol Forte 80 WG). Depending on the weather conditions and cultivar susceptibility, 3-5 chemical treatments must be done every year. The modern technologies of production with IFP rules require from growers some knowledge about the biology of pests and fungal diseases on strawberries as well as about the insecticides and fungicides used to control them. A systematic inspection of plantations for monitoring pests and diseases are necessary to keep the plants in good condition and to get a good yield of fruit.

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Acknowledgements Grateful thanks are due to Mr. J. Mochecki, Mrs. B. Zaradna and prof. E. Żurawicz for their help. References Łabanowska B. H., 1992: Effectiveness of acaricides in control of strawberry mite

(Phytonemus pallidus spp. fragariae Zimm.) Fruit Sc. Rep. 19: 137-146. Łabanowska B.H., 1995 a: Acaricides for control of the strawberry mite – (Phytonemus

pallidus ssp. fragariae Zimm.) The Acari, Dabor, Warszawa, 633-637. Proc. 2nd Symposium of EURAC, 1992.

Łabanowska B. H., 1995 b: Przydatność mieszanin amitraz + klofentezyna oraz propargit + heksythiazoks i innych akarycydów do zwalczania przędziorka chmielowca – Tetranychus urticae Koch na truskawce. Zesz. Nauk. Inst. Sadow. Kwiac. 2: 65-75.

Łabanowska B.H. 1995 c: Effectiveness of new generation acaricides in the control of two-spotted spider mite (Tetranytchus urticae) on strawberry. IOBC/wprs Bulletin 19(4): 415-416.

Łabanowska B.H. 1997: Control of the strawberry blossom weevil (Anthonomus rubi Hbst.) on strawberry. J. Fruit Ornam. Plant Res. 5: 157-162.

Łabanowska B.H., Gajek D. 1992: Control of strawberry blossom weevil (Anthonomus rubi Hbst.) with new insecticides. Fruit Sc. Rep. 19: 167-172.

Łabanowska B.H., Gajek D., Niemczyk E. 2000: Usefulness of Mospilan 20SP in integrated pest management of soft fruits. IOBC/wprs Bulletin 23(7): 137-139.

Meszka B., Łabanowska B.H., Bielenin A. 2000: Efficacy of Euparen 50 WP and Euparen M 50 WG in the control of grey mould Botrytis cinerea and reduction of the population of two-spotted spider mite (Tetranychus urticae Koch) in strawberries. IOBC/wprs Bulletin 23(7): 133-136.

Niemczyk E. et al., 1993: Integrowana produkcja owoców (Praca zbiorowa). Instr. 173, wyd. IV. ISK, Skierniewice, pp. 55.

Niemczyk E. et al., 1997: Integrowana produkcja owoców (Praca zbiorowa). Instr. 224, wyd.VI. ISK, Skierniewice, pp. 67.

Program Ochrony Roślin Sadowniczych na rok 1999. Instytut Sadownictwa i Kwiaciarstwa, Skierniewice and Agrosan, S.C. 1999, pp.120.

Rynek owoców i warzyw stan i perspektywy, 1999, Nr. 14, Wyd. MriGŻ, Inst. Ekon. Rol. i Gospodarki Żywnościowej, Raporty Rynkowe, Lipiec 1999.

Zurawicz E., Bielenin A., Doruchowski G., Lisek J., Łabanowska B. H., Płocharski W., 1995:Integrowana produkcja owoców truskawki. Instr. 201, wyd. ISK, Skierniewice, pp. 59.

Żurawicz E., Łabanowska B. H., Bielenin A., 1997: Integrated strawberry production in Poland. Proc. Third Int. Strawberry Symp. Acta Hort. 439: 957-961.


pp. 11 -16

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Strawberry production in Latvia Valda Laugale Pūre State Horticultural Research Station, Tukuma raj., LV-3124, Latvia Abstract: Strawberries are cultivated recently on more than 500 ha in Latvia. The income from production of strawberry is higher than from other agricultural crops and therefore the cultivated area is increasing rapidly Most of the strawberry growers have small fields, less than 1 ha in size. The level of mechanisation and plant protection is very low at many farms. The yield of strawberries is also very low – on average 6 tons/ha. Berries are sold fresh on local markets. The processing industry is still developing. Strawberries are mainly grown on flat fields in rows with density of 30 – 40 thousands plants/ha. Farmers use straw and sawdust for soil mulching, but some of them use grass as a living mulch. In the last years farmers are becoming interested in the use of different synthetic covering materials such as polypropylene and polyethylene. The most widespread and productive cultivars in Latvia are Zefyr and Induka. The following cultivars are included in the List of Recommended Cultivars for Commercial Plantings in Latvia (year 1999): Zefyr, Venta, Festvalnaya, Induka, Corona, Dukat, Tenira and Senga Sengana. Most of the farmers are growing strawberries with minimal pesticide application. It is due to the shortage of financial resources. There is also a limited number of pesticides registered for strawberries in Latvia. Key words: strawberry, area, growing systems, cultivars, plant protection, propagation Introduction The first information on garden strawberry growing in Latvia dates back to 1878 (Bite et al., 1997). The main cultivation region was Jurmala (near the capital city Riga). Before the Second World War strawberry acreage in Latvia was about 1000 ha. The area was reduced in subsequent years: in 1970 only 300 ha were cowered with strawberries and 78 % of this acreage was in small gardens. Only 0.5 kg of strawberries was produced per inhabitant. An agricultural survey in 1985 indicated that strawberry plantings totalled 397 ha, with only 15 % in public property, and 85 % in private property. In 1996 there were about 500 ha of strawberries and today it is increasing rapidly. Experience shows that strawberry production gives higher income in comparison with other agricultural crops. Moreover, in the last years our government has started to subsidise establishment of perennial horticultural plantings, including strawberries. Only in 1998 the acreage of strawberry plantations increased by 79.3 ha (16 %) due to subsidies. Most of the farms have area under strawberry production smaller than 1 ha, but largest farms have more than 10 ha. The level of mechanisation and plant protection is very low on many farms and this is the main reason for very low yields – an average of 6 tons/ha. Yields at the best farms are about 20 tons/ha. Strawberries are planted mainly in regions close to larger towns. Berries are sold fresh on local markets. Due to increasing area of strawberry cultivation and fairly short harvesting season, it becomes difficult to sell the production and prices fall down. The processing industry is still developing.

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Weather conditions

Latvia is located in the maritime climate zone. Climate is influenced by Baltic sea and warm Gulf Stream. Though territory of the republic is not large, weather at different locations is quite variable. The warmest month in Latvia is July and the coldest are January and February. The highest average temperature of many years in July is +17,8 oC. In the winter the average temperature of many years in the Western part of Latvia is -2.5oC, but in the Eastern Latvia – 6,9 oC. The lowest temperature on the snow surface – -48 oC – was recorded in the winter of 1978/79. Climate in Latvia is characterised by humid and cold winters with a permanent snow covering, though quite often there are thaws and glazed frosts, which have negative influence to strawberry overwintering. Only during 2 months – July and August, temperature never drops below 0oC. Especially dangerous for strawberries are late spring frosts. Strawberry blossoming in open field starts usually at the end of May and harvesting starts at the end of June and lasts for about a month. Table 1. Results of testing of some strawberry cultivars at Pûre State Horticultural Research

Station (1997-1998, average of 2 years)

Cultivar % of total yield Fruit

Winter hardiness

*

Total yield (t/ha)

1st quality

Botrytis damaged

Weight (g)

Attrac-tiveness*

Flavour *

Darunok Vchiteliu 2.6 0.6 33 2.3 9.2 3.4 4.3

Desnyanka 3.8 5.9 51 2.4 11.2 3.7 4.2 Festivalnaya Romascha 3.3 3.2 63 2.3 11.1 4.2 4.1

Roxana 3.2 2.5 52 1.9 10.3 4.0 3.6 Induka 4.3 12.5 69 2.5 13.5 4.3 4.2 Korona 3.5 5.3 69 1.3 13.6 4.5 4.5 Taganka 3.9 8.6 53 2.4 11.0 3.9 4.0 Zefyr 4.3 7.1 66 2.7 13.3 4.1 4.2 Siurprise Olimpiadi 3.9 8.2 66 3.3 13.3 4.5 4.0

Holiday 3.7 5.4 71 1.6 12.9 4.1 4.2 Senga Sengana 3.8 6.8 44 2.7 11.0 4.2 4.1

Elsanta 2.2 2.5 74 0.9 13.9 4.5 4.3 Kokinskaya Pozdnaya 3.2 5.9 77 4.1 15.4 4.3 3.9

Bogota 2.3 3.0 69 0.8 13.4 4.4 4.4 * – ratings range 1-5 with ``5`` being the best Growing systems Strawberries are mainly grown on flat fields with spacing of 0.25 – 0.30 x 0.70 – 1.00 m (30 000 – 40 000 plants/ha), depending on equipment. Fields are usually kept for 3-4 years. Most of farmers are using plant rotation system.

13

There are 2 main strawberry planting times in the open field in Latvia – May and August. To establish plantings growers use freshly dug plants. Some experiments had been done on use of cold-stored plants, which can significantly prolong strawberry production season (Laugale, 1998). Due to difficulties to get cold-stored planting material, the method is still not ver popular among farmers. Irrigation is one of main conditions for getting high yields. Farmers use mainly various overhead irrigation systems, but interest is risen also in drip irrigation. During the last years there is an increased interest in using different synthetic covering materials as polypropylene and polyethylene, but it demands higher investments. Because of that, only some farmers nowadays are growing strawberries on beds with black plastic mulch on larger area. Farmers use for soil mulching mainly straw and sawdust, but some of them also use grass as a living mulch. Polyethylene sheets and fibre tissue are used for strawberry forcing. This prolongs harvest season by 2 weeks and protects the flowers from spring frosts. Growing strawberry in greenhouses and plastic tunnels is not popular due to a very high economic input. Cultivars In the List of Recommended Cultivars for Growing in Latvian Conditions in Commercial Plantings (year 1999) following cultivars are included: Zefyr (Danish origin) Venta (Lithuanian), Festvalnaya (Russian), Induka (Dutch), Korona (Dutch), Dukat (Polish), Tenira (Dutch) and `Senga Sengana` (German). `Zefyr` and Ìnduka` are most widespread and productive ones. The testing of the newly introduced strawberry cultivars have been done in the Pure State Horticultural Research Station. The highest yield in the trials was obtained from Ìnduka`, while more 1st grade and larger berries gave cultivars `Kokinskaya Pozdnaya` and Èlsanta` (Tab. 1). In the evaluation of attractiveness the highest grade received `Korona`, `Siurprise Olimpidi` and Èlsanta`. `Korona` was also characterised by a very good flavour. Interesting was also cultivar Darunok Vchiteliu because of a very early ripening, but its yielding and winter hardiness were low. Cultivars Kokinskaya Pozdnaya and Bogota are characterised by a very late ripening. Unfortunately, `Bogota` had very low winter hardiness in our conditions. The same applies to Èlasanta`, which is very popular in many European countries. Plant protection The major pests on strawberries in Latvia are strawberry mite (Tarsonemus pallidus), two-spotted spider mite (Tetranychus urticae), strawberry blossom weevil (Anthonomus rubi), leaf beetle (Galerucella tenella) and Lygus bugs. The major diseases are grey mold (Botrytis cinerea), leaf spot diseases (caused by Ramularia tulasnei, Marssonina potentillae f. fragariae), verticillium wilt (Verticillium albo-atrum) and powdery mildew (Sphaerotheca macularis f. fragariae). In the last years there was an increased risk of spreading other dangerous strawberry diseases in Latvia due to the import of the planting material from abroad. Most of the farmers are growing strawberries with the minimal pesticide application. It is mostly due to the shortage of financial resources. There is also a limited number of plant protection products registered for use on strawberries in Latvia (Tab. 2) and during the vegetation period the use of pesticides is allowed to a limited extent. We have not yet worked out the IFP program and the certification system for soft fruits in Latvia but since the interest in this method of fruit production is increasing, it will be one of targets.

14

Table 2. The list of plant protection products registered for strawberries in Latvia (1995-2005).

Plant protection product Harmful organism Max applications

per season

Fungicides: Baileton 25 WP (triadimefon 250 g/kg, Bayer)

Mildew 2

Euparen – M 50 WG (tolyfluarid 500 G/KG, Bayer, will be registered in 2000)

Grey mold, leaf spots, mildew

2

Fundazol 50 WP (benomyl 500 g/kg, Hinoin)

Mildew, grey mold, leaf spots

2

Ronilan OF (vinclozolin 50 %, BASF) Grey mold 2 Thiovit 80 DG (sulphur 800 g/kg) Mildew, spider mite 3 Insecticides: Decis 2,5 EC (deltamethrin 25 g/l, AgrEvo)

Blossom weevil 1

Fastac EC (alpha-cypermethrin 100 g/l, Cyanamid)

Blossom weevil, aphids, bugs

2

Mitak 20 EC (amitraz 200 g/l, AgrEvo) Spider mite 1 Herbicides: Agyl 100 EC (propaquizafop 100 g/l, Ciba-Geigy)

Monocotyledonous weeds

2

Focus Ultra EC (cycloxidim 100 g/l, BASF)


2

Fusilad Super (butil-P-fluazufop 125 g/l, Zeneca Agrochemicals)


2

Goltix 70 WP (metamitron 700 g/l, Bayer)

Dycotyledonous weeds, in spring

1

Lontrel 300 (klopyralyd 300 g/l, Dow Elanco)

Dycotyledonous weeds, esp. Cirsium arvense, in autumn

1

Zellec Super EC (etoxetilhaloxyfop 104 g/l, Dow Elanco)


1

Plant propagation There are not strict regulations at present for planting material quality in Latvia. In 1998 a new Ministry project on "Horticultural planting material growing and marketing" was worked out but it is not yet accepted. We have several institutions, which are dealing with the strawberry propagation by tissue culture and producing disease-free plants. Each institution is responsible for plant quality on their own. We still do not have an organised system for quality control and certification.

15

The trials on the comparison of micropropagated and traditionally propagated plants set at Pūre State Horticultural Research Station show that in vitro plants produce more runners, give higher yield with better quality berries and are more resistant to unfavourable weather conditions in comparison to traditionally propagated plants (Petrevica et al., 1996). Many farmers are propagating strawberries on their farms from runners. Propagation fields usually are not separated from production fields, what increases the risk of the infection with pests and diseases. Future The introduction of new, high yielding cultivars and the improvement of cultivation systems have increased commercial significance of the strawberry production in Latvia. The main tasks for strawberry growers today are to decrease production costs, to extend production season and to develop industrial co-operation and processing. We have to pay much attention to biological production and to work out the IFP system, as demand for such production is increasing in the entire World. References Bite A., Laugale V. and Jurevica Dz., 1997. Strawberry culture in Latvia. Acta Hortic. 439:

403-405. Laugale V., 1998. Studies on extending of strawberry production season in Latvia.

Proceedings of 1st International Meeting of Young Scientists in Horticulture. Lednice, Czech Republic, pp. 60.

Petrevica L., Heimanis P., Laugale V., 1996. The influence of the recuperation on the productivity of strawberry. Theses II. International symposium “Breeding, propagation in vitro and disease resistance of horticultural plants”. Salaspils, Latvia,.pp. 88-89.

16


pp. 17 - 20

17

Cultivars of currants for Integrated Fruit Production Józef Gwozdecki Research Institute of Pomology and Floriculture, Pomologiczna 18., 96-100 Skierniewice, Poland Abstract: Currant collection at Skierniewice consist of about 200 cultivars. The yield was graded in July and state of foliage in September. The mean results of 1985, 1986 and 1988 assesments for several cultivars with the best foliage in autumn are presented. Key words: currant, foliage in autumn Introduction Low susceptibility of plants to pests and diseases is of a fundamental importance in Integrated Fruit Production. Healthy leaves of currants in autumn indicate a low susceptibly to some pest and diseases, mainly to leaf-fall (anthracnose) (Drepanopeziza ribis), currant rust (= white pine blister rust) (Cronartium ribicola), and spider mite (Tetranychus urticae). Material and methods The currants collection at Skierniewice consist of about 200s cultivars with 3 bushes of each and it is replanted every several years. Results obtained during 1975-1981 were already published (Gwozdecki, 1983 a, b). Results presented in this paper were obtained from the collection planted in 1984 and grubbed in 1995 (black currants) and 1999 (red currants). It was consisted of 138 black currant cultivars and 69 red/white ones. The health status of the leaves was assessed in September on years when strong defoliation occurred. Those were years 1985, 1986, 1988, and for red currant additionally 1996. Plants with no leaves received grade 0, plants with healthy leaves – grade 5. In the paper only cultivars that had the presented only cultivars healthiest leaves are presented and a few other which are more popular in production. Since for Integrated Production foliage is important but the productivity, too, the yield was measured during 9 years and expressed on a p-point scale(0 – no fruit; 5 – very abundant crop). Results The results obtained for the cultivars with the best foliage in September are presented in tables 1 and 2. Of the black currant cultivars Minay Schmiryev, Bielorusskaya Sladkaja (both from Belorus') and Swedish cv. Titania had the healthiest leaves till late autumn. However, one of them is resistant to all fungal diseases. Leaves of Titania can be injured by anthracnose, while those of two others. by mildew. After taking into consideration other features of these cultivars, Titania seems to be the best one for Integrated Production. Of the newly-bred cultivars planted in the collection very promising is Ben Connan from Scotland, with very healthy leaves.

18

Table 1. Abundance of foliage in September and yield of the healthiest black currants cultivars. Means for 1985, 1986, 1988 assesments.

Cultivar Healthiness Yield

Öjebyn 3,4 2,9 Black Reward 3,5 3,4 Triton 3,6 4,2 Ben Nevis 3,7 3,0 Consort 3,9 3,7 Bielorusskaya Sladkaya 4,4 3,7 Golubka 4,4 3,1 Barkhatnaya 4,5 1,3 Bija 4,6 2,5 Doch Sibiryachki 4,7 2,9 Kalinka 4,7 2,8 Bielorusskaya Pozdnaja 4,8 1,8 Titania 4,8 3,3 Minay Schmiryev 5,0 3,8

Table 2. Abundance of foliage in September and yield of the healthiest red and white currants

cultivars. Means for 1985, 1986, 1988, 1996 assesments.

Cultivar Healthiness Yield

Jonkheer van Tets 4,0 3,0 Mulka 4,3 3,6 Erstling aus Vierlanden 4,5 3,1 Heinemans Rote Spätlese 4,5 3,5 Kimere 4,6 3,5 Red Dutch 4,7 3,2 Rondom 4,7 3,9 Karelskaya 4,8 3,6 Fertödi Hoszufürtü 4,9 3,6

Blanka 2,7 3,7 Primus 2,4 3,3 Weisse aus Jüterbog 3,7 3,4 Blanche de Verseilles 4,2 3,4 Grosse Blanche de Dessert 5,0 3,1

19

Of the red currant cultivars Fertodi Hosszufurtu, Karelskaya, Rondom and Red Dutch had the healthiest leaves. However, Fertodi Hosszufurtu has rather small berries whereas fruits of Rondom have some strange smell. Thus, Karelskaya and Red Dutch seems to be the best cultivars for Integrated Production. The newly-bred cultivars, such like Rovada, Rosetta, Tatran, and Detvan are susceptible to anthracnose. Of the white currants Grosse Blanche de Dessert, Weisse Verseiler and Weisse aus Juterbog can be recommended for Integrated Production. Blanka and Primus, new cultivars from Slovakia, have very long strigs, but their leaves are infested by anthracnose and also by powdery mildew. Conclusions Of the cultivars evaluated in collection, the following are suitable for Integrated fruit production because of a low susceptibility to leaves pathogens and good yields: Titania (black), Karelskaya, Red Dutch (red), Grosse Blanche de Dessert, Weisse Verseiler and Weisse aus Juterbog (white), References Gwozdecki J. 1983 a: Evaluation of black currant cultivars tested in 1975-1981. Fruit Sci.

Rep. 10(3): 99-105. Gwozdecki J. 1983 b: Evaluation of red and white currant cultivars tested in 1975-1981. Fruit

Sci. Rep. 10(3): 107-111.

20


pp. 21 – 24

21

Evaluation of two methods of detection of blackcurrant reversion-associated virus (BRAV) Tadeusz Malinowski, Stanisław Pluta, Anita Kuras, Edward Żurawicz Instytut Sadownictwa i Kwiaciarstwa, Pomologiczna 18, 96-100 Skierniewice; Poland e-mail: [email protected] Abstract: Two methods: silicacapture – reverse transcription – polymerase chain reaction (SC-RT-PCR) and immunocapture-RT-PCR (IC-RT-PCR) were applied for detection of blackcurrant reversion-associated virus (BRAV) in blackcurrant plants (Ribes nigrum L.). Leaves and flowers were used as a source of tested tissue. It has been shown that both method could be used for testing during the whole growing season and they might be useful for breeders of blackcurrant in their efforts to breed for resistance against the reversion disease. However, at the current stage of development of the method, negative results (lack of virus detection) occurred quite often and therefore they should be very carefully verified. Key words: black currant, Ribes nigrum L., breeding, reversion, BRAV, detection Introduction Reversion of blackcurrant is a devastating disease occurring in most if not all countries where blackcurrant production takes place (Wood, 1991; Trajkovski and Anderson, 1992; Jones et al., 1995). Two types of reversion symptom patterns have been described: „E” or „ETR” (common, European type reversion) and „R” or „RTR” (severe, Russian type reversion). Both types are characterised by a sterility of flowers leading to a partial or even complete loss of fruit production. The putative agent responsible for reversion has been isolated recently and named blackcurrant reversion-associated virus = BRAV (Lemmetty et al., 1997). The disease is transmitted not only with a vegetatively propagated infected plant material but it can also be spread in the field by an insect vector – big bud mite (Cecidophyopsis ribis West.). The last one is by itself a serious treat to blackcurrant plantations. However, the threshold level (used in IPM) for the insect being a vector of a serious virus disease may depend on the presence of the disease sources in the vicinity. Therefore a careful testing of planting material as well as checking suspected plants in the field is necessary. The most promising strategy of long-term virus control is breeding cultivars resistant to a disease and/or its vector. The suitable program has been established at the Research Institute of Pomology and Floriculture, Skierniewice, Poland in 1986 and enhanced in 1993 (Pluta and Żurawicz, 1993; Gajek et al., 1995). During the course of the work it is necessary to test for the presence of disease agent in a number of plants. The observation of symptoms occurring on flowers and leaves of tested plant or indicator has been the only method available for a long time. However, it may take up to two years for symptoms to develop after grafting (Pluta and Żurawicz, 1998). Revealing of the nucleotide sequence of BRAV RNA and preparation of polyclonal antibodies enabled the development of IC-RT-PCR method of virus detection (Lemmetty et al., 1997; Latvala et al., 1997). This method (IC-RT-PCR) has been checked in our laboratory for the suitability for breeding purposes. Since specific antibodies are required for IC-RT-PCR and those are not

22

always available we first tested silicacapture-RT-PCR method (SC-RT-PCR) in which the same primers and PCR protocols were used, but a total nucleic acids isolation has been utilised eliminating the need for specific antibodies. Material and methods Infected black currant plants cultivars ‘Ben Lomond’, ‘Titania’ and ‘Bona’ were prepared by grafting with the material showing symptoms of reversion type “E” or “R”. Healthy plants cvs. ‘Bona’ and ‘Titania’ were kept under screenhouses and treated with pesticides to avoid risk of uncontrolled infection. Leaves and flowers were collected and tested several times during the growing season. Primers and protocols developed by Lemmetty et al. (1998) were used for IC-RT-PCR with minor modifications. The same primers and PCR protocols were used in SC-RT-PCR. However, in the last method total nucleic acids were isolated from tested plant tissue using the method described previously (Malinowski, 1997). PCR products were analysed by agarose gel electrophoresis followed by ethidium bromide staining and observation of UV fluorescence of DNA bands. Results and discussion No products were obtained in preliminary experiments with primers BRAV1/BRAV2. Positive results were observed for primers BRAV5/BRAV6. Therefore, only BRAV5/BRAV6 set was utilised in all further experiments. Positive results (detection of BRAV) were obtained with both methods used: SC-RT-PCR and IC-RT-PCR using both flowers or leaves from black currant plants showing either ETR or RTR symptoms (Fig. 1, 2).

M 1 2 3 4 5 6 7 Figure 1. Electrophoretic pattern of IC-RT-PCR products obtained with primers BRAV5 and

BRAV6 for leaves and flowers of blackcurrant plants. M – DNA 100 bp ladder, 1 – healthy leaves of ‘Titania’ cv., 2 – healthy flowers of ‘Titania’ cv., 3 – RTR symptomatic leaves of ‘Ben Lomond’ cv., 4 – RTR symptomatic flowers of ‘Ben Lomond’ cv., 5 – ETR symptomatic leaves of ‘Titania’ cv., 6 – ETR symtomatic flowers of ‘Titania’ cv., 7 – BRAV cDNA.

IC-RT-PCR method performed better than SC-RT-PCR. However, in several experiments with both methods the virus remained undetected in high percent (up to 50%) of samples collected from plants known to be infected. In one experiment results were mostly positive for flowers (8 out of 10) and mostly negative for leaves (2 out of 10) collected

23

simultaneously from the same plants. In the other case during the "blind test" virus was detected in the samples collected at one plantation but was not detected in the samples of the other cultivar collected at different field. The last case might have been a result of too narrow specificity of the primers used.

leaves flowers

1 2 3 4 5 6 M 1 2 3 4 5 6

Figure 2. Electrophoretic pattern of RT-PCR products obtained with primers BRAV5 and BRAV6 using total nucleic acids isolated by silicacapture method from leaves and flowers of blackcurrant plants showing ETR (sample 3 and 5) and RTR (sample 2 and 4). Samples 1 and 6 – healthy plants, M – DNA marker.

Therefore, on the base of this preliminary results we can conclude that RT-PCR methods of BRAV detection might already be very useful for breeders. However, at least in our hands, negative results should be verified carefully to avoid false negatives. In our opinion the methods should be further developed to achieve higher sensitivity and to ensure broad specificity. References Gajek D., Pluta S., and Zurawicz E., 1995. Perspektywy wyhodowania odmian porzeczki

czarnej odpornych na wielkopąkowca porzeczkowego (Cecidophyopsis ribis Westw.) i na rewersje. Mat. z V Ogolnopolski Zjazd Hodowcow Roslin Ogrodniczych, 23-24.02 1995, Skierniewice, Część I , pp. 199-205.

Jones A.T., Lehto K., Lemmetty A., Latvala S., Susi P., McGavin W.J, and Cox S., 1995. Blackcurrant reversion disease – tracking down the causal agent. Annual Report 1995, Scottish Crop Research Institute, Dundee, Scotland, pp. 131-134.

Latvala S., Susi P., Lemmetty A., Cox S., Jones A.T., and Lehto K. 1997. Ribes host range and erratic distribution within plants of blackcurrant reversion associated virus provide further evidence for its role as the causal agent of reversion disease. Ann. Appl. Biology. 131: 283-295.

24

Lemmetty A., Latvala S., Jones A.T., Susi P., McGavin W.J., and Lehto K., 1997. Purification and properties of a new virus from black currant; its affinities with nepoviruses and its close association with black currant reversion disease. Phytopathology 87: 404-413.

Lemmetty A., Susi P., Latvala S., and Lehto K., 1998. Detection of the putative causal agent of black currant reversion disease. Acta Hort. 471: 93-98.

Malinowski T., 1997. Silicacapture – reverse transcription – polymerase chain reaction (SC-RT-PCR): application for the detection of several plant viruses. In: Dehne et al. (eds.) Diagnosis and Identification of Plant Pathogens, Proceedings of 4th International EFPP Symposium Bonn, 9-12 September 1996. Kluwer Academic Publishers, Dordrecht. pp. 445-448.

Pluta S., and Żurawicz E., 1993 Black currant (Ribes nigrum L.) breeding programme in Poland. Acta Hort. 352: 447-453.

Pluta S., and Żurawicz E., 1998. Influence of graft-inoculation methods on the spread of two forms of reversion in black currant (Ribes nigrum L.) plants. Acta Hort. (in press)

Trajkovski V., and Anderson M. 1992. Breeding black currant for resistance to powdery mildew, gall mite and reversion disease. Report for 1990-91. Balsgard, Sweden, pp. 181-189.

Wood G.A. 1991. Three graft-transmissible diseases and a variegation disorder of small fruit in New Zealand. New Zealand J. Crop Hortic. Sci.19: 313-323.


pp. 25 - 34

25

Integrated approach for the control of American goooseberry mildew Erich Jörg1, Uwe Harzer2 and Werner Ollig2 1 Landesanstalt für Pflanzenbau und Pflanzenschutz, Essenheimerstr. 11, D-55128 Mainz 2 Staatl. Lehr- u. Forschungsanst. f. Landw.,Weinb. u. Gartb, Breitenweg 71,

D-67435 Neustadt/Wstr. (Germany) Abstract: American Gooseberry Mildew (Sphaerotheca mors-uvae(Schw.) Berk.) is the prevailing and most important disease in German gooseberry production. Recent gooseberry cropping systems are characterised by dense plantations, highly susceptible varieties, high nitrogen fertiliser input and numerous fungicide applications. As a consequence of the latter fungicidal efficacy is decreasing. An integrated approach is necessary to reduce the dependence upon fungicides. The strategy includes a modern planting system, considerable reductions in Nitrogen fertiliser dosage rates, on a limited scale the introduction of less susceptible varieties, the registration of new fungicidal active ingredients for American Gooseberry Mildew control and the combination of these new a.i. groups to an effective anti-resistance strategy. This will lead to a considerable reduction of the fungicide load of gooseberry crops and a sustainable production, which meets the consumers` and environmentalists` requirements. Key words: Gooseberry, American Gooseberry Mildew, Sphaerotheca mors-uvae, fungicides, cultivars, nitrogen fertilisation, integrated control. Introduction Gooseberry production area in Germany is about 200 to 250 ha. On about 80% of the area the cultivar “Achilles” is grown, which is highly susceptible to American Gooseberry Mildew (Sphaerotheca mors-uvae (Schw.) Berk.). On the remaining area cultivars of medium susceptibility, such as “Rote Triumph”, “Rokula”, “Invicta” or “May Duke”, are grown. American Gooseberry Mildew is the most common fungal disease in gooseberry production and of high economical importance (Müller & Gottwald, 1988). Gooseberries normally are trained and pruned as dense bushes. The average Nitrogen fertiliser input per ha and year is about 160-180 kg N. In several crops up to 200 kg N/ha and year are applied. As a consequence of this intensive input and high variety susceptibility each year severe epidemics occur which cause considerable losses either in yield or quality. For the control of American Gooseberry Mildew numerous fungicide applications are necessary. Common fungicide strategies comprise of three to four preventive treatments with sulphur (up to 5 kg a.i./ha), four to six Triforine applications until 14 days before harvest and two Azole treatments after harvest. This results in an undesirable high fungicide load of gooseberry crops. An integrated strategy including all appropriate indirect plant protection measures while minimising the direct control measures (fungicide use) is needed to improve the situation. Integrated approach In Table 1 an overview on efficient measures which may be employed to contribute to American Gooseberry Mildew control are shown. Cultivar resistance and reduced Nitrogen input are of greatest importance among the preventive measures. The fungicide schedule

26

should aim at minimising agrochemical input and the avoidance of resistance to the fungicide a. i. In the following possibilities for the establishment of an integrated control strategy are shown. Table 1. Integration of measures for American Gooseberry Mildew control

Measures Effects

Indirect/Preventive - Planting system

- Cultivar

- Fertilisation

good wind penetration ⇒ unfavourable microclimate for AMG

low susceptibility ⇒ slower epidemics, less severe

balanced nutrient supply, better ratio between sclerenchymatic and parenchymatic tissue ⇒ slower epidemics, less severe

Direct

- Pruning

- Fungicides

removal of infested tips ⇒ reduction of inoculum

keeping disease under economic threshold ⇒ avoid losses ⇒ avoid fungicide resistance by a.i. rotation

Cultivar choice As stated by Cravedi & Jörg (1996) the availability of resistant or less susceptible cultivars would solve many problems with fungal diseases in soft fruit production. Unfortunately cultivars combining high yields and desired quality properties with a low susceptibility to American Gooseberry Mildew are rare. Investigations at the beginning of the nineties revealed the cause of reduced susceptibility to American Gooseberry Mildew (Schlösser, 1990; Isachkin & Popelova, 1992). Astakhov (1989) showed that the environment strongly influences the expression of resistance to Sphaerotheca mors-uvae. Recent trials of Senst (1999) seem to confirm these findings as the cultivars “Invicta” and “Greenfinch”, which were considered to be resistant showed high disease severity on the leaves and on the fruits (“Invicta” only). It is also known that “Invicta” is highly susceptible to Drepanopeziza ribis (Keipert, 1992), a disease of major importance in Germany. Table 2 shows the main properties of several promising gooseberry cultivars and the “susceptible standard Achilles”. This cultivar is late ripening, fruits are red (desired quality property) and the fruit size in the first, second and third picking is high. From the point of harvest time (late) “Bekay” and “Rosko” may become alternatives for “Achilles”. Availability of planting material and fruit shape may slow down the introduction of these cultivars into

27

practice. “EM 1815/125”, an East Malling breed, up to now showed no mildew symptoms in Rheinland-Pfalz, but due to the fruit colour only has little chance to be accepted by the growers. The latter also holds for “Invicta” (green fruits) which will be grown only as a “niche product”. In the early and middle segment “Rokula”, “Remarka”, “May Duke” and “Rote Triumph” are cultivars which depend less on fungicides and more and more are grown. Table 2. Properties of gooseberry cultivars

Cultivar Fruit colour Fruit size Susceptibility to Am. Go. Mildew

Remark

Achilles red +++ +++ Highly susceptible to bark and stem diseases, late

Bekay red +++ + Availability of planting material? fruit shape

Invicta green ++ + / ++ Hairy May Duke

red ++ (+) ++ Early

Rosko red ++ (+) ++ Late Rokula, Remarka

red ++ (+) + (/ ++) Early

Rote Triumph

red ++ (+) ++ Hairy, uniform plant. material?

EM 1815/125

red-yellow +++ -- Late, hairy, fruit shape (“Pax-sister”)

+++ = high, ++ = medium, + = low; -- = resistant In the near future the highly susceptible cultivar “Achilles” still will be the most common cultivar but on the long run will be replaced by less susceptible ones. On short term the most promising early ripening varieties are less susceptible and offer good prospect for an integrated control of Sphaerotheca mors-uvae. Planting system The „classical“ planting system, dense bushes, is no longer advised in Rheinland-Pfalz. Instead the plants should be trained as „pillars“. This system aims at 4000 - 5000 plants per ha. Distances between the rows are 2,5 to 3 metres and plant distances within the rows should be 50 - 80 cm. Yield expectations of this cropping system in the average are 10 - 15 t/ha. The „pillar“ system allows good wind penetration which reduces the risk of American Gooseberry Mildew epidemics a bit. Fertilisation Especially in the establishing period of gooseberry orchards (the first two years) it is of significant importance to initiate a vigorous shoot growth. Therefore Nitrogen supply by no

28

means must not be the limiting factor. Later on Nitrogen fertilisation may be reduced to a certain extent. Normally along with the reduction in nitrogen a decrease of American Gooseberry Mildew can be observed. Table 3. Nitrogen fertilisation scheme of gooseberry

Basis: 100 kg N / ha* and year (max. single dosage rate: 50 kg N/ha)

Parameter Increases / Reductions kg N/ ha

Content org. material

> 4 % - 30

2 - 4 % 0

< 2 % + 20

Soil moisture

moist 0

balanced 0

dry in summer + 10

Soil cover**

high N content - 30

no cover 0

low N content - 10

Leaf fall (previous year)

late - 10

normal 0

early + 10

Shoot growth (previous year)

vigorous - 20

normal 0

poor + 30

Stone content***

0 - 30 % 0

> 30 % + 10

Maximum amount: 140 kg N / ha and year !

* = refers to the weed free strip ** = Soil cover increases mineralisation in soil. *** = of minor importance After some trials in Rheinland-Pfalz region in the south west of Germany a Nitrogen fertilisation scheme was developed which takes into consideration several important factors which influence Nitrogen availability and uptake (see Table 3). Basis is a total dosage rate of 100 kg N/ha and year. The maximum single dosage rate is limited to 50 kg, higher dosages have to be split. The maximum amount, which may be applied, is 140 kg N/ha and year. According to soil properties (content of organic matter, soil moisture content, stone content), soil cover and the crop growth in the previous year (shoot growth, leaf fall) the total amount of Nitrogen that has to be applied is increased or decreased. By using this simple scheme the grower is able to avoid superfluous fertiliser applications thus reducing American Gooseberry Mildew severity. Fungicides In Germany the fungicide schedule comprises of numerous applications (see introduction). In addition it must be stated that only two active ingredients recently (1999) are registered for the use in gooseberries, Sulphur and Lecithin. The registration of Triforine, the most commonly used a.i. has expired at the end of 1998.

29

From literature it is known that the efficacy of several fungicides strongly has decreased from the eighties on (see Table 4). This especially holds for Triforine and Triadimefon, the two a.i. most frequently used for the control of Sphaerotheca mors-uvae. On the other hand modern fungicides (2nd generation azoles, strobilurines, Quinoxyfen) showed good efficacy over longer periods.

Table 4. Efficacy of fungicides against American Gooseberry Mildew

Nielsen & Kirknel (1986)

Triadimefon insufficient results

Jorgensen et al. (1987)

Benzimidazoles unacceptable results

Goszczynski et al. (1988)

Triadimefon a strain less sensitive

Hughes & Wilson (1988)

Pyrifenox 100% control

Nowacka et al. (1990)

Triadimefon Pyrifenox Flusilazole Penconazole

“very effective”

LPD (1990) Triforine Flusilazole

efficacy 60 % efficacy 99 %

Cimanowski & Goszczynski (1992)

Flusilazole Bupirimate Difenoconazole

effective, long inhibition of viable spores

Cimanowski et al. (1995)

Triadimefon Flusilazole

4 treatments “best results”

Krüger (1992) Triadimefon

efficacy 8 %

Jung (1999) Triforine Quinoxyfen Kresoxim +Fenpropimorph

efficacy 28 % efficacy 88 % efficacy 97 %

The governmental crop protection service of Rheinland-Pfalz carried out several fungicide trials on American Gooseberry Mildew in order to enhance the registration of new fungicidal a.i. for gooseberry, to develop an anti-resistance strategy and to reduce the fungicide load of the crop. The trials are briefly described in Table 5 and the results are shown in Figures 1 – 3. As a worst case the susceptible cultivar ”Achilles” was used for the trials and the new a.i. (Kresoxim-methyl, Quinoxyfen) were compared to the standards Triforine and Triadimefon. Results for the efficacy of Kresoxim-methyl and Quinoxyfen are very promising. American Gooseberry Mildew was controlled insufficiently by the standards (Triforine and Triadimefon). Efficacy was 20-25 % in 1996, 20-50 % in 1997 and 35 % in 1998 (Fig. 1 - 3). Bion. a resistance activator completely failed in 1996 (Fig. 1) , and thus was no longer included in the trials. Penconazole reached an efficacy of 50 %, which also is not satisfying (Fig. 1). In all three years Kresoxim-methyl controlled the disease by more than 90 %. The

30

lowest concentration of 0,0125 % proved to be sufficient. In 1998 Quinoxyfen was tested and gave even better results than Kresoxim-methyl (Figure 3). For an anti-resistance strategy rotations of the fungicide from the different groups are very important. As may be seen from Fig. 3 fungicide schedules including Kresoxim-methyl, Quinoxyfen and Triforine gave very good results, irrespective of the sequence of application of the a.i.. Only three treatments were necessary to keep Sphaerotheca mors-uvae on an insignificant severity level. Table 5. Control of American Gooseberry Mildew, Trials (1996-1998)

1) Crop -Location: Neustadt/Pfalz -Cultivar: Achilles (highly susceptible) -Year of planting: 1994

2) Fungicides

Product active ingredient Group Conc. %

Saprol Neu Triforine SBI 0,15 %

Bayfidan Sp. WG Triadimefon SBI 0,05 %

Omnex Penconazole SBI 0,025 %

Bion Acibenzola-S-methyl

Res. activator 0,005 %

Discus Kresoxim-methyl Strobilurin 0,0125-0,03 %

Fortress Quinoxyfen Chinoline 0,03 %

Water: 1000 l/ha SBI-fungicides (Triforine, Triadimefon, Penconazole) should further be included into the fungicide strategies because of two reasons: to avoid resistance of the fungus and for the control of Drepanopeziza ribis which also is very common. Efficacy of Kresoxim-methyl and Quinoxyfen on this fungus is very poor. As negative side-effects on beneficial organisms of both a.i. never could be detected there seems to be no obstacle to an inclusion into integrated control strategies Conclusion: conventional vs. integrated control With regard to the fungicide load of gooseberry crops a considerable reduction is possible (Fig. 4). Whereas conventional fungicide schedules rely on sulphur and SBI-fungicides only in an integrated schedule fungicides from four different groups can be applied. Taking into consideration a lower cultivar susceptibility, less favourable microclimate within the crop (training system) and less favourable nutrition basis (less Nitrogen fertilisation) one may reduce the number of applications from about 12 to at maximum 6 or probably less treatments. This will result in a reduction in the amount of products applied from 24 kg/ha and year to 6 kg/ha and year (Fig. 4). For the a.i. the reduction is from 14 kg/ha and year to 4 kg/ha and year.

31

Untr.Saprol Neu

BayfidanOmnex

DiscusBion

0

20

40

60

80

100

%efficacy (Abbott)diseased shoots

Treatments: 24.04. / 07.05. / 20.05. / 05.06. / 18.06.

(0,15%)(0,05%)

(0,025%)(0,03%)

(0,005%)

Cv.: Achilles

Figure 1. Control of American Gooseberry Mildew 1996 in Rheinland – Pfalz

Untr.Saprol Neu

Bayfidan Sp. WGDiscus

Discus0

20

40

60

80

100


Treatments: 12.05. / 26.05. / 04.06. /12.06.(only Saprol Neu/ Bayfidan Sp. WG)

(0,15%)(0,05%)

(0,0125%)(0,02%)

Cv.: Achilles

Figure 2. Control of American Gooseberry Mildew 1997 in Rheinland - Pfalz

32

0

20

40

60

80

100


Treatments: 11.05. / 21.05. / 04.06.

(0,15%)

(0,0125%)

(0,03%)

Cv.: Achilles

Saprol NeuDiscus

Fortress1.Fortress2.Discus3.Saprol Neu

1.Discus2.Saprol Neu3.Fortress

Figure 3. Control of American Gooseberry Mildew 1998 in Rheinland – Pfalz

Fungicides active ingredients0

5

10

15

20

25kg/ha

conv. integr. Conventional: -Sulphur +SBI Nu.Appl.: 12

Integrated: -Sulphur +SBI +Strobilurine +Quinoxyfen Nu. Appl.: 6

Figure 4. Fungicide load of gooseberry crops

33

References Astakhov, A.I. (1989): Black currant genetics and breeding. III. Analysis of the genotype of the

variety Brodtorp and the effect of the environment on the expression of resistance to American mildew. Genetika-Moskva 25, 9: 1599-1605.

Cimanowski, J. and W. Goszczynski (1992): The influence of fungicides on the sporulation of apple powdery mildew (Podosphaera leucotricha (Ell. et Ev.) and gooseberry American Mildew (Sphaerotheca mors-uvae (Schw.) Berk. et Curtis). Fruit Science Reports 19 (2): 89-93.

Cimanowski, J., Rejnus, M. & A. Bielenin (1995): Effectiveness of systemic fungicides used in different programmes in the control of black currant diseases. Journal of Fruit and Ornamental Plant Research 3 (4): 177-186.

Cravedi, P. & E. Jörg (1996): Special challenges for IFP in stone and soft fruit. IOBC/wprs Bulletin 19 (4): 48-56.

Goszczynski, W., Cimanowski, J. & R. Bachnacki (1988): First note on the occurrence of a strain of Sphaerotheca mors-uvae (Schw.) Berk. with decreased sensitivity to Triadimefon. Fruit Science Reports 15 (4):, 181-184.

Hughes, A. & D. Wilson (1988): Development of Pyrifenox for control of foliar diseases on apples and black currants in the UK. Brighton Crop Protection Conference. Pests and Diseases 1988 Vol. 1: 223-228.

Isachkin, V.A. & E.A.Popelova (1992): Inheritance of resistance to Sphaerotheca mors-uvae in the progeny of Ribes canadensis Jancz. Izvestiya Timiryazevskoi Sel`skokhozyaistvennoi. Akademii, No.2: 50-56.

Jorgensen, L.N., Nielsen, B.J., Petersen, E.F. & H. Elbek-Petersen (1987): Fungicide resistance. Present situation and fungicide strategies for Benzimidazoles in Denmark. Växtskyddsrapporter 48: 59-69.

Jung, R. (1999): Bekämpfung von Stachelbeermehltau und Botrytis. Obstbau 4/1999: 218-219. Keipert, K. (1992): Gegen Krankheiten und Schädlinge weniger anfällige Obstsorten für Erwerbs-

anbau und Selbstversorger. April 1992, Aussendung LWK Rheinland, S. 10-11. Krüger, E. (1992): Biologische Produkte – eine Alternative bei der Bekämpfung des Stachelbeer-

mehltaus. Erwerbsobsbau 34 (1): 8-12. LPD (1990): Versuchsbericht des Pflanzenschutzdienstes Rheinland-Pfalz. Müller, R. & R. Gottwald (1988): Schaderregerauftreten und Möglichkeiten der Bestandes-

überwachung in Johannis- und Stachelbeeren. Nachrichtenblatt Pflanzenschutzd. DDR 42 (8): 160-163.

Nielsen, S.L. & E. Kirknel (1986): Mist spraying with low spray volumes and reduced dosages of pesticides against American Mildew (Sphaerotheca mors-uvae) and rust (Cronartium ribicola) on black currant (Ribes nigrum). Tidsskrift for Planteavl. 90 (4): 377-384.

Nowacka, H., Cimanowski, J., Bachnacki, R. & J. Brozbar (1990): Evaluation of several new fungicides for the control of black currant diseases. Fruit Science Reports 17 (3): 149-154.

Schlösser, E. (1990): Horizontal resistance of some plant species to powdery mildew. Meded. Fac. Landbouww. Rijksuniv. Gent 55 (2a): 203-206.

Senst, A. (1999): Mehltauresistenz bei Stachelbeeren. Obstbau 4/1999: 219-221.

34


pp. 35 - 40

35

A system for managing Botrytis and powdery mildew of strawberry: first results 1A M Berrie; D C Harris and Xiangming Xu, 2C M Burgess 1Horticulture Research International – East Malling, West Malling, Kent, ME19 6BJ, UK 2Horticulture Research International – Efford, Lymington, Hants, SO41 0LZ, UK Abstract: A mathematical model (BOTEM), describing the influence of weather and Botrytis inoculum on flower infection in strawberry, was incorporated into a management system to assist in decisions on sprays to control Botrytis fruit rot and powdery mildew in main season strawberry crops. Decision on mildew sprays were based on the incidence of cleistothecia in the crop the previous autumn. The management system was evaluated for the first time in a large replicated field experiment on strawberry cv. Elsanta. The incidence of powdery mildew and Botrytis fruit rot, in plots sprayed according to the management system, was compared to that in plots sprayed routinely or left untreated. No mildew was recorded before or during harvest in any plots and the incidence of Botrytis fruit rot at harvest was negligible in both treated and untreated plots. Up to 27% Botrytis fruit rot developed in fruit from untreated plots seven days after harvest in post harvest tests. All the spray treatments reduced the incidence of Botrytis fruit rot in post-harvest tests, but this was achieved with up to 60% reduction in fungicide inputs in the managed plots. Further field evaluation is required before the management system is finalised. Key words: disease warning system, fungicide, cleistothecia. Introduction Botrytis is one of the most important diseases of strawberry, reducing yield and quality pre- and post-harvest. Current control measures rely on the use of intensive fungicide spray programmes, which are applied near and during harvest. However, despite these sprays, control can still be poor when weather conditions are warm and wet and favour Botrytis. There is, therefore, a need to explore new approaches to disease management. For these to be acceptable, they must be effective in controlling Botrytis, minimise fungicide use, integrate with control of other diseases especially powdery mildew (Sphaerotheca macularis), maintain fungicide efficacy by avoiding the development of fungicide resistance and, most important, be practical. The use of disease warning systems provide one alternative approach to the routine use of fungicides for control of Botrytis. Disease warning systems based on weather do not forecast infection since the weather cannot be predicted with any degree of accuracy. They only indicate that infection has occurred. Therefore, for such systems to be of use in disease management there must be fungicides available that can eradicate infection after it has occurred, as well as provide protection and act to suppress sporulation. A number of fungicides active against Botrytis are approved for use on strawberries in the UK. However little is known about their mode of action as eradicants protectants or antisporulants. The main objectives of the work described below were (a) To develop a disease warning system for Botrytis on strawberry; (b) To identify the mode of action of fungicides active against Botrytis; (c) To develop a management system for powdery mildew on strawberry and (d) To test in field trials the combined Botrytis/powdery mildew management system developed.

36

Materials and methods Disease warning system for Botrytis on strawberry The methods used to develop the mathematical model describing the influence of weather and Botrytis inoculum on flower infection in a strawberry crop have been described previously (Berrie et al., 1998). The Botrytis warning system (BOTEM) developed is PC-based and gives warnings of Botrytis infection during flowering. The model is driven by weather variables including day-time vapour pressure deficit and night-time temperature. These variables were recorded in the crop by a weather station (METOS, Pessl, Weiz, Austria or Skye Minimet, Skye Instruments Llandrindod Wells, Wales) and downloaded to a PC. The model output is displayed graphically (Fig. 1) and shows estimated % flower infection, the predicted % fruit infection resulting from the flower infection and the inoculum potential. The initial action threshold,chosen for the warning system, was reached when the predicted fruit infection increased to 10% or more. Fungicide mode of action The curative action of fungicides active against Botrytis cinerea (Tab. 1) was investigated in the laboratory using strawberry leaf discs. Leaf discs, which had been inoculated with B. cinerea two days earlier, were immersed in the test fungicide and then incubated under UV light in Petri dishes, maintained at 99% relative humidity to favour growth and sporulation of B. cinerea. The discs were assessed for B. cinerea two weeks later. The antisporulant action of the fungicides was similarly tested except that the leaf discs were treated with fungicide 12 days after inoculation with B. cinerea. Leaf discs dipped in water or undipped were included as controls in both experiments. Table 1. Effect of fungicide treatment on Botrytis sporulation when applied 2 days after

inoculation (Experiment 1) or 12 days after inoculation (Experiment 2)

Mean % leaf disc area with sporing Botrytis

Fungicide treatment (product) Experiment (1) (Curative action)

Experiment (2) (Antisporulant action)

azoxystrobin (Amistar) carbendazim (Bavistin) chlorothalonil (Bravo) dichlofluanid (Elvaron) tebuconazole (Folicur) KIF 3535 (Experimental) iprodione (Rovral WP) pyrimethanil (Scala) tolylfluanid (Euparen) fenhexamid (Teldor) Untreated Water

3.0 0 0

0.1 16.3

0 0

4.3 8.3 9.0 5.7 13.7

16.5 1.7 0

26.5 43.2 43.0

0 42.4 10.0 11.3 43.8 39.1

37

Management system for powdery mildew on June-bearers A preliminary system for managing powdery mildew on June-bearer strawberries was developed from the results of previous research on cv. Elsanta (Berrie & Burgess, 1997, Berrie et al., 1998). These results are summarised as follows: (1) Post-harvest epidemics of powdery mildew have no significant effect on the yield in the

following season on strawberry cv Elsanta. (2) In recent seasons, under the weather conditions in the UK, strawberry plants continue to

grow slowly throughout the winter whereas the post-harvest mildew epidemic ceases once the temperature falls in the autumn. Consequently leaves infected with mildew in the autumn have senesced and died by the following spring and are therefore not important usually in initiating new mildew epidemics the following spring.

(3) Cleistothecia appear to play a part in the epidemiology of powdery mildew and ascospores released from them in the spring are probably responsible for initiating early mildew epidemics.

Therefore, the need to apply sprays for control of powdery mildew on cv Elsanta can be determined by the presence of cleistothecia in the crop the previous autumn. Where inspection of the crop in autumn reveals they are present, protectant sprays to control mildew are required the following spring. If no cleistothecia are found, then no sprays are required in spring. Table 2. Treatment programme for strawberry disease management trials 1999.

Botrytis

Powdery Mildew

Treatment

Decision/Timing Fungicide Decision/Timing Fungicide 1. Untreated – – – – 2. Routine Flowering – 10 day

programme from white bud/first flower Fruit 7-10 day programme

Elvaron

Bravo, Scala Teldor

Flowering – 10 day programme from white bud/first flower Fruit 7-10 day programme

Corbel, Sys-thane,

Rubigan

Systhane, Nimrod

3. BOTEM – 1 Flowering – Fungicide sprays applied only in response to BOTEM risk Fruit – Fungicide sprays applied only in response to BOTEM risk

Rovral alternating with Bravo

Rovral alternating with Bravo or

Teldor

Flowering – Mildew monitored. Only spray if seen. Fruit – Spray only if mildew seen.

Systhane

Nimrod

4. BOTEM – 2 Flowering – Sprays applied in response to BOTEM risk, but routine spray at 30% - full flower if no sprays applied previously or long interval (>14 days) since last spray. Fruit – Routine programme


Routine spray-

Elvaron

Bravo, Scala Teldor

Flowering – Monitor mildew spray when first seen or when spray for Botrytis. Routine spray at 30% - full flower as for Botrytis. Fruit – Routine programme

Systhane

Systhane

Nimrod

5. BOTEM – 3 Flowering – Fungicide sprays applied only in response to BOTEM risk. Fruit – Routine programme


Bravo, Scala Teldor

Flowering – Monitor for mil-dew. Spray when first seen or when first spray for Botrytis. Fruit – Spray when spray for Botrytis.

Systhane

Nimrod

38

Field evaluation of the Botrytis/powdery mildew management system The management system was evaluated in strawberry crops cv Elsanta at three sites – at HRI–East Malling, HRI–Efford and on a commercial fruit farm in Kent. Three management programmes were tested and compared to a conventional routine programme and an untreated control. The plots contained four beds each consisting of a double staggered row of 12 plants. A latin square experimental design was used. The criteria used to make decisions in the management programmes are given in Table 2. In two programmes (BOTEM 1 and 3) fungicides (iprodione or chlorothalonil, alternating to minimise the risk of resistance) were only applied for Botrytis control in response to infection risks identified by the model. The third programme (BOTEM 2) was designed to reduce the risk of Botrytis infection posed by the first two programmes should application of a curative treatment be prevented by weather conditions. In this programme a routine spray of dichlofluanid would be applied at 30% flowering if a treatment had not yet been applied. The criteria for treatment for powdery mildew were based on the incidence of cleistothecia in the crop the previous autumn. During fruiting and harvest, the programmes BOTEM 2 and 3 would revert to the routine spray programme. Weather data was monitored in the crops by either a METOS or Skye automatic weather station. The crops were monitored twice weekly for powdery mildew. The fruit was harvested twice weekly and the incidence of Botrytis rot and powdery mildew recorded. In addition, at each harvest, 50 fruits per plot were incubated in damp chambers to allow development of latent infection of Botrytis. The incidence of Botrytis was assessed seven days after harvest. Table 3. Treatment applied and Botrytis control achieved in strawberry using three different

management programmes compared to a routine spray programme.

No. of Sprays % Botrytis rot in post-harvest tests date assessed

Treatment Spray Target

Flowering Fruiting/harvest

2/6 8/6 11/6 15/6 18/6 22/6 25/6 Mean

Untreated Mildew Botrytis

0 0

0 0

20.4 3.6 10.4 7.6 27.2 13.9 0.8 12.0

Routine Mildew Botrytis

4 3

5 5

0.8 0.4 0.8 0 6.3 0 0.4 1.2

Programme BOTEM 1

Mildew

Botrytis

0

2

1

2

8.8 0 6.0 3.6 5.5 1.2 0 3.6

Programme BOTEM 2

Mildew

Botrytis

2

2

5

5

10.8 0 1.6 0.4 4.0 0 0.9 2.5

Programme BOTEM 3

Mildew

Botrytis

2

2

5

5

6.8 0 1.2 0.8 3.0 0 0 1.7

Results and discussion Fungicide mode of action The best curative action was shown by carbendazim, chlorothalonil, iprodione, azoxystrobin and KIF 3535 (Tab. 1). Carbendazim, chlorothalonil and iprodione showed good antisporulant action. Tolylfluanid and fenhexamid also had antisporulant action. Iprodione and

39

chlorothalonil were selected for use in the Botrytis management trials. These were used in an alternating programme to minimise the risk of fungicide resistance. Carbendazim was not included because of the high risk of fungicide resistance. The testing of the fungicides for mode of action has so far only been conducted in small-scale tests in the laboratory. Further testing in the field is required to confirm the results. Field evaluation of the Botrytis/powdery mildew management system Only the results from the trial at East Malling are reported here. The risk of Botrytis during flowering was relatively low (Fig. 1). Consequently, fewer sprays were applied in the management programmes compared to the routine (Tab. 3). The incidence of Botrytis rot at harvest was negligible. However, the incidence of Botrytis in the post-harvest tests was higher with up to 27% of the fruit developing the rot in untreated samples. All the sprayed treatments reduced rot incidence (Tab. 3). Figure 1. Predicted development of Botrytis on strawberry No cleistothecia were observed in the crop the previous autumn and no mildew was observed in any of the plots prior to harvest. No powdery mildew was recorded on the fruit. The initial results from using the management system, including BOTEM, to assist in decisions on fungicide use are promising. Similar control of Botrytis compared to the routine sprayed plots was achieved, but with reduced fungicide inputs. The criteria used to make decisions on the need for control of powdery mildew were also successful. However, these are only preliminary results and further testing is still required before the system can be released commercially. The main areas that need to be addressed are as follows: (1) The action threshold (currently 10% predicted fruit infection) used in the Botrytis warning

system. (2) The practical use of the Botrytis risk information. (3) The implications of reduced fungicide inputs for control of other diseases such as

Colletotrichum acutatum. (4) The choice of fungicides for use with the management system.

40

Acknowledgements

The authors wish to thank the Ministry of Agriculture, Fisheries and Food and the Horticultural Development Council for funding the work.

References Berrie, A. M. & Burgess, C. M. 1997: The effect of post-harvest epidemics of powdery

mildew on yield and growth of strawberry cv Elsanta. Acta Hort. 439 (2): 791-798. Berrie, A. M.; Harris, D. C.; Xu, X. M. & Burgess, C. M. 1998: Progress towards integrated

control of Botrytis and powdery mildew of strawberry in the UK. IOBC/WPRS Bulletin 21 (10): 95-102.


pp. 41 - 46

41

Occurrence and spread of strawberry anthracnose caused by Colletotrichum acutatum in Austrian strawberry fields – experiences from laboratory, greenhouse and field Robert Steffek, Josef Altenburger BFL, Federal Office and Research Centre for Agriculture; Institute for Phytomedicine Spargelfeldstraße 191; A-1226 Vienna, Austria Abstract: 1997 the incidence of anthracnose spots on strawberry fruits and runners was observed for the first time in Austria, two isolates were confirmed as Colletotrichum acutatum in 1998. 1999 the disease occurred in three Austrian strawberry regions. In laboratory and greenhouse trials the side effect of two recently registrated botryticides: Teldor (a.i. Fenhexamid) and Switch (a.i. Cyprodinil and Fludioxonil) on Colletotrichum was tested. In laboratory both a.i. reduced the in-vitro growth of C. acutatum and were more effective in inhibiting in vitro growth than Euparen (a.i. Dichlofluanid). In greenhouse protective sprays 3 days before an infection period gave better results than curative sprays (18 hrs and 3 days after inoculation); protective sprays of Teldor were less effective than Switch and Euparen. Dipping strawberries in B. subtilis solution before planting reduced the number of diseased fruits, in laboratory B. subtilis (conc. >105 spores/ml PDA) inhibited the mycelial growth totally. In the field spray schedules to control botrytis gave no sufficient control of Colletotrichum in strawberry plantations who were latent infested. Key words: Colletotrichum acutatum, Fragaria x ananassa, anthracnose, strawberry Introduction Anthracnose of strawberries can be caused by C. gloeosporoides, C. fragariae and C. acutatum. 1998 isolates gained from two infested plants of two Austrian strawberry regions were confirmed by its morphological (paraquat method, Hughes et.al. 1997) and serological characteristics as Colletotrichum acutatum. This was the first recording of Colletotrichum on strawberries in Austria. The disease causes a rot of ripening fruits as well as anthracnose symptoms on runners and stalks. Early infections can lead to flower blights. Since the fungus can survive in a quiescent state these symptoms might not be visible on the nursery plants. Although Colletotrichum acutatum is a quarantine pest and planting material has to be free from the pathogen, the most important source for the dissemination of the disease is the trade of latent infested planting material.

Result of laboratory, greenhouse and field trials give an overview of the ability to control the fungi. Various fungicides are described to be effective against Colletotrichum: Benomyl, Mancozeb and Chlorothalonil (Agrios, 1997), Prochloraz-Mn, Difenoconazol and Propiconazol (Freeman, 1997). In extension service publications Dichlofluanid and Thiram are recommended (SOV, 1998). With the exception of Dichlofluanid these fungicides described as effective are not registrated for the use in strawberries in Austria.

Aim of our trials was to test the side effect of two recently registrated botryticides: Teldor (a.i. Fenhexamid) and Switch (a.i. Cyprodinil and Fludioxonil) on Colletotrichum. Both fungicides were tested in laboratory and greenhouse and compared to other fungicides registrated in strawberries. In addition the use of the antagonist Bacillus subtilis for the biological control of Colletotrichum on strawberries was tested.

42

Methods Laboratory For the laboratory trials we used Petri-dishes (2% PDA) containing 10; 1; 0,1 and 0,01 µg a.i/ml PDA of the fungicides: Teldor (Fenhexamid: 51% a.i.), Switch (Cyprodinil 37,5% and Fludioxonil 25%), Euparen (Dichlofluanid (50%), Benlate (Benomyl 50%), Dorado (Pyrifenox 20%), Rovral (Iprodione 50%), Ronilan (Vinclozolin 50%) and FZB 24 WG (Bacillus subtilis)1.

5 mm mycelium disks of two different isolates of C. acutatum2 collected from infested plants in field were transferred to the petri dishes. After 7/14 days of incubation at 20°C (16 hours light/8 hours dark) the radial growth was measured and compared to the untreated control.

Greenhouse Two trials were designed: potted plants of cv. Elsanta (4 replicates; 10 plants/replicate)

a) Teldor, Switch, Euparen and Dorado were sprayed 7 resp. 3 days before an artificial inoculation and compared to sprays 18 hours resp. 3 days after inoculation in order to test the protective and curative activity of the fungicides . In one variant plants were dipped in B. subtilis1)-solution before planting and watered 4 days after planting with the same solution. The artificial inoculation was conducted at BBCH 81 (white fruits) with a mixture of both Colletotrichum isolates containing 5x105 spores/litre. To facilitate infection the growth chamber was kept at a humidity of 100% for 18 hours after inoculation.

b) The plants were dipped in a Colletotrichum acutatum solution (5x105 spores/litre) before potting. Fungicide treatments at different growth stages and intensities should show, how sporulation and symptoms can be suppressed in infested plants. Field

Field trials with artificial inoculation were not conducted to avoid any further dissemination of the quarantine pathogen. 1999 we received Colletotrichum-infested samples from farms of three different strawberry-growing-regions in Austria. Together with local advisors and strawberry-growers the used spraying schedules and possible preventive measures were discussed. Results Laboratory For both isolates similar results were received. Figure 1 shows the reduction of the mycelial growth of the Colletotrichum acutatum isolate S in % at different concentrations (a.i.) . In a pilot test Ronilan and Rovral were not effective at a level of 10 µg a.i./ml. No detailed trials were carried out with these DMI-fungicides.

Teldor and Switch reduced the in-vitro growth of C. acutatum, both fungicides were more effective in inhibiting in-vitro growth than Euparen. B. subtilis inhibited the growth of C. acutatum at concentrations >105 spores/ml PDA completely.

1 The recommended dosage of FZB 24 WG for potato seed tubers: 1g (=5x1010 spores) per liter was used for dipping and watering in greenhouse. In the laboratory trials the petri-dishes contained: 105, 106, 107 resp. 108 spores/ml PDA. 2 Isolate S taken from an infested fruit of a strawberry field in Styria, Isolate B taken from a lesion on a runner of plants received from a farm in Burgenland.

43

1

Figure 1: Results of laboratory trials: reduction of mycelial growth in % Greenhouse Trial a) After inoculation and an 18 hours infection period 65 % of the fruits of the untreated control developed typical symptoms. From more than 90% of the infested fruits isolate S was re-isolated (isolate B <10%). The reduction in the treated plots is shown in figure 2. Figure 2: Results of a greenhouse trial The results indicate that protective sprays 3 days before infection period gave better results than curative sprays immediately (18hrs) after the infection period. Later sprays (3d) were inefficient. The protective efficacy of Switch and Euparen was higher than the one of

0

10

20

30

40

50

60

70

80

90

100

0,01µg a.i./m l Agar 0,1 µg a.i./m l Agar 1 µg a.i./m l Agar 10 µg a.i./m l Agar

Red

uctio

n of

radi

al g

row

th % Sw itch

Te ldorDoradoEuparenBenlateBac.subtilis

0

10

20

30

40

50

60

7d-prot 3d-prot 18hrs-cur 3d-cur dip-planting

Effic

acy

%

EuparenDoradoSw itchTeldorB.subtilis

44

Teldor. Pyrifenox was inefficient. Dipping and watering the plants with B. subtilis reduced the number of diseased fruits by 31%.

Trial b) The field of trial b could not be carried out. After infection the potted plants did not take root and wilted shortly after planting. From cross-sections of the attacked crown Colletotrichum acutatum (as well as Fusarium sp. and Alternaria sp.) was re-isolated. Field Experiences from strawberry farmers showed that the most common spray schedule to control botrytis (3 sprays during blossom) gave no sufficient control of Colletotrichum once the strawberries were infested. In several fields we observed high losses in yield that were not influenced by the fungicides (DMI, Euparen, Switch, Teldor) applied during blossom. Discussion The laboratory trials showed that both new botryticides (Switch, Teldor) reduced the growth of Colletotrichum acutatum. In greenhouse the protective activity of Teldor is less than the one of Euparen and Switch. With the new botryticides side effects on the pathogen in the field can be expected in order to reduce the spread of the disease when only a limited number of plants are infested.

Some fungicides were not efficient in our trials: the DMI-fungicides Rovral and Ronilan (tested only in laboratory) and the EBI-pyridin Dorado (in laboratory and in green house). Other EBI-fungicides from the chemical groups imidazole and triazole were reported to be effective against Colletotrichum (Freeman, 1997).

The application of Bacillus subtilis in greenhouse lead to a reduction of diseased fruits. The antagonistic effect on C. acutatum was shown in-vitro. Further trials are needed to find out whether the use of B. subtilis in the field might be beneficial for plant health and an alternative to fungicide treatments.

It is evident that under favourable climatic conditions (temperatures > 20°C, high humidity) in the field the control of plantations that are (latent) infested with Colletotrichum by chemical means is very difficult. In such cases fungicide sprays twice a week from early blossom stage until harvest (Howard et.al., 1992) resp. expansion of the spraying period from beginning of fruit stalk growth until end of blossom (SOV, 1998) are recommended.

To avoid intensive spray schedules it is essential for the farmers to acquire healthy transplants. Since the disease can hardly be detected visually on planting material rapid and accurate methods for the detection of the pathogen such as the paraquat test and serological tests with monoclonal antibodies have to be used to monitor the health of plant materials (COOK, 1993). However it is a problem that the control of every single import is not feasible within the EU-market and the controls at the nurseries seem to be not efficient enough.

In long-terms Colletotrichum acutatum might play an increasing role as pathogen on strawberries. Therefore the suitability of resistant varieties as well as strategies to reduce the inocullum density on plant debris in the spring and the dissemination of the inocullum in the field during the season should be evaluated. References Agrios G. (1997): Plant pathology (4th edition). Academic press, 329-331. Cook R.T.A. (1993): Strawberry black spot caused by Colletotrichum acutatum. In: Plant

health and the European single market. BCPC Monograph No. 54: 301-304.

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Eastburn D.M. and Gubler W.D. (1990): Strawberry anthracnose: Detection and survival of Colletotrichum acutatum in Soil. Plant Disease 2: 161-163.

Freeman S. et.al. (1997): Control of Colletotrichum in strawberry under laboratory, greenhouse and field conditions. Plant disease 81 (7): 749-752.

Howard M.H. et.al. (1992): Anthracnose of Strawberry caused by the Colletotrichum complex in Florida. Plant Disease 76 (10): 976-981.

Hughes K.J.D. et.al. (1997): Development of a rapid method for the detection and identification of Colletotrichum acutatum. In: Dehne H.W. et.al. (ed.): Diagnosis and identification of plant pathogens, 113-116; Kluwer Academic Publishers, Dordrecht.

SOV (1998): Handbuch Beeren. Ed: Schweiz. Obstverband, Eidg. Forschungsanstalt Wädens-wil und Changins und Forschungsinstitut für biologischen Landbau.

Steffek R. and Persen U. (1998): Erstmaliges Auftreten von Colletotrichum im österreichischen Erdbeeranbau. Besseres Obst 04/98: 16-17.

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pp. 47 - 51

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Effectiveness of different methods of blackcurrant gall mite control (Cecidophyopsis ribis Westw.) and their influence on population of phytoseiid mite and two-spotted spider mite Dariusz Gajek, Edmund Niemczyk, Małgorzata Sekrecka Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland Abstract. The blackcurrant gall mite (C. ribis Westw.) is the most important pest of blackcurrants in Poland. Effectiveness of different methods of its control (chemical and mechanical) was studied. It was ascertained that removal of infested buds combined with two treatments with endosulfan or three treatments with endosulfan alone gave the best control of the gall mite. Endosulfan applied once, twice or three times during bloom was selective to phytoseiid mites - which occurred in a high number - while kept population of two-spotted spider mite on a very low level. It was also observed that sprayings with endosulfan reduced effectively aphid population. Key words: black currant, gall mite, endosulfan, phytoseiid mite, two-spotted spider mite Introduction Blackcurrant has been an important soft fruit crop in Poland since early eighties, when its profitability was very high. At present the total acreage of this crop is estimated as 20-25 thousand hectares but its profitability changes from year to year. This causes that the growers alternate plant protection strategy according to price for the fruits. In some seasons almost all chemical treatments are abstained. This resulted in a strong spread of pests and diseases, especially blackcurrant gall mite and reversion. In consequence the yield decreases and expenditures for restoration planting suddenly increase. Both phytophages mentioned above – the gall mite and reversion – constitute the most important problems in blackcurrant protection (Gajek 1997, Gajek & Boczek 1998). There are three pesticides registered for the gall mite control in Poland: endosulfan, carbosulfan and amitraz. Among them the first one is most effective. According to the actual programme of plant protection it is recommended to perform three treatments with this insecticides per season: at the beginning of the bloom, during the full bloom and at its end (Program Ochrony Sadów i Krzewów Jagodowych 1998) IOBC Guidelines for Integrated Production of Soft Fruits (Jörg & Cross, 2000) permits only two treatments with endosulfan on blackcurrants per a season, and only for the gall mite control. According the same IOBC Guidelines additional, mechanical method for a control of this pest is required: „Black currant crops must be closely inspected for black currant gall mite galls during the dormant period when they are easily visible and all infested plant material must be removed from the plantation and destroyed.” The study on this subject was conducted in 1998-99. Its aim was to estimate the effectiveness of chemical and mechanical methods of the gall mite control. Additionally, influence of control methods applied on population of phytoseiid mite, two-spotted spider mite and aphids was studied.

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Materials and methods The experimental planting used for the study covered an area of about 0.2 ha and consisted of 6 blackcurrant rows with cultivars ‘Ojebyn, ‘Titania’ and ‘Ben Lomond’. Each row consisted of 10 replications with 5 blackcurrant bushes. The replications were separated by 2-m gasps. The rows were divided across into 5 plots, so each plot consisted of 12 replications. Treatments against the gall mite The treatments are summarised in Table 1. A hand removal of infested buds on plots 1, 2 and 3 was conducted during early spring. On the plot 4 (three treatments with endosulfan) the infested buds were counted but not removed. On the plot 5 the buds were not removed and no treatment with endosulfan was applied. Mite’s population Population of the phytoseiid mite and two-spotted spider mite was determined three times in each season. The sample unit consisted of 20 leaves and 12 such units were collected from each plot at each survey term. The number of the mobile stages of the pest and the phytoseiid specimens was examined under stereomicroscope. Collected phytoseiid were fixed in Hoyer solution and then the predatory mites were specified. Aphids infestation Intensity of aphid’s infestation was determined at the beginning of June 1998. The number of aphid colonies was counted on all replications. Table 1. Data of treatments

Beginning of flowering

Full flowering

End of flowering Plot 24.IV

199826.IV1999

30.IV1998

30.IV 1999

7.V 1998

4.V 1999

1. Removing of infested buds 2. Removing of infested buds + 1 x endosulfan 3. Removing of infested buds + 2 x endosulfan 4. 3 x endosulfan 5. Check (untreated)

– – + + –

– – + + –

– + + + –

– + + + –

– – – + –

– – – + –

Results and discussion Effectiveness of the gall mite control Before treatments in 1998 the intensity of the blackcurrant infestation with the pest was very heavy - from more than 6 infested buds per one bush on the check plot to more than 20 infested buds per one bush on the plot 1 (Tab. 2). There were significant differences in the gall mite infestation between experimental plots. Infestation level after treatments distinctly changed. It was observed that on the check plot and on the plot where only the infested buds were removed the pest number increased. On the other three plots infestation level was a little lower (plot 2 – removal of infested buds and 1 treatment with endosulfan) or much lower (plot 3 – removal of infested buds and 2 treatments with endosulfan and plot 4 – three endosulfan treatments).

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These results were not easy for interpretation, so Henderson-Titlon formula (Podręcznik doświadczalnictwa polowego w ochronie roślin 1981) was used for estimation of the efficacy of control methods applied (Tab. 2). Obtained results showed that the removal of infested buds combined with 2 treatment with endosulfan (plot 3) and three treatments with endosulfan (plot 4) gave the best control of the blackcurrant gall mite. The significantly lower effect was obtained on the plot 2 where removing of infested buds was combined with one endosulfan treatment. Removal of infested buds without chemical control (plot 1) was least effective. Table 2. Efficacy of different methods of blackcurrant gall mite control

Average number of infested buds per 1 bush

Efficacy in % (according

Henderson -Tilton) Method of control

Before treatment

After treatment

1. Removing of infested buds 2. Removing of infested buds + 1 x endosulfan3. Removing of infested buds + 2 x endosulfan4. 3 x endosulfan 5. Check (untreated)

20.6 b* 13.8 ab 30.8 b 17.8 b 6.4 a

36.0 b* 12.8 a 9.4 a 10.1 a

20.5 ab

33.1 a* 59.2 b 86.0 c 75.8 c

– * Means followed by the same letter are not significantly different at P = 0.05, Duncan’s multiple range test Table 3. Influence of different methods of blackcurrant gall mite control (Cecidophyopsis

ribis Westw.) on occurrence of phytoseiid mites (Phytoseiidae)

Number of phytoseiid mites per 20 leaves 1998 1999 Method of control

18.V 1.VI 13.VIII 12.V 29.VI 3.VIII1.Removing of infested buds 2.Removing of infested buds + 1 x endosulfan 3.Removing of infested buds + 2 x endosulfan 4.3 x endosulfan 5.Check (untreated)

2.9 2.0 2.2 1.8 0.7

3.9 3.1 4.9 5.3 2.1

5.0 4.4 4.2 7.1 6.7

2.8 2.7 1.0 2.5 1.4

3.4 3.7 8.1 6.5 5.0

9.6 6.1 8.4 13.7 10.9

Populations of phytoseiid mites and two-spotted spider mite Generally, the number of phytoseiid mite was much higher than a number of two-spotted spider mite (Tab. 3-4). There was no significant difference in the number of predatory mites between experimental plots at all terms of the survey in both seasons. This means that endosulfan applied against the gall mite was very selective to phytoseiids. Of the collected and identified phytoseiid mites two species were dominant – Typhlodromus pyri Sch. and Amblyseius andersoni Oud. (Tab. 5). Third species, Euseius finlandicus Oud. occurred in a very low number. There weren’t any differences observed in species structure of the phytoseiid on different experimental plots. The predators were able to keep the two-spotted spider mite population on a very low level during both seasons (Tab. 4). Only in the middle of August 1998 its population grew up

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to about 4 mites per 20 leaves on the plot 3. However, it was still much below a threshold level, which is 4-5 mites per 1 leave at this time. Possibility of the successful biological control of the two-spotted spider mite with phytoseiid mite on the blackcurrant was also ascertained in other studies (Niemczyk 1996). Table 4. Influence of different methods of blackcurrant gall mite control (Cecidophyopsis

ribis Westw.) on occurrence of two-spotted spider mite (Tetranychus urticae Koch)

Number of T. urticae per 20 leaves 1998 1999 Method of control

18.V 1.VI 13.VIII 12.V 29.VI 3.VIII1.Removing of infested buds 2.Removing of infested buds + 1 x endosulfan 3.Removing of infested buds + 2 x endosulfan 4.3 x endosulfan 5.Check (untreated)

0.2 0.6 0.0 0.1 0.2

0.0 0.0 0.0 0.0 0.0

0.2 0.7

4.4 * 0.0 0.2

0.2 0.3 0.9 0.9 0.2

0.0 0.0 0.0 0.0 0.0

0.0 1.8 *

0.2 0.0 0.1

Table 5. Phytoseiid species on the plots with different methods of blackcurrant gall mite

control (Cecidophyopsis ribis Westw.)

Occurrence (% of specimens) Species 1998 1999 Typhlodromus pyri Sch. Amblyseius andersoni Oud. Euseius finlandicus Oud.

82 17 1

46 53 1

Occurrence of the aphids In 1998 aphids, especially permanent currant aphid (Aphis schneideri Born.) occurred on experimental area but the number of its colonies was different on different plots (Tab. 6). The highest number of aphid colonies was observed on the check plot and on the plot where only the infested buds were removed. On the other three plots, where endosulfan was applied once, twice or three times, population of the aphids was much lower. This means that endosulfan applied against the gall mite was also effective in the aphids control. The same was observed by Scopes and Ledien (1983). Table 6. Influence of a method of blackcurrant gall mite control on occurrence of permanent

currant aphid (Aphis schneideri Born.) in 1998

Method of control Number of aphid colonies per 1 bush

1. Removing of infested buds 2. Removing of infested buds + 1 x endosulfan 3. Removing of infested buds + 2 x endosulfan 4. 3 x endosulfan 5. Check (untreated)

3.9 b* 1.4 a 0.7 a 0.4 a 7.0 b

* For explanation see table 2.

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Conclusions Of all methods tested of blackcurrant gall mite control the highest effectiveness showed: - removal of infested buds combined with two treatments with endosulfan and, - three treatments with endosulfan. In case of a high infestation of blackcurrant crops with the gall mite removal of infested buds

only, without chemical treatment, did not give satisfactory control of the pest. Endosulfan used 1, 2 or 3 times for the control of the gall mite was highly selective to

phytoseiid mites. Due to that, phytoseiid occurred in a relatively high number and kept population of the two-spotted spider mite on a very low level during two seasons.

Only two phytoseiid species: Typhlodromus pyri and Amblyseius andersoni occurred in a relatively high number on the experimental blackcurrant plots.

At least one treatment with endosulfan should be recommended during blackcurrant flowering in order to:

- protect blackcurrants against the gall mite and, - control of other blackcurrant pests, mainly aphids. References Gajek, D. 1997. Mechanizmy odporności odmian porzeczki czarnej na wielkopąkowca

(Cecidophyopsis ribis Westw.) i biologiczne aspekty jego zwalczania. Praca doktorska. Skierniewice 1997.

Gajek, D., J. Boczek. 1998. Life-cycle of the blackcurrant gall mite (Cecidophyopsis ribis Westw.). The Biology of Gall-Inducing Arthropods. Matrafured, Hungary, August 14-19, 1997. USDA 1998, pp 131-135.

Jörg, E., J.V. Cross, eds. 2000. IOBC Guidelines for Integrated Production of Soft Fruits. IOBC/wprs Bulletin 23(5): 71 pp.

Niemczyk, E. 1996. The occurrence, species composition and effectiveness of predatory mites (Phytoseiidae) to two-spotted spider mite (Tetranychus urticae Koch) appearing on black currant plantation. IOBC/wprs Bulletin 19 (4): 374-376.

Podręcznik doświadczalnictwa polowego w ochronie roślin. IOR Poznań 1981. Program ochrony sadów i krzewów jagodowych. Skierniewice 1998. Scapre, N., M. Ledien. 1983. Pest and Diseases Control Handbook. BCPC Publication,

London.

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pp. 53 - 56

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Occurrence and effectiveness of predatory mites (Phytoseiidae) in controlling two-spotted spider mite (Tetranychus urticae Koch) on blackcurrants Edmund Niemczyk Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Poland Abstract. Poland is the largest producer of black currants in the world and two-spotted spider mite (Tetranychus urticae Koch) belongs to the most important pests of this crop. The majority of plantations in Poland have to be treated 1-3 times a year with acaricides. However, such practice creates several disadvantageous effects. Thus it seems desirable to check whether predatory mites from family Phytoseiidae could be exploited for biological control of T. urticae on blackcurrants. Key words: Phytoseidae, blackcurrant, occurrence, control Introduction The surveys on occurrence of phytoseiids on blackcurrant in Finland were conducted during 1989-1992 by Tuovinen (1995). In England Phytoseiulus persimilis (Athias-Henriot) was introduced on 40 acres of blackcurrant plantation already in 1991, where it suppressed T. urticae population (Labuschange and Wainwright, 1993). In Poland research on occurrence and effectiveness of phytoseiids in controlling spider mites on black currants was commenced in 1990 at the Research Institute of Pomology and Floriculture in Skierniewice and at Agricultural Academy in Warsaw (Kropczynska, Czajkowska, 1994 a, b; Niemczyk, 1994; Niemczyk, 1998; Niemczyk at al., 1995, 1996, 1997; Niemczyk and Sekrecka, 1998). Occurrence The surveys concerning phytoseiids on black currants were conducted in 1992 at a time of the highest occurrence of the predators i.e. from a second half of July to the end of August. At this period 121 plantations located in 11 regions of the country were examined. From each plantation 100 leaves were collected and then in a laboratory the mites present on them were counted under stereomicroscope.

The phytoseiids were observed on 48% of the plantations located in all regions. However predator's populations on majority of inhabited plantations were low or very low.

Of 121 plantations checked, more then 20 specimen of predators per 100 leaves were found only on 16. Most probably it was connected with a toxic effect to predators of some pesticides used.

Endosulfan (Thiodan) was the most often applied insecticide and mancozeb (Dithane) often used fungicide. Both were very toxic to predatory mite Neoseiulus fallacis in laboratory tests. (Niemczyk, 1997)

Eight species of phytoseiid mites were identified on the leaves collected from blackcurrant plants: Amblyseius andersoni Chant., Amblyseius bryophilus Karg, Typhlodromus pyri Scheut., Neoseiulus fallacis Garman, Euseius finlandicus Oudemans, Phytoseius macropilis Banks,

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Typhlodromus rhenanus Oudemans and Amblyseius huron Chant et Chansel (Tab. 3). A. andersoni was the dominant and A. bryophilus subdominant species. It should be underlined that E. finlandicus was observed in a high number on blackcurrants in other observations conducted in Poland (Kropczynska and Czajkowska, 1994; Niemczyk et al., 1996). The same situation occurred in Finland (Tuovinen, 1995)

The occurrence and population density of predatory mites varied in different regions. In southern part of Poland the phytoseiids were the most numerous and inhabited the highest number of plantations. On the contrary, in central and eastern parts of the country the predatory mites were noted only on a few blackcurrant plantations. Effectiveness The effectiveness of 4 phytoseiid species: Neoseiulus fallacis, Typhlodromus pyri, Phytoseiulus persimilis and Metaseiulus occidentalis was examined. Three of them (N. fallacis, T. pyri and M. occidentalis) are recognised in different geographical regions, mainly in apple orchards, as effective enemies of mites. In Poland only T. pyri occurred in a low number in some apple orchards. N. fallacis was found only in vicinity of Skierniewice on a few strawberry and black currant plantations. The remaining 2 species (P. persimilis and M. occidentalis) do not occur naturally in Poland.

The effectiveness of the above-mentioned predatory mites was investigated in 6 experiments: on two-year-old potted blackcurrant plants in field insectarium protected from the rain (2 experiments); on potted two-year-old plants in an open field (1 experiment) and on commercial plantations (3 experiments).

The influence of the following factors on predator's effectiveness was examined: predator species, variety of the blackcurrant, quantity of predators introduced and density of the prey (T. urticae) (Niemczyk, 1994).

The results of experiment conducted in the isolator with T. pyri, N. fallacis, P. persimilis and with the mixture of above-mentioned species in the situation of a high density of T. pyri (19-28 individuals per leaf) during introduction of predators showed that all examined predators effectively controlled T. urticae. However distinct reduction of the prey was noted only after 6 weeks from the introduction of predators and population of the pest dramatically fell down only after 8 weeks from phytoseid's introduction. Only P. persimilis was more active and suppressed distinctly mite's population already after 5 weeks. It should be underlined that occurrence of T. urticae on experimental plants in high quantities for long time caused heavy damage to the blackcurrant leaves.

It was found in the experiment with potted plants conducted in an open field in conditions of a good isolation between treatments (about 40 m) and with a low population density of T. urticae (about 0.5 individuals per leaf during introduction of phytoseiids) that T. pyri and N. fallacis were able to keep the pest population at a low level during the entire time experiment, i.e. longer than 10 weeks. Population density of T. urticae was the lowest (0-0.9 specimens per leaf) on control plants on which predatory mites were not released. However, these plants were inhabited naturally by native phytoseiids (Niemczyk at al., 1996).

The results obtained in a net insectarium with N. fallacis introduced on the bushes of 3 blackcurrant cultivars (Ojebyn, Titania, Ben Lomond) in a situation of a low initial population density of the pest indicated that the predator effectively limited T. urticae population on all three species of black currants. However, predator was the most effective in controlling mites on Titania cv. inhabited by T. urticae in a higher quantity (Niemczyk, 1998).

The results of an experiment conducted on commercial plantations indicated that N. fallacis

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introduced in a very high number (200 specimens per bush = about 1 specimen per leaf) controlled very effectively two-spotted spider mite. In this case only 1.2 spider mites per leaf at average were noted during the entire course of experiment. On the bushes with lower numbers of predators introduced (10, 20, 50, 100 individuals per bush) no significant differences in limiting T. urticae population by N. fallacis was observed on control plants and on plants with the predator. The average number of spider mites ranged from 3.2 to 4.2 per leaf irrespective of the treatment.

In other field experiment established on commercial plantations effectiveness of 4 different phytoseiid species (T. pyri, N. fallacis, P. persimilis, M. occidentalis and a mixture of all above mentioned specimens) in the control of two-spotted spider mite on two blackcurrant cultivars (Ojebyn and Rootknop) was checked. It was found that only T. pyri decreased the population of T. urticae on both plant cultivars. The other examined predators did not limit population of phytophagous mites both on Rootknop and Ojebyn cvs. This phenomenon could be related to the late introduction (24 June) and to a low number of predators introduced and predator's dispersion.

In the third field experiment conducted in the southern part of Poland on small plantations surrounded with a rich natural vegetation (woods, native herbaceous plants) it was found that three introduced species of phytoseiids (N. fallacis, P. persimilis and M. occidentalis) released once into blackcurrant plants, were almost entirely displaced within 2 years by 6 species of naturally occurring mite predators. Dominated: Euseius finlandicus, Typhlodromus rhenanus and Amblyseius andersoni. These native predators occurred in plantation in high numbers - especially in the second year of experiment - and kept population of T. urticae much below the threshold level (Niemczyk at al., 1996). This phenomenon indicated that on unsprayed blackcurrant plantations located in environment with rich vegetation one can expect that population of T. urticae will by very effectively controlled biologically by native species of phytoseiids inhabiting different plants grown nearby the plantation. Conclusion 1. Predatory mites (Phytoseiidae), the natural enemies of spider mites (Tetranychidae), may

occur on blackcurrant plantations. 2. According to results obtained at the Research Institute of Pomology and Floriculture eight

species of phytoseiids were found on blackcurrant plants: Amblyseius andersoni Chant, Amblyseius bryophilus Karg, Typhlodromus pyri Scheut., Neoseiulus fallacis Garman, Euseius finlandicus Oudemans and Amblyseius huron (Chant et Chansel). A. andersoni, E. finlandicus and A. bryophilus occurred in higher quantities

3. Phytoseiids appeared in low or very low quantities on majority of commercial blackcurrant plantations – most probably because of chemical treatments.

4. Native phytoseiid mites may occur in high numbers and effectively suppress two-spotted spider mite population on unsprayed blackcurrant plantations grown in environment with rich vegetation (herbaceous plants, bushes, trees)

5. Predatory mites (Neoseiulus fallacis, Typhlodromus pyri, Phytoseiulus persimilis and Metaseiulus occidentalis) introduced in adequate quantities on blackcurrants may limit population of T. urticae.

6. For economical reasons, the phytoseiids should be released on blackcurrant plantations at the time of a low population of the pest (1-2 specimens per leaf). Only in such a case it is possible to keep T. urticae below threshold level during the whole season

7. The phytoseiids introduced on blackcurrants heavily infested by T. urticae may also limit population of this pest to a low level, but it takes several weeks. During such a long time the

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phytophagous mites cause several damage to the leaves 8. The deployment of phytoseiids to control of two-spotted spider mites on blackcurrants will

be possible in practice only in a framework of IPM/IFP. In another words; it is necessary to select such pesticides or elaborate such effective, non-chemical methods of pests and disease control which would be harmless to phytoseiids.

References Kropczynska D., Czajkowska B. 1994. Próby stosowania drapieżnych roztoczy Acarina,

Phytoseiidae) do walki z przędziorkiem chmielowcem na porzeczce czarnej. In: S. Pruszyński, J. Lipa (eds.). Materialy 34 Sesjii Naukowej IOR cz.2, Postery, pp. 266-271.

Labuschange D., Wainwright H. 1993. Biological control of red spider mite in commercial blackcurrant plantations. Acta Hortic. 352: 563-568.

Niemczyk E. 1994. Występowanie, efektywność i wykorzystanie drapieżnych roztoczy (Phytoseiidae) do zwalczania przędziorka chmielowca (Tetranychus urticae ) na czarnych porzeczkach. Sprawozdanie końcowe Projektu Badawczego KBN nr 5207 9203. Res. Inst. of Pomology and Floriculture, Skierniewice.

Niemczyk E., Sekrecka M. 1998. Occurrence of predatory mites (Phytoseiidae) and their species composition on black currant plantations in different regions of Poland. Academia Techniczno-Rolnicza w Bydgoszczy, Zeszyty Naukowe - Ochrona Środowiska 214: 75-78.

Niemczyk E., 1998. Effectiveness of predatory mites (Phytoseiidae) in limiting population of two-spider mites (Tetranychus urticae Koch) on black currants. Academia Techniczno-Rolnicza w Bydgoszczy, Zeszyty Naukowe - Ochrona Środowiska 214: 65-74.

Niemczyk E., Szufa A., 1995. Preliminary experiments on effectiveness of Typhlodromus pyri Scheut. and Neoseiulus fallacis (Garman) (Phytoseiidae) to two-spotted spider mite (Tetranychus urticae Koch) on black currant. In: D. Kropczynska, J. Boczek, A. Tomczyk (eds.) The Acari. Physiological and ecological aspects of acari - host relationships, pp. 651-656, DABOR, Warszawa.

Niemczyk E., Sekrecka M., Kumor I., 1996. The occurrence, species composition and effectiveness of predatory mites (Phytoseiidae ) to two spotted spider mites (Tetranychus urticae Koch) appearing on black currant. IOBC/wprs Bulletin 19 (4): 374-375.

Niemczyk E. 1997. Toxicity of some pesticides to different populations of predatory mite: Neoseiulus fallacis (Garman) (Phytoseiidae). In: E. Niemczyk (ed.) Proc. Symp. on effectiveness and practical application of biological control in plant protection. Plant Prot. Committee, Polish Academy of Science, pp.141-148.


pp. 57 - 62

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Occurrence of phytoseiid mites (Acari: Phytoseiidae) on blackcurrant plantations and in surrounding vegetation in Southern Poland Sebastian Jaworski Warsaw Agricultural University, Department of Applied Entomology, Nowoursynowska 166, 02-787 Warszawa, Poland Abstract: The research was conducted on 10 blackcurrant plantations in the Nowy Sącz region (Southern Poland). During two vegetation seasons the samples of 100 leaves each were collected at two-week intervals from the central and border zones of the plantations. Simultaneous observations were carried out in their vicinity by taking leaf samples from the surrounding vegetation. Mites of the family Phytoseiidae found on blackcurrants belonged to 9 species: A. andersoni, A. bryophilus, E. finlandicus, T. rhenanus, Ph. echinus, T. tiliarum, T. bakeri and G. longipilus. The first four species occurred most frequently. A. andersoni was distinctly predominant – in 1998 and 1999 it constituted 63.9 and 75.5% of all collected phytoseiids, respectively. Predatory mites on the border of each plantation clearly outnumbered those found in the centre. The only exception was A. bryophilus, which prevailed in the central zone. Most phytoseiid species (except T. bakeri and G. longipilus) which occurred on blackcurrants were also found on the neighbouring plants. However, four species collected from the adjacent vegetation (Ph. soleiger, P. triporus, A. aberrans, N. reductus) did not appear on blackcurrant bushes. Our observations suggest that the spores of blackcurrant rust (Cronartium ribicola J. C. Fisher) can serve as alternative food source for predatory mites. Key words: Phytoseiidae, blackcurrant, border plants Introduction Two-spotted spider mite, T. urticae Koch is a serious pest of blackcurrants and in the integrated fruit production its control could be based on the use of natural enemies. Faunistic studies conducted in Finland by Tuovinen (1994, 1995) and in Poland by Niemczyk et al. (1997, 1998) revealed in each country as many as eight species of predatory mites inhabiting blackcurrants. Other surveys which focused on phytoseiid species associated with the vegetation adjacent to fruit crops suggested that those plants could become a reservoir of predators as a response to nonselective chemical treatments in orchards (Tuovinen & Rokx, 1991). So far, however, such observations have not referred to currant crops. Niemczyk (1998) reported that some species obtained from mass rearing and introduced into orchards were subsequently dislodged by indigenous phytoseiids over one vegetation season. A rapid response of local predatory fauna to the increase of pest population was noted also by Kropczyńska & Czajkowska (1995). The influence of plants growing in the vicinity of fruit crops on the occurrence of predatory species was subject of the research conducted during 1998 and 1999 in Southern Poland on blackcurrant plantations surrounded by opulent vegetation. The aim of the study was to determine: – mite species inhabiting both currants and surrounding vegetation, – seasonal population dynamics of phytoseiid species on blackcurrants, – influence of surrounding vegetation on the composition of phytoseiid species and their

quantity on blackcurrant plantations.

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Material and methods The study was carried out during 1998 and 1999 in Southern Poland (Nowy Sącz region) on 10 unsprayed blackcurrant plantations (0.15 – 5.0 ha) surrounded by various plant species. Every two weeks during both vegetation seasons the samples of 100 leaves each were collected separately from the central and border zones of each plantation. At the same time the neighbouring vegetation was also sampled by taking 20-100 leaves, depending on the plant species. Mite specimens found were counted and taxonomically identified. An analysis of variance (one factor) was used to assess the significance of differences for mite population density in the central and border zones of each plantation. Results Mites of the family Phytoseiidae collected from blackcurrant plantations were represented by 9 species (Tab. 1). Table.1. Occurrence of phytoseiid species on blackcurrants and surrounding vegetation

Phytoseiid species No of planta-

tion

Plant species adjacent to blackcurrent plantation Surrounding vegetation Blackcurrant

1 Triticum vulgare Vill. Urtica dioica L.

no A. andersoni, A. bryophilus

A. andersoni, A. bryophilus

2 Triticum vulgare Vill. no A. andersoni, A. bryophilus, E. finlandicus, T. rhenanus, T. bakeri

3 Aronia melanocarpa (Mich.) Prunus domestica L.

A.andersoni, Ph. macropilis, T. tiliarum A.andersoni, Ph. macropilis, T. tiliarum, T. rhenanus

A. andersoni, A. bryophilus, E. finlandicus

4 Prunus domestica L. Malus domestica Borb.

A. andersoni, E. finlandicus, T. tiliarum, T. rhenanus, P. triporus A. bryophilus, E. finlandicus, T. tiliarum

A. andersoni, A. bryophilus, E. finlandicus, T. tiliarum

5 Corylus avellana L. Aruncus silvester Kost.

A. bryophilus, A. aberrans, Ph. macropilis, E. finlandicus A. bryophilus,T. rhenanus,

A. andersoni, A. bryophilus, E. finlandicus, T. rhenanus

6 Malus domestica Borb. Corylus avellana L. Fagus silvatica L. Urtica dioica L. Mentha sp. Rubus sp.

A. bryophilus, Ph. macropilis, E. finlandicus, T. rhenanus T. rhenanus E. finlandicus A. andersoni, A. bryophilus A. bryophilus N. reductus

A.andersoni, A. bryophilus, E. finlandicus, T. rhenanus

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7 Corylus avellana L. Rubus sp.

A. aberrans, Ph. macropilis, T. rhenanus, Ph. soleiger E. finlandicus, N. reductus

A. andersoni, A. bryophilus, E. finlandicus, T. rhenanus, Ph. macropilis

8 Malus domestica Borb. Corylus avellana L. Sambucus nigra L. Prunus spinosa L.

E. finlandicus, Ph. echinus A. aberrans, Ph. echinus Ph. soleiger T. tiliarum

A. andersoni, A. bryophilus, E. finlandicus, Ph. echinus, T. rhenanus

9 Malus domestica Borb. A. andersoni, A. bryophilus, E. finlandicus, Ph. macropilis, Ph. soleiger

A. andersoni, A. bryophilus, E. finlandicus,

10 Malus domestica Borb. Prunus domestica L. Tilia platyphyllos Scop. Urtica dioica L.

A. andersoni, A. bryophilus, E. finlandicus, Ph. macropilis, T. tiliarum, A. aberrans, Ph. echinus A. andersoni, A. bryophilus, E. finlandicus, Ph. macropilis, A. aberrans E. finlandicus A. bryophilus

A. andersoni, A. bryophilus, E. finlandicus, G. longipilus

Four of them were found most frequently, i.e. A. andersoni, A. bryophilus, E. finlandicus and T. rhenanus. The first two species occurred on all inspected blackcurrant crops whereas E. finlandicus and T. rhenanus were collected from 9 and 5 plantations, respectively. The remaining species were found occasionally in very low numbers. In both years of the research A. andersoni was distinctly predominant and consecutively constituted 63.9 and 75.5% of all recorded phytoseiids. Its population averaged 54,9 specimens per 100 leaves in 1998 and 30.3 in the following season (Tab. 2). Table 2. Phytoseiid fauna on blackcurrant plantation

Percentage in phytoseiid community

Mean number per 100 leaves Species

1998 1999 1998 1999 Amblyseius andersoni (Chant) 63,9 75,5 54,9 30,3 Amblyseius bryophilus Karg 15,4 11,2 13,3 4,5 Euseius finlandicus (Qud.) 11,2 6,3 9,7 2,5 Typhlodromus rhenanus (Qud.) 7,5 5,9 6,5 2,4 Phytoseius macropilis Banks 1,4 0,2 1,3 0,06 Phytoseius echinus Wain.i Arut no 0,2 0,06 Typhlodromus tiliarum Qud. 0,1 0,01 Galendromus longipilus (Nesb.) 0,5 0,4

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The number of mites found in 1999 was less than half of that recorded the previous year, probably due to unfavourable weather conditions (intensive rainfall). The presence of major phytoseiid species, frequency of their occurrence and their proportions observed in 1999 confirmed the relevant results from the preceding season.

Total numbers of phytoseiid collected at different parts of plantations 1999.

0

50

100

150

200

250

300

A.and. A.bryoph. E.fin. T.rhenspecies

no o

f pre

dato

rs/1

00 le

aves

borderscentrumSe.

Predatory mites inhabiting the vegetation adjacent to the surveyed plantations are presented in Table 1. Of nine species collected from blackcurrants seven occurred also on the neighbouring plants. On the other hand, four species found on those plants did not appear on the

Total numbers of phytoseiids collected at different parts of plantations 1998.

0

50

100

150

200

250

300

350

A.and. E.fin. Ph.macspecies

no o

f pre

dato

rs

borderscentrumSe.

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plantations. Some herbaceous plants such as nettle and mint were inhabited by the same mite species. In both seasons the number of phytoseiids found in different zones of the plantation significantly varied for all the species. In general, specimens collected from the borders distinctly outnumbered those from the centre (Fig. 1 and Fig. 2). However, reverse results were obtained for A. bryophilus which, so far in Poland, has been reported only from blackcurrants. Now its unsubstantial populations have been found on other plants growing always in the vicinity of currant plantations. It suggests that A. bryophilus is able to disperse from currant bushes to their surroundings (Topa, 1999). The results obtained showed a strong influence of the neighbouring vegetation on the occurrence of predatory mites on blackcurrant plantations, apparently as a consequence of their migration between wild plants and crops. On most plantations the two-spotted spider mite occurred in very low numbers - its mean seasonal density did not exceed 0.33 specimen per leaf. The only exception was plantation no. 8 where in 1998 the infestation rate averaged 2.89 mites per leaf. Considering such a low density of the potential prey the question arises what could have served as a food source for phytoseiid mites? In this respect the present study points to a certain role of blackcurrant rust (Cronartium ribicola J. C. Fisher) and specifically, the spores of this fungus. On rust-infected plantations the predatory mites evidently increased in numbers. Moreover, some observations confirmed their predacious activity towards the spores of this fungal species. Conclusions – The two-spotted spider mite was kept under control by indigenous species of predatory

mites on all surveyed plantations – The family Phytoseiidae was represented on blackcurrants by nine species of predatory

mites. The predominant species was A. andersoni, which constituted over 64% of the mobile stages collected from blackcurrants during both seasons. A. bryophilus and E. finlandicus were subdominant. Other six species were found in low quantities.

– All species collected on blackcurrants inhabited the adjacent vegetation. The good host plants for phytoseiids were apple and prune trees, hazel and also nettle and mint among low growing plants. The last two species constituted a good reservoir of A. andersoni and A. bryophilus.

– A relatively higher density of predators observed in border rows of the plantation was an indication of the direct influence of surrounding plants on phytoseiid communities on blackcurrants.

References Kropczyńska D., Czajkowska B., 1995. Skuteczność drapieżnych roztoczy (Phytoseiidae) w

ograniczaniu liczebności przędziorka chmielowca na porzeczce czarnej. Materiały Ogólnopolskiej Konferencji Ochrony Roślin Sadowniczych, Skierniewice, 1-2 luty 1995, 117-119.

Niemczyk E., 1997. Występowanie i efektywność drapieżnych roztoczy (Phytoseiidae) w zwalczaniu przędziorka chmielowca na czarnych porzeczkach. Ogólnopolska Konferencja Ochrony Roślin Sadowniczych. Skierniewice, 1997.

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Niemczyk E., 1998. Występowanie i zwalczanie szkodników oraz jakość plonu w sadach z produkcją integrowaną. Ogólnopolska Konferencja Ochrony Roślin Sadowniczych. Skierniewice, 19-20 luty 1998.

Topa E. 1999. Przędziorek chmielowiec (Tetranychus urticae Koch) - szkodnik porzeczki czarnej w województwie olsztyńskim oraz rola fauny pożytecznej w ograniczaniu jego liczebności. Praca doktorska. Akademia Rolniczo-Techniczna im. M. Oczapowskiego, Olsztyn.

Tuovinen T. 1994, Phytoseiid mites on cultivated berries in Finland. In: The Acari. Physiological and ecological aspects of acari-host relationships, Dabor, 315-322.

Tuovinen T., R.J. Prokopy and W.M. Coli, 1994. Influence of surrounding trees and bushes on the phytoseiid mite fauna on apple orchard trees in Finland. Agriculture, Ecosystems and Environment 50: 39-47.

Tuovinen T. and J.A.H. Rokx, 1991. Phytoseiid mites (Acari: Phytoseiidae) on apple trees and in surrounding vegetation in southern Finland. Densities and species composition. Exp. & Appl. Acar. 12: 35-46.


pp. 63 - 65

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Eriophyoid mites of blackberries and raspberries (Rubus spp.) Aoxiang Shi Department of Applied Entomology, Warsaw Agricultural University, ul. Nowoursynowska 166, 02-787 Warsaw, Poland Abstract: Eriophyoid mites inhabiting Rubus species in Poland were investigated. Some 16 eriophyoid species belonging to 12 genera were recorded on wild and cultivated Rubus plants. Key words: eriophyid mite, Rubus Introduction There are over 3000 known eriophyoid species in the world. All of them are plant-feeding mites and most of eriophyids are quite host specific. The majority are described from single host plant and the rest are usually limited to a single genus. Eriophyid mites attack all plant parts except the roots. They can be found on almost every plant species and everywhere in the world. Our knowledge on this group of mites is very limited. Their diversity, distribution, relation to host plants, biology and dispersal are poorly known (Lindquist et al., 1996). There are two species of Rubus, which are very common in Europe and North America, e.g. Acalitus essigi and Phyllocoptes gracilis. They cause serious damage to cultivated plants in some regions (De Lillo and Duso, 1996). There have been comprehensive studies on these two known species. Other species are poorly known. Accurate identification of mite species, precise information of their biology and damage to the host plant are fundamental steps in taking control measures and understanding their potential roles in the ecosystem. Materials and methods Collection of mites Eriophyoid mites were collected with their host plants from a variety of nurseries, plantations, private gardens and natural stands of wild species in various places. Mites were removed from the plants under stereomicroscope and mounted in slides with Heinze medium. Unidentified plants were pressed in papers to dry for later define. Identification of mites Mites were observed under a light contrast microscope for identification according to the key by Boczek et al (1989). Key of Amrine (1996) was also referred. Population dynamics of Epitrimerus gibbosus Nal. Plant samples were taken at two-week intervals or monthly from blackberry and raspberry collection of the Department of Applied Entomology, SGGW in Ursynów, Warsaw. Buds, leaves, flowers and fruits were chosen randomly. Mites were counted on these plant organs under stereomicroscope. Slides were prepared to identify the mites to species. Proportions for various species for each mite species was obtained from the slide counts.

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Results About 16 eriophyoid species have been found on both blackberry and raspberry. Blackberry hosted more mite species than raspberry (Tab. 1). The most abundant species on blackberry was Epitrimerus gibbosus, followed by Acalitus orthomera, Aceria sp. and Quadracus sp., whereas on raspberry, Phyllocoptes gracilis was predominant. Table 1. Eriophyoid Mites of Blackberries and Raspberries

Mite species Blackberry Raspberry Relation to the host plants

Abacarus sp. + leaf vagrant

Acalitus essigi + berry mite

Acalitus orthomera + + bud mite

Aceria silvicola + leaf vagrant

Aceria sp.(3-rayed) + + leaf vagrant

Aceria sp.(7-rayed) + leaf vagrant

Aculodes sp. + leaf vagrant

Aculus sp. + + leaf vagrant

Anthocoptes rubi + leaf vagrant

Epitrimerus gibbosus + + leaf vagrant

Eriophyes sp. + leaf vagrant

Leipothrix sp. + leaf vagrant

Phyllocoptes gracilis + + leaf vagrant

Phyllocoptes sp. + + leaf vagrant

Quadracus sp. + leaf vagrant

Tegonotus sp. + leaf vagrant Interestingly, Acalitus essigi and Anthocoptes rubi did not survive winter of 1995/96. They were dominant species on blackberry cultivars “Thornless evergreen” and “Thornfree” before that time in Ursynow, Warsaw. Temperature of that winter was about -25°C. The possible reasons for their disappearance were: 1) they were more susceptible to low temperature, 2) host plants were killed by deep frost. Shelter for mites, e.g. buds and any other parts above ground were frozen and dried out. Mites in the buds died with the plants. New canes of the blackberry grew up from the underground roots where eriophyoid mites were not present. But how did the other species survived? That was not clear. They might be more cold resistant or they could have alternate host which withstood the low temperature and served as source of re-infestation. Fourteen eriophyoid species were associated with blackberry and raspberry in the experimental field at Ursynow, Warsaw. Epitrimerus gibbosus is the most abundant species on blackberry, while Phyllocoptes gracilis dominated on raspberry. Observation on fluctuation in Epitrimerus gibbosus population on two blackberry cultivars in 1997 to 1998

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showed that mites of this species hibernated in buds or between leaf petiole scars and auxiliary buds. The first mite moved out of the hibernation site at the beginning of April. They started to feed on leaves in May and on flowers in June. Population density on blackberry leaves reached a peak during September and October. Epitrimerus gibbosus has a complex life cycle. It has protogynes (with typical dorsal ridge) in summer and deutogynes (without dorsal ridge) only in winter. When population density was high, the mites caused discoloration on leaves. Discussion There are some 60 Rubus species in Poland. In the present study, many of the mites were collected from cultivated plants. Other samples have not been identified to their species. Accurate identification of the host plant is a critical part in describing eriophyoid mites (Amrine and Stasny, 1994). There are still works to be done before final description. Although many of the eriophyoid mites do not cause severe damages to their host plants, they may serve as an alternate food for certain kind of predators of plant pests. Conclusion A total number of 16 eriophyoid mites species belonging to 12 genera were associated with blackberry and raspberry, Rubus spp. The most often recorded species were Epitrimerus gibbosus, Phyllocoptes gracilis and Acalitus orthomera. Many of them are new records for Poland and at least 6 new species will be expected from the collection. Almost all the species are leaf vagrants except Acalitus essigi and A. orthomera. No single mite species causes obvious and economic damage to the host plants. Their potential roles in the ecosystem need to be elucidated. References Amrine, J.W., Jr. & T.A. Stasny, 1994. Catalog of the Eriophyoidea (Acarina: Prostigmata) of

the world. Indira Publishing House, West Bloomfield, Michigan, USA, 798 pp. Amrine, J.W., Jr. 1996. Key to the world genera of the Eriophyoidea (Acari: Prostigmata).

Indira Publishing House, West Bloomfield, Michigan, USA. Boczek, J.H., V.G. Shevtchenko & R. Davis, 1989. Generic key to world fauna of eriophyid

mites (Acarida: Eriophyoidea). Warsaw Agricultural University Press. 190 pp. De Lillo, E. & C. Duso, 1996. Damage and control of eriophyoid mites in crops: Currants and

Berries. In: Lindquist E.E., Sabelis M.W., Bruin J. (eds), Eriophyoid Mites: Their Biology, Natural Enemies and Control. Elsevier Sci. Publ., Amsterdam, The Netherlands, World Crop Pests, 6: 583-591.

Lindquist E.E., Sabelis M.W., Bruin J. (eds.), 1996. Eriophyoid Mites: Their Biology, Natural Enemies and Control. Elsevier Sci. Publ., Amsterdam, The Netherlands, World Crop Pests 6: 329-366.

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pp. 67 - 71

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Investigations of pheromones of soft fruit pests J. V. Cross1, P. Innocenzi1, 2 and D. R. Hall2

1Horticulture Research International, East Malling, West Malling, Kent, ME19 6BJ 2Natural Resources Institute, University of Greenwich, Chatham Maritime, Kent ME4 4TB Introduction Whilst the sex pheromones of many lepidopteran (moth) pests of soft fruit have been identified, almost without exception those of other soft fruit pests have not, even though in many cases they are known or believed to exist. However, in the last decade or so, considerable progress has been made in identifying the pheromones of non-lepidopteran insect pests of a wide range of other agricultural and horticultural crops throughout the world. Pheromones have been identified from fruit flies, gall midges, a wide range of beetles, sawflies, aphids, scale insects, plant feeding bugs (capsids), grasshoppers and locusts (reviewed by Hardie & Minks, 1999). Pheromones of a number of predators and parasites have also been identified. Many insects have a high sensitivity to pheromones which provide a powerful hook for manipulating pest behaviour in a species-specific way. Pheromones can be used to detect the presence of target insects, estimate populations and/or activity and can sometimes be exploited for control e.g. by mass-trapping, lure and kill or by mating disruption. Hence, they are invaluable tools in insect pest management. Here we report progress to date into the identification of the sex pheromones of three important pests of UK soft fruit crops, European tarnished plant bug (Lygus rugulipennnis), strawberry blossom weevil (Anthonomus rubi) and blackcurrant leaf midge (Dasineura tetensi). We speculate about possibilities for exploiting these pheromones in pest management in soft fruit crops and discuss other related research opportunities. European tarnished plant bug The European tarnished plant bug is now known to be an important pest of late season strawberries. Damage is caused by nymphs or adults feeding in the flowers and on young developing fruits. The flesh surrounding achenes on which the pest has fed do not develop normally whereas undamaged ones swell and ripen. This leads to the development of distorted ”cat-face” “or nubbined”’ fruit which start to appear about 3 weeks after the onset of bug feeding. MAFF-funded research at HRI-East Malling and HRI-Efford has shown that the pest can cause damage at very low population densities of less than 1 bug/20 plants. Populations of the pest can be assessed by beating or suction sampling, but these methods are difficult and time consuming and are not likely to be used widely by growers. The existence of a sex pheromone was known because traps baited with live females attracted conspecific males, and work to identify the sex pheromone of the European tarnished plant bug started at HRI-East Malling and NRI, Chatham in 1998. Volatiles emitted by males and females were collected and analysed and three physiologically-active volatile components produced by females but absent from males were identified by mass spectrometry. The compounds identified are hexyl butyrate, (E)-2-hexenyl butyrate and (E)-4-oxo-2-hexenal in 39:1:3 ratio (Innocenzi et al.,

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1998). The first two compounds can be synthesised readily at low cost, but synthesis of the third compound is more time-consuming and costly. In 1998, preliminary field tests of blends of the three synthetic pheromone components were conducted in an abandoned 2-year old everbearer strawberry crop at HRI-East Malling. White sticky traps baited with two- and three-component blends caught more males and less females than the unbaited control traps, although the numbers of individuals caught were small and differences were not statistically significant. However, in 1999, white sticky traps baited with the blend of all three components did not catch significantly more or less bugs than unbaited white traps in a purpose-sown field of flowering herbs (Matricaria recutita, Chenopodium album and Senecio vulgaris) infested heavily with the bug. The reasons for this result are not clear. Possible explanations are that the trapping was started too late, that the pheromone release rates were incorrect or that the visual attractiveness of the white traps was overriding as the white flowers of the Matricaria recutita senesced. Similar difficulties are being encountered by other researchers with the characterisation of the sex pheromones of related species, Lygus lineolaris in North America and Lygocoris pabulinus in The Netherlands, for which similar components have been identified (reviewed by McBrien & Millar, 1999). Thus, further work is needed to characterise and test the pheromone of the European tarnished plant bug. In the laboratory, electrophysiological studies are currently being repeated to ensure a further vital component has not been overlooked, and in the field further field testing of pheromone blends is needed. Current evidence suggests that this pheromone may be difficult to exploit for control but, if an effective lure and trap can be developed, it will be very useful for monitoring the pest. Strawberry blossom weevil The strawberry blossom weevil, Anthonomus rubi, is a common pest of strawberry throughout Europe. Damage to strawberry is caused by the female which, after inserting an egg into an unopened flower bud, walks a few millimetres down the flower stem and punctures it with her rostrum, partially severing it and causing it to wither. A single female may sever numerous flowers. MAFF-funded research at HRI-East Malling and HRI-Efford has shown that, where excessive numbers of flowers are present on the June-bearer Elsanta, this damage does not adversely affect yield or quality and can be beneficial. Where the number of flowers is small in relation to the yield potential of the plant, so that an average of 15g of yield or more is needed per flower to reach full yield potential, the plant is unable to compensate for severing by maturing replacement flowers or increasing berry weight; yield is then reduced in proportion to the proportion of flowers severed. On everbearers, severing delays cropping. Strawberry blossom weevil is currently controlled by sprays of the organophosphorous insecticide chlorpyrifos applied against adults in spring at the start of flower stem extension before significant damage is done. Sprays are applied almost as a routine. In March 1999, several sacks of leaf litter were collected from the bottom of a Leylandii hedge at Parkwood Farm, Boughton Monchelsea, Maidstone, Kent. The hedge was adjacent to a field that had previously had a strawberry crop heavily infested with blossom weevil in 1998, but which had been grubbed the following winter. Five blossom weevil adults, four males and one female, were found by sifting through the leaf litter in the laboratory. These were drowsy from winter hibernation but becoming active. They were transferred individually to plastic boxes and supplied with strawberry flowers on which they settled and started to feed. A few days later, they were transferred individually on fresh strawberry flowers to apparatus for collecting volatile chemicals. The volatile compounds collected from the males

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and the female were compared using gas chromatography – mass spectrometry analysis and six compounds present in the male collections but absent from the female collections were identified. Four of these compounds, known as Grandlure components I-IV, were the same as the pheromone components of the related cotton boll weevil, Anthonomus grandis, although in different relative proportions. The other two compounds were lavandulol (one optical isomer only) and germacrene-D. The four Grandlure components and a racemic mixture of the two lavandulol optical isomers are available from chemical suppliers. Lures were produced using polyethylene sachets as slow-release dispensers for a range of different blends of the five available components, and these were tested in three commercial strawberry fields in 1999. Traps were white, sticky sheets (20 x 20 cm) held horizontally about 20 cm above the plant on a wooden stake with the lure positioned centrally on the sticky surface. Five different combinations of Grandlure 1-4 components and the lavandulol racemate were tested in a 5x3 (treatment x replicate) randomised block experiment design. Blends of Grandlure I/II + lavandulol or Grandlure I-IV + lavandulol were found to be significantly more attractive than Grandlure I/II, Grandlure I-IV or lavandulol. The latter treatments did not differ significantly from the unbaited control. We have recently discovered an easy and rapid method for sexing the weevils, based on the presence of large coxal thorns on the intermediary legs of males but absent on females, and this has enabled the trap catches to be sexed revealing that males and females are attracted. The work to date has shown that volatiles emitted by male blossom weevils attract males and females. Thus this pheromone is a sex/aggregation pheromone. The fact that the pheromone attracts females (as well as males) makes it more likely that it will be possible to exploit the pheromone for not only monitoring but also for control by mass-trapping or lure and kill approaches. Further work to optimise the pheromone blend, including testing the germacrene-D and individual lavandulol optical isomers, and to optimise the lure and trap design is the first priority. The optimised lure and trap needs testing in the field to determine the relationship between populations and trap catches and the range of attractiveness. Ultimately, mass-trapping and lure and kill approaches need to be investigated in large-scale field trials. Blackcurrant leaf midge Until recently, the blackcurrant leaf midge was a widespread and damaging pest of commercial blackcurrant plantations in the UK. Larvae feed in the leaves in shoots causing characteristic distortion. Severe damage stunts shoot growth, and the pest is particularly troublesome on the re-growth of cut-down bushes. The pest has declined in importance in recent years due to the widespread use of routine sprays of fenpropathrin (Meothrin) for control of blackcurrant gall mite. However, the pest is likely to resurge in importance as the gall mite-resistant and reversion virus-resistant cultivars Ben Hope and Ben Gairn become planted more widely and are grown without routine acaricide applications. Garthwaite et al. (1986) showed that there was evidence for a powerful female-produced sex pheromone in blackcurrant leaf midge. Traps baited with newly emerged virgin females caught large numbers of males in the field whereas traps containing virgin males were unattractive to males or females. The pheromone of the blackcurrant leaf midge has not been identified. At that time, no gall midge pheromone had been identified but, since then, there has been considerable progress with the identification of the sex pheromones of two gall midge species. The first was that of the Hessian fly in New Zealand (Foster et al.,1991) and, recently, the sex pheromone of the pea midge has been identified (Hillbur et al., 1999).

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Research funded by MAFF and HDC/SmithKline Beecham to identify the sex pheromone of blackcurrant leaf midge started at HRI-East Malling and NRI, Chatham in April 1999. Mature larvae were collected from the field and reared individually to adult. Volatiles were collected from virgin males and females separately in a similar way to that described for the strawberry blossom weevil above, but not in the presence of the host plant. Ovipositors were excised from females and collected in organic solvent. Chemical and electrophysiological analysis of the samples is in progress. Conclusions Identification of the sex pheromones of these three soft fruit pest species should lead to better means of pest monitoring to determine whether and when to apply control measures. Depending on the nature of the chemical compounds involved, their activity, stability and cost of synthesis, it may well prove possible to exploit them for control. This will then provide means of reducing the dependence of soft fruit growers on pesticides. Not all insects produce or utilise pheromones. For instance there is no evidence for a sex pheromone of the vine weevil, Otiorhynchus sulcatus (a species for which only females are known to exist and which reproduces parthenogenetically). Work is in progress at the Institute of Arable Crops Research, Rothamsted and in the Netherlands to investigate vine weevil aggregation pheromones and plant volatiles (Van Tol & Visser, 1998). The role of other semiochemicals, including plant volatiles, in the ecology of soft fruit pests has been little investigated. Pheromones of several other important non-lepidopteran pests of soft fruit crops probably exist and are worthy of investigation. In some cases, this task might prove relatively quick and straightforward. In others, identification may prove difficult and protracted. It cannot be predicted at the outset how easy the task will be or how useful any pheromone might be for monitoring and control. However, significant opportunities are apparent. Acknowledgements This work is funded by MAFF, the Natural Resources Institute, University of Greenwich, SmithKline Beecham and the HDC and Blackcurrant Grower’s R&D fund. We are very grateful to the fruit growers who have supported our work, notably John Worley, Harry Wooldridge and Graham Cuthbert and also to Richard Harnden and James Wickham for their enthusiasm and encouragement. References Foster, S. P., Harris, M. O. & Millar, J. G. 1991. Identification of the sex pheromone of the

Hessian fly, Mayetiola destructor (Say.) Naturwissenschaften 78: 130-131. Garthwaite, D. G., Wall, C. & Wardlow, L. R. 1986. Further evidence for a female sex

pheromone in the blackcurrant leaf midge Dasineura tetensi. Proceedings of the British Crop Protection Conference – Pests and Diseases 1986, 1: 355-357.

Hardie, J. & Minks, A. K.(Eds.) 1999. Pheromones of Non-Lepidopteran Insects Associated with Agricultural Plants. CABI Publishing.

Hillbur, Y., Anderson, P., Arn, H., Bengtsson, M. Löfqvist, J., Biddle, A.J., Smitt, O., Högberg, Plass, E., Franke, S. & Francke, W. 1999. Identification of sex pheromone components of the pea midge, Contarinia pisi (Diptera: Cecidomyiidae). Naturwissenschaften 86: 292-294.

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Innocenzi, P., Hall, D. R., Sumathi, C., Cross, J. V. & Jacobson R. 1998. Studies on the sex pheromone of the European tarnished plant bug, Lygus rugulipennis (Heteroptera: Miridae). Proceedings of the Brighton Crop Protection Conference, 3: 829-832.

McBrien, H. L. & Millar, J. G. 1999. Phytophagous bugs. In: Pheromones of Non-Lepidopteran Insects associated with Agricultural Plants (Eds. J. Hardie & A. K. Minks). CABI Publishing, pp. 277-304.

Van Tol, R. W. H. M. & Visser, J. H. 1998. Host-plant preferences and antennal responses of the black vine weevil (Otiorhynchus sulcatus) to plant volatiles. Proceedings of Experimental and Applied Entomology, N.E.V. Amsterdam, 9: 35-40.

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Aims and objectives of Reduced Application of Chemicals in European Raspberry Production (RACER) project Stuart C. Gordon, J. A. Trefor Woodford Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, United Kingdom Abstract: The aims and objectives of a 2-year EU-CRAFT project to reduce pesticide application on European red raspberry (Rubus idaeus) are described. Commercial and scientific partners from six countries in Europe have joined to develop suitable monitoring and/or forecasting methods to detect and control a range of arthropod pests and to develop a standardised monitoring system for fungi causing post-harvest rots. Wherever possible, existing monitoring systems have been examined and modified for the local environment. Sticky white traps (Rebell® bianco) have been used to develop a spray threshold for raspberry beetle (Byturus tomentosus). The efficiency of the traps has been improved by use of natural plant odours. Two-spotted spider mites (Tetranychus urticae) are widespread, but can be controlled by use of naturally occurring or artificially introduced predatory mites. The raspberry cane midge (Resseliella theobaldi) emergence model, developed in the UK, is being tested in different locations in Europe. As yet, further evaluations will be required to ensure the level of reliability required. At least five species of Otiorhynchus have been found on raspberry in Europe. The populations can be assessed by trapping or beating. A standardised post-harvest rot assessment has been developed for use throughout Europe to detect a range of fruit-infecting fungi. Training workshops are an important part of this initiative to transfer the technology to growers and extension workers. Key words: IPM, monitoring, forecasting, raspberry, raspberry beetle, two-spotted spider mite, raspberry cane midge, weevils, post-harvest rots, fungi Introduction Raspberry (Rubus idaeus) is a valuable small fruit crop grown in various parts of the world. Raspberry and other Rubus berries (blackberry and other hybrids) are high value perennial crops with a long establishment period incurring high capital costs. To protect this investment and assure high quality fruit production, most growers currently rely on the use of fungicides and insecticides, often spraying prophylactically to prevent fruit damage and loss of yield (Gordon, et al. 1997). Raspberries and other cane fruits are grown in a wide range of geographical locations. In Europe, for example, locations vary from flat coastal plains and valleys to moderately steep upland areas which would be unsuitable for most arable crops. These diverse growing conditions offer opportunities for continuity of supply of fresh fruit within Europe. Consumers and their suppliers are now demanding production systems that use the minimal amount of artificial pesticides and fertilisers to produce fruit of high quality, harvested free from blemishes, rots and moulds. It was this that led some European raspberry producers to join together to form a consortium with four science centres to bid for funding to initiate a pan-European approach to Integrated Crop Management.

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RACER Partnership The RACER partnership comprise a group of Small to Medium Sized Enterprise (SME’s) all with an interest in either producing and/or marketing cane fruit in various European countries. (See table 1). Table 1. Partnership and role within the RACER project Partner (Partner No.) Country Role Type of enterprise

Scottish Soft Fruit Growers Ltd (A1)

Great Britain

Core Partner (Prime Proposer)

Grower owned co-operative marketing and processing mainly frozen fruit

Associazione Produttori Agricoli Sant’Orsola s.c.ar.l. (A2)

Italy Core Partner Marketing and packaging mainly fresh fruit for growers co-operative

Dr. D. Perlepes (A3) Greece Core Partner Representing a consortium of farmers establishing a new raspberry industry

Valmira Frutas LDA (A4)

Portugal Core Partner Fruit and vegetable production company establishing raspberries in Portugal

Pakkasmarja Oy (A5) Finland Core Partner A company established by small fruit farmers to market and process fruit

Stiftung Behindertenbetriebe in Kanton Schwyz (B1)

Switzer-land

Non-Core Partner Provider of protected-environment employment for handicapped adults and manufacture of insect traps

Scottish Crop Research Institute (C1)

Great Britain

Prime RTD Performer (Project Coordinator)

A research and lead centre in Europe for research in cane fruit crops

Istituto Agrario Provinciale di S. Michele all’Adige (C2)

Italy RTD Performer A research and teaching organisation with experience in fruit research in North Italy

Agricultural Research Centre (MTT) Institute of Plant Protection (C3)

Finland RTD Performer A research centre with experience in integrated pest management on top and small fruits

Eidgenössische Forschungsanstalt für Obst-, Wein- und Gartenbau (FAW) (C4)

Switzer-land

RTD Performer FAW is a research and development centre involved in integrated production of environmentally acceptable and economically viable fruit production.

National Agromet Unit, ADAS (C1)

Great Britain

Sub-contractor to SCRI

Research and development centre with expertise in agro-meteorological modelling and forecasting

Biomathematics & Statistics Scotland (C1)

Great Britain

Sub-contractor to SCRI

UK leaders and have international reputation in applied and biological sciences mathematics and statistics

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Figure 1. Map showing location of RACER SME partners and RTD Providers (letters and

numbers in boxes refer to RACER Partners - see Table 1.) Funding of RACER project This 2-year project, largely supported by Small to Medium Sized Enterprises (SMEs) is funded by the European Commission (FAIR FA-S2-CT97-9038) and Bundesamt für Bildung und Wissenschaft (BBW) in Switzerland. Aims of RACER project Good yields come from best practice in crop production within the variables of climatic factors to which Rubus are distinctly vulnerable. Avoiding damage as far as possible from pest infestation and disease attack is vital to the economics of Rubus fruit production. Growers must balance the need to produce high quality fruit against the increasing pressures from retailers and consumers to reduce chemical inputs (and hence residues). In countries where raspberries are an established crop, production guidelines rely heavily on chemical applications to control pests and diseases. European Rubus (raspberry and blackberry) crops have a number of pests and diseases either affecting fruit quality or fruit yield. Some are extremely damaging if not controlled by timely application of pesticides. Currently, there are approximately eight fungal diseases and eight arthropod pests which cause moderate to severe damage to raspberry. Most are controlled by routine application of pesticides, often as ‘insurance’ spray programmes. In some production areas, as many as 12 applications of pesticides are required in the pre-fruiting stage in any one season from leaf burst to green fruit stage, a period of 3 to 4 months. The Consortium recognised the urgent need to reduce the number of applications and to find suitable environmentally benign replacement products which can be integrated into modern production systems, e.g. Integrated Pest Management (IPM).

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The Consortium identified the following insect, mite and fungal disorders of raspberry that cause economic loss and require urgent research (Table 2.). They are raspberry beetle (Byturus tomentosus), two-spotted spider mite (Tetranychus urticae), raspberry cane midge (Resseliella theobaldi), the Otiorhynchid weevils (Otiorhynchus spp.) and post-harvest fungal diseases (e.g. grey mould (Botrytis cinerea) and other fruit rotting fungi). Table 2. Target cane fruit pests and diseases – economic importance and current control

Pests and diseases Economic importance

Treatments per annum

Class of product

Raspberry beetle * * * * * 2 OP/P/C/other Two-spotted spider mite * * * * 2 - 4 OC/other Raspberry cane midge * * * * 2 OP Otiorhynchid weevils * * * * 2 OP Post-harvest rots (moulds) * * * * * 7 F

***** major importance, widespread; **** very important, causing crop damage in most years; *** locally important; ** rarely causing severe damage; * minor importance throughout the Europe. Product abbreviations: OP = Organophosphorus, P = Synthetic Pyrethroid, C = Carbamate, OC = Organochlorine, F = Fungicide. The main objectives of RACER Project are described in Table 3. In addition to the main tasks, additional objectives include the transfer of technology developed in one country to another, dissemination of the results obtained throughout the producing industry and undertake training for both extension workers, field specialists and local growers through a series of training workshops given by visiting specialists. Support will be given to the SMEs in southern Europe who are diversifying from traditional crops into high value raspberry production. The final objective is to prepare a series of ‘advisory leaflets’ on the various topics addressed by the project that may then provide the foundation for a new Code of Best Practice for Rubus production in Europe. Table 3. List of main objectives of the project

Task Main objective 1 Monitor adult raspberry beetle flight activity with view to developing spray

threshold and improve trap efficiency 2 Develop methods to manage and understand two-spotted spider mite population

development in raspberry 3 Improve raspberry cane midge population forecasting by transfer of existing

technology 4 Develop monitoring system to predict Otiorhynchid weevil activity in raspberry

plantations 5 Develop standardised procedure to identify and assess levels of post-harvest rot

fungi in European raspberry plantations and evaluate current low-input fungicide treatments

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Preliminary results and discussion Having a multi-centred IPM research on raspberry has proved to be a great success by bringing together a critical mass of research workers in different geographical and climatic growing conditions. This spread of expertise has also permitted research on a wide range of arthropods and fungi that may not have been possible at a single centre. The involvement of the SMEs in targeting the main pest species has given the project a specific focus that is essential to meet the needs of industry. On the negative side, since the research is being done under the auspices of the EU-CRAFT programme, there is only 24-months of funding for the research which is a severe limitation with long-term perennial crops like raspberry. As the Intellectual Property (IP) for this research remains with the SMEs, some aspects must remain confidential. The results given below are in out-line only. Raspberry Beetle Results from trials in the first year showed that a spray threshold for raspberry beetle based on catches on white sticky traps (Rebell® bianco) developed in Switzerland (Höhn, 1991) is possible, but the threshold may have to differ depending on the country and final end-market. Olfactometer and electroantennogram (EAG) experiments have shown that raspberry beetles are attracted to natural plant odours (Birch et al., 1996). Wind tunnel experiments, done as part of this project, have identified chemicals that are attractive to the beetles, and one that is repellent. Testing these compounds in the field during flowering in 1998 gave inconclusive results, but when evaluated in 1999, using an improved delivery system, one compound proved to be very attractive to beetles in the period from adult emergence to flowering. Two-spotted Spider Mite The size of the two-spotted spider mite populations has been quite variable. Numbers were low in both of the most southerly sites, in Portugal and in Greece. A predatory mite (Phytoseius plumifer) collected in Greece by J A T Woodford during an expert visit in May 1999, and identified by T. Tuovinen, is thought to keep two-spotted spider mite numbers low on raspberries in Greece. The influence of naturally-occurring and artificially-reared predatory mites on two-spotted spider mite populations are being studied in Italy, Finland and Switzerland. Raspberry Cane Midge Emergence of first generation raspberry cane midge is determined by the detection of first eggs in artificial wounds made in the bark of primocanes in the spring. An emergence model has been used successfully in the UK since the early 1990s (Gordon et al., 1989). Trials have been done in Italy, Finland, Switzerland and the UK in an attempt to utilise it elsewhere in Europe. The model works very well in the UK, with first oviposition occurring within 4 days of the predicted date, but further evaluations are required elsewhere to develop the same level of precision. Otiorhynchid weevils This study has shown that there are at least five species of Otiorhynchus associated with red raspberry in Europe. Monitoring traps were assessed at different locations. In the UK, nocturnal beating was more effective than traps, whereas in Finland and in Italy diurnal beating is more efficient.

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Post-harvest Rots A post-harvest rot test based on a 80 fruit sample has been developed and successfully used in most participating countries. As expected, Botrytis cinerea (grey mould) was the most frequently isolated fungi. Other fungi isolated from the fruit included Rhyzophus stolonifer, Alternaria spp., Cladosporium cladosporioides, Penicillium spp. and Aspergillus spp. Training and Technology Transfer Contact with growers and extension workers is essential if IPM is to be accepted. The RACER project has a major aim to ensure that the project is fully understood by growers and a series of training workshops have been held. Table 4. Details of training workshops and meeting where the aims of the RACER project and

details of the pests and diseases were given to growers and extension workers.

Location Date Approx. Number Attending

Oeschberg, Switzerland 29 January 1998 * Pergine Valsugana, Italy 25 February 1998 120 Suonenjoki, Finland 2 April 1998 150 Blairgowrie, Scotland mid May 1998 30 Zambujeira do Mar, Portugal 26 May 1998 8 Lamia, Greece 29 May 1998 6 Pieksämäki, Finland 9 June 1998 * Oeschberg, Switzerland 5 February 1999 * Suonenjoki, Finland 15 February 1999 20 Jyväskylä, Finland 7 March 1999 *

(* number not recorded) Dissemination of information to other fruit growers is important and popular articles have appeared in local farming journals in Finland (Kasvinsuojelulehti and Puutarha & kauppa), Italy (Vita Trentina and Supplemento all'Informatore Agrario), Switzerland (Schweizerische Zeitschrift für und Obst-Weinbau) and in the UK (Grower). The project is also on the World Wide Web at http://www.scri.sari.ac.uk/racer/default.htm and is up-dated periodically. Acknowledgements We thank the many growers who have and are participating in this project. We also thank the staff in the participating SMEs for their time and input and all the research staff at the various Research Establishments for their hard work and dedication. Ms Joan Duffin, formerly of SCRI, is thanked for her invaluable assistance in developing the early stages of the project. We also thank the EU and Bundesamt für Bildung und Wissenschaft (BBW) for funding the project.

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References Birch, A.N.E., Gordon, S.C., Griffiths, D.W., Harrison, R.E., McNicol, R.J., Robertson,

G.W., Spencer, B., Wishart, J. & Woodford, J.A.T., 1996. The role of flower volatiles in host attraction and recognition by the raspberry beetle, Byturus tomentosus. IOBC/wprs Bulletin 19(5): 117-122.

Gordon, S.C., Barrie, I. A. & Woodford, J.A.T., 1989. Predicting spring oviposition by raspberry cane midge from accumulated derived soil temperatures. Annals of Applied Biology 114: 419-427.

Gordon, S.C., Woodford, J.A.T. & Birch, A.N.E., 1997. Arthropod pests of Rubus in Europe: pest status, current and future control strategies. Journal of Horticultural Science 72: 831-862.

Höhn, H., 1991. Farbtafeln zur Schädlingsüberwachung im Beerenanbau. Schweizerische Zeitschrift für Obst- und Weinbau 127: 249-252.

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Minimised fungicide application using tunnel sprayer in strawberries – biological effects and practical experiences Holger Daugaard, Peter Kryger Jensen and Bent Løschenkohl Danish Institute of Agricultural Sciences, Department of Fruit, Vegetable and Food Science, DK-5792 Aarslev, Denmark; Danish Institute of Agricultural Sciences, Department of Crop Protection, DK-4200 Flakkebjerg, Denmark; Danish Institute of Agricultural Sciences, Department of Plant Biology, DK-4200 Flakkebjerg, Denmark Abstract: Two different sprayers were tested in strawberries with regard to their biological effects on Botrytis cinerea Pers. The sprayers were an unshielded row application kit and a tunnel sprayer, both with 4 nozzles per row. The result of the comparison showed that their biological effects were comparable. It is concluded that using the tunnel sprayer may make it possible to reduce the dose of tolylfluanide, compared to a row application kit. Key words: Strawberry, Botrytis cinerea Pers., fungicide application, tunnel sprayer Introduction During the last few years, the Danish environmental authorities have critically reviewed all pesticides used in Danish agriculture and horticulture. As a result of this procedure, a considerable number of pesticides have now been banned. For other pesticides, limitations have been introduced, or exemptions have been given for a limited number of years. As fruit and berry growing is of minor importance in Denmark, the chemical companies are not very interested in getting expensive approvals for new pesticides. Especially for fruit crops requiring frequent spaying, the situation is therefore very serious. One obvious example is strawberries, in which only 1 fungicide was approved in the beginning of 1998. Due to this situation a new research project was initiated, sponsored by the environmental authorities. The project was initiated in 1997 and will be finished in year 2000. One aim of this project was to investigate the possibilities of non-chemical alternatives in the control of grey mould (Botrytis cinerea Pers.). Another aim was to look into the spraying technique, trying to find alternative equipment causing a minimised loss of pesticides to the environment. Non-chemical alternatives included are defoliation after harvest, defoliation and removal of plant material after harvest and finger harrowing. This is based on common practical experiences. The use of finger weeders is claimed to affect the occurrence of Botrytis. Besides, the effect of plant distance and fertilisation practice is also included. Most of the treatments mentioned above are known to have effects on the occurrence of Botrytis and are more or less included in all IFP guidelines, but in this project we are trying to assess the combined effect of all treatments. As far as spraying technique is concerned a Swedish tunnel sprayer (JT-Bandspruta) has been selected to be tested, in order to reduce dosages and loss of fungicides to the environment. In this publication preliminary results of this test is presented.

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Materials and methods A+ frigo plants of two cultivars (‘Elsanta’ and ‘Korona’) were planted on flat beds in the field in May 1997. Each plot consisted of 6 rows with 15 plants in each row. The plant spacing in the row was 0.37 m and the row spacing used was 0.9 m. There were 4 replications. All flowers were removed six weeks after planting. During the season, all plots were fertilised according to soil and leaf analyses and irrigated in dry periods. Weeds, pests and diseases were controlled according to normal practice in 1997. In July 1998 and 1999, yield and berry size was recorded in all plots, but only for 12 plants situated in the 2 central rows of each plot. Berries were also picked from the rest of the plants, which were considered guard plants. The weight of marketable berries, Botrytis-attacked berries and other not marketable berries was recorded separately. Berries less than 22 mm or misshapen were considered not marketable. The plants were protected during the winter period by covering with agryl (synthetic mulch). In 1998 and 1999, the experiment included a comparison of the use of different application techniques when controlling Botrytis. Two different sprayers were used, an unshielded row application kit with 4 nozzles per row and JT tunnel sprayer with a 60 cm shield and also with 4 nozzles. For both sprayers, the nozzle type used was Hardi S4110-16. During flowering, 3-5 applications were made with 3 kg per hectare of dichlofluanide in 600 litres per hectare. When using the tunnel sprayer, the amount of fungicide sprayed per hectare was reduced to 2 kg per hectare. All data were subject to statistical analysis using the General Model of SAS (SAS Institute, Inc., 1989-95, Cary, NC). The least significant differences between means were determined at P < 0.05 using Duncan’s test. Results and discussion In tables 1 and 2 results are presented for 1998 and 1999, respectively. In none of the years significant differences between treatments could be recorded. Especially in 1998 – the first fruiting year – the two varieties yielded differently. The yield of ‘Korona’ this year was nearly twice the yield of ‘Elsanta’ but in 1999 the difference was eliminated. Table 1. The biological effects of unshielded and tunnel sprayers in 1998

Botrytis cinerea Variety/ Treatment

Total yield T per hectare

Marketable yield T per hectare T per hectare % of berries

Both varieties Unshielded 21.2a 19.0a 0.3a 1.4 Tunnel 21.4a 18.8a 0.3a 1.4 Unsprayed 21.0a 18.4a 0.5b 2.4 Korona Unshielded 27.3a 24.4a 0.5a 1.8 Tunnel 27.4a 24.0a 0.5a 1.8 Unsprayed 27.3a 23.5a 0.8b 2.9 Elsanta Unshielded 15.0a 13.6a 0.2a 1.3 Tunnel 15.4a 13.6a 0.1a 0.6 Unsprayed 14.7a 13.3a 0.2a 1.4

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The Botrytis attack on berries was generally very moderate in 1998, whereas it greatly increased in 1999. Such differences between years are not uncommon and may often be explained by climatic differences during flowering. In 1999 the climate was relatively mild and humid whereas it was cooler in 1998. Also, Botrytis attacks normally tend to increase with plant age (Daugaard, 1999). When the two sprayers are considered, it was demonstrated in this trial that their biological effects on the control of Botrytis were comparable. This result is obtained despite the fact that the dose with the shielded JT tunnel sprayer was 2 kg ha-1 and the unshielded row application kit used 3 kg ha-1. The different doses were chosen in order to compare the potential in the shielded technique, and the result cannot be used as a general conclusion that the dose can be reduced with 33% when the shielded JT tunnel sprayer is used as an alternative to an unshielded row application kit. The result indicates however that the shielded tunnel sprayer might possess a potential for reducing the fungicide dose, which needs to be further exploited. On the other hand, the use of JT tunnel sprayer did not further improve the control of Botrytis, a fact which may be expected as the type and number of nozzles and pressure used were constant. Table 2. The biological effects of unshielded and tunnel sprayers in 1999

Botrytis cinerea Variety/ Treatment

Total yield T per hectare

Marketable yieldT per hectare T per hectare % of berries

Both varieties Unshielded 37.1a 28.4a 7.6a 20.5 Tunnel 38.3a 28.6a 8.1a 21.1 Unsprayed 33.6b 24.3b 8.1a 24.1 Korona Unshielded 38.4a 27.4a 10.3a 26.8 Tunnel 40.0a 27.0a 12.0a 30.0 Unsprayed 35.7a 23.4b 11.6a 32.5 Elsanta Unshielded 35.7a 29.5a 4.8a 13.4 Tunnel 36.7a 30.3a 4.4a 12.0 Unsprayed 31.5b 25.2b 4.9a 15.6

In a previous study the JT tunnel sprayer gave better coverage in the canopy of strawberries compared to a traditional boom sprayer which gave good coverage only in the upper part of the canopy (Nordmark et al., 1993). Furthermore, by using the JT tunnel sprayer the loss of pesticides to the environment is reduced compared to an unshielded row application kit (Jensen & Spliid, 1998). References Daugaard, H. 1997. Gråskimmel i jordbær – fremtidens bekæmpelse. Frugt og Bær 26: 174-

175. Daugaard, H. 1998. Nytt dansk gråskimmelprosjekt. Norsk Frukt og Bær 1 (1): 9.

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Daugaard, H. 1999. Cultural methods for managing grey mould (Botrytis cinerea Pers.) of strawberry. Biological Agriculture and Horticulture 16: 351-361.

Jensen, P.K. and Spliid, N.H. 1998. Afdrift fra sprøjteudstyr til svampebekæmpelse i jordbær. Effekt af afskærmet jordbærbom og ledsageluft til almindelig marksprøjte. DJF-Rapport nr. 3: 229-238.

Nordmark, L., B. Mattsson and S.-A. Svensson 1993. Förbättrad appliceringsteknik – minskad användning av bekämpningsmedel inom grönsaks- och bärodling. SLU Info/Trädgård rapport 376, pp. 60.


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Spray application techniques in Integrated Production of soft fruit Grzegorz Doruchowski, Barbara Łabanowska, Artur Godyń, Ryszard Hołownicki Research Institute of Pomology and Floriculture, Pomologiczna 18, PL 96-100 Skierniewice, Poland Abstract: Among the requirements of the integrated production of soft fruit there are none regarding the spraying technique whereas it is recognised to be a crucial factor influencing both the biological effect of treatments and a risk of environmental pollution. The specialist sprayers designed to the type of crop should replace the conventional equipment that cannot ensure effective and safe use of chemicals. The calibration of the sprayers allowing proper selection of the sprayer’s working parameters as well as an official inspection of the sprayers guaranteeing their safe and correct operation also contribute to efficient and safe use of chemicals. The requirements concerning the type of the sprayers, calibration and inspection of spray equipment should be discussed and implemented in the general IFP rules Key words: soft fruit, integrated production, spraying technique, sprayer calibration, sprayer testing Introduction A chemical plant protection in integrated fruit production should cause minimum possible damage to the environment. The spraying technique that is used to apply plant protection products in soft fruit is a crucial factor influencing both the biological effect of treatments and risk of environmental pollution. It has especially great meaning in Poland, which is one of the leading producers of soft fruit and where the chemicals are used at a large scale to protect fruit crops against agrophagi. The sprayers and the way the treatments are made are not the only important things to be taken into account in IFP. The calibration of the sprayers allowing for proper selection of the sprayers’ working parameters as well as an official inspection of the sprayers guaranteeing their safe and correct operation considerably contribute to efficient and safe use of chemicals. Among the requirements of the integrated production of soft fruit there are many regarding chemicals but none are connected to the spraying technique. Having recognised it’s importance we suggest to implement the requirements concerning the type of sprayer as well as calibration and inspection of sprayers in the general IFP rules. In this paper some arguments are presented to support this suggestion and to be a germ of a discussion.. Sprayers The environment-friendly spraying techniques should assure satisfactory biological effect with a minimal dose of a chemical applied only where needed and with minimum emission to the environment. This can be achieved with the sprayers performing a precise, target-oriented spray application. Thus, the design of the sprayer dedicated to soft fruit depends on the size and type of a crop.

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Strawberries In the strawberry plantations the conventional field crop sprayers are still commonly used. Since they apply the spray uniformly along the boom, the same amount of chemicals is deposited on the plants and on the soil between the rows of plants. This soil deposition is an obvious economical loss and a considerable source of soil contamination, which is in contradiction with the code of a good practice in plant protection and especially with the rules of IFP. These conventional field crop sprayers should be replaced by the target-oriented row-crop sprayers (Fig. 1) in which the spray is directed on the plants to use chemicals more efficiently and to minimise the deposition on the soil. In the row-crop sprayer each row of strawberries is sprayed by the 3 or 4 plant oriented nozzles mounted on the frame or adjustable arms. These frames are attached on the horizontal boom and spaced according to the row spacing so several rows of strawberries can be sprayed during one pass. With the row-crop sprayers a satisfactory biological effect is achieved at spray volumes 600 l/ha, compared to 1200-2000 l/ha used with conventional sprayers (Bera et al., 1983). In our own studies we found that even lower volume (400 l/ha) was very efficient in control of grey mould (Botrytis cinerea) and two-spotted spider mite (Tetranychus urticae) (Doruchowski, 1999). To minimise the spray drift and wind interference in the spray deposition process the mini-tunnels are used instead of frames. According to Daugaard (1999), a satisfactory control of grey mould can be obtained with a tunnel sprayer with a fungicide dose reduced to 2/3 of that recommended for applications done by conventional sprayers. The best results are obtained with the air-assisted row-crop sprayer (Fig. 2). This machine has the nozzles mounted in the centre of round spouts from which air-jet is emitted to take the drops at a high speed to the target surface and simultaneously ruffle its leaves. Usually two spouts are directed at different angles at each row of plants. The air assistance ensures a good penetration and cover of the spray over the plant even during windy conditions. The operational advantages of the sprayer include the ability to reduce spray volumes to 1/10 of the traditional one and use higher driving velocities (Taylor & Druin, 1987). Antonin et al. (1989) obtained better grey mould control with spray volume 200 l/ha applied with air assistance than 200 and 800 l/ha without air. The volumes 200-400 l/ha are practically used by Polish strawberry growers using air-assisted row crop sprayers to control pests and diseases. Thus, the row crop sprayers are not only environmentally friendly but they also give a profit to the strawberry grower.

Figure 1. Row-crop sprayers for strawberries Figure 2. Air-assisted row-crop sprayer

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Bush fruit The bush fruit such as currants, goose berries, raspberries and choke berries need air assistance for spray application. The conventional orchard sprayers with a radial air emission system are commonly used in bush fruit plantations. Since these machines were designed to spray over the trees, the range of spray emission is not well matched to the bushes, which results in poor canopy penetration and high spray loss. To reduce the range of spray plume generated by the conventional mistblowers the air deflectors can be mounted on the axial fans (Fig. 3) or the special directed air-jet systems can be used (Fig. 4). By directing the air-jet to the bushes the spray is applied more precisely with lower emission to the environment. According to Cross and Walklate (Lovelidge, 1993) one can obtain better canopy penetration with the sprayer producing several air jets coming from different angles then when the air flow comes from one direction. The researchers compared the effect of treatments in black currants made with a pneumatic sprayer where the droplets were carried by numerous air currents with a conventional radial flow mistblower. The pneumatic sprayer produced 20% higher deposit and 50% higher coverage on currant leaves than did the conventional sprayer. Due to a better penetration the pneumatic sprayer ensured more uniform spray distribution within the bush canopy, which resulted in a more efficient control of American gooseberry mildew (Sphaerotheca mors-uvae) and leaf midge (Dasyneura tetensi). Doruchowski et al (1999) evaluated the canopy penetration and spray loss produced by the directed air jet sprayer with ten (five per side) adjustable air spouts at the end of flexible ducts and conventional radial flow mistblower. The results showed that in the directed air jet sprayer the spray deposit was considerably higher and the spray loss to the air several times lower than in a conventional sprayer. Thus, once again the more precise application technique performed by the specialistic sprayers gave better treatment quality with lower environmental pollution. These sprayers should replace the conventional mistblowers and their use should be required in integrated production of bush fruit.

Figure 3. Deflector sprayer for bush fruit Figure 4. Directed air-jet sprayer for bush fruit

Calibration of sprayers The calibration of the sprayer means determining the basic working parameters of the machine in order to accomplish the spray job according to the requirements. These requirements may specify the spray volume, spray quality (nozzles) or field capacity.

While the introduction of the new spraying technique needs an investment the calibration of the sprayer can be done by the owner without any costs. Setting the correct working parameters

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being a result of the calibration ensures applying a precise dose of a chemical with minimum chemical residue in the tank. The optimal selection of travel velocity, nozzles and pressure results in reduced spray emission to the environment. During the calibration all the functions of the sprayer are checked, the damaged and worn out parts are replaced and all the necessary repairs are done. This eliminates or at least reduces to minimum the risk of a break-down of the sprayer during the treatments. The accuracy of spray application and reliability of the calibrated sprayer lead always to the increased efficacy and reduced costs of plant protection with minimum emission to the environment. Inspection of sprayers Deposition of insufficient dose of chemicals fails to kill the agrophagi and in long term it can lead to development of a resistance to the product. On the other hand, too high dose of applied chemical can lead to intolerable concentration of residue, which may remain for a long time in the fruit. The herbicides applied in the wrong place can easily destroy nearby plants. In every case the expensive protective agents and time are wasted at the expense of both the grower and the environment. It is therefore vitally important that the spraying equipment should be perfectly maintained, in a good operational condition and reliable. For this reason in many countries the voluntary or compulsory regular inspections of sprayers has been introduced. The inspections are carried out by the approved test stations equipped with a professional diagnostic equipment which guarantees a high quality service. During the inspection the sprayer is checked for functionality, reliability and application accuracy as well as for a safety for the operator and the environment. The whole testing procedure is usually made in the presence of the sprayer’s owner and the evaluation is done in form of discussion with him. This educational character of the inspection results in increased grower‘s knowledge and awareness on plant protection technology. In some countries in the test stations the sprayers are also repaired and/or upgraded if the sprayer’s owner wishes so. With the professionally tested and adjusted sprayer the grower can be sure that the carefully prepared chemical is applied where it is needed and in the proper quantity. All his efforts and expenses are not in vain when the spraying equipment itself works correctly and reliably. Only in such a case the spraying method meets the requirements of a safe, economical and efficient use of plant protection products. Conclusions 1. The use of modern spraying techniques dedicated to the crops, careful and systematic

calibration of the sprayers as well as inspection of sprayers made by professional testing stations give the growers a better biological effect of plant protection at the lowest chemical input, minimised spray loss and reduced costs of treatments.

2. The requirements regarding the type of sprayer dedicated to the crop, calibration and inspection of spray equipment should be implemented in IFP rules.

References Antonin, Ph., Mittaz, Ch., Fellay, D. & Udry, V., 1989. Techniques d’applications

phytosanitaires en cultures de fraisiers (Spraying techniques in strawberries). Revue Suisse

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Vitic. Arboric Hortic. 21(4): 247-250. Bera, B., Cichocki, J., Czuba, S. & Mrozowska, T., 1983. Porównanie skuteczności różnych

technik opryskiwania plantacji truskawek przeciwko szarej pleśni. Prace Instytutu Sadownictwa i Kwiaciarstwa, Seria A, 24: 347-354.

Daugaard, H., 1999. Personal communication. Danish Inst. of Agricultural Sciences, Dept of Fruit and Vegetables, kirstinebjergvej 10, DK-5792 Arslev, Denmark, tel: +45 63904343, fax: +45 63904396, e-mail: [email protected]

Doruchowski, G., 1999. Technika ochrony truskawek. Ogólnopolska Konferencja Truskawkowa, ISK Skierniewice 9.03.1999: 37-48.

Doruchowski, G., Łabanowska, B., Goszczyński, W., Godyń, A. & Holownicki, R., 1999. Spray deposit, spray loss and biological efficacy of chemicals applied with different spraying techniques in black currants. International Conference on Techniques in Plant Protection, Warsaw 23.-26.05.1999, SGGW-AR Warszawa, pp: 25-32.

Lovelidge, B., 1993. Spraying all directions. Grower 120(13): 20-21. Taylor, W. & Druin, B., 1987. Spray deposit on strawberries when applied with air assistance at

differing volume rates. Proceedings Crop Protection in Northern Britain 1987: 324-329.

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Improving strawberry spraying J. V. Cross, A. M. Berrie and R. A. Murray Horticulture Research International, East Malling, West Malling, Kent ME19 6BJ, UK Abstract: The effect of two spray volumes (160 l ha-1 ‘LV’ and 530-540 l ha-1 ‘MV’) and two spray qualities (‘fine’ VMD=181-187 µm and ‘medium’ ‘VMD’=221-232 µm) on the efficacy of myclobutanil and bupirimate for mildew control, of dichlofluanid and iprodione for Botrytis control and of the clofentezine for two-spotted spider mite control on strawberries (cvs. Tango and Bolero) was compared factorially. The strawberries were grown on raised, polythene-mulched beds and sprays were applied with a Hardi Mini Variant air-assisted sprayer with three ducts directed at each bed.

Medium volume spray treatments were consistently more effective for mildew control than the LV treatments and the fine spray quality treatments tended to be more effective than the medium spray quality treatments at the same spray volume. Efficacy of mildew control on leaves was in the order: MV fine>MV medium>LV fine>LV medium. Botrytis levels were too low to identify possible differences between treatments. Clofentezine reduced two-spotted spider mite by c 90%, but there were no significant differences between spray treatments. Tracer tests showed the percentage of the under-surfaces of leaves covered with spray deposits was 71%, 66%, 36% and 28% for the MV fine, MV medium, LV fine and LV medium treatments respectively. The relative efficacy of the treatments for powdery mildew control was attributed to these differences in spray cover. Key words: mildew, Botrytis, two-spotted spider mite, fungicide, acaricide, spray application, air-assistance Introduction A survey of strawberry spraying practice in 1995 (Cross & Berrie, 1995) revealed a very wide range of strawberry spraying practices in the UK. Spray volumes varied between 150-1300 l/ha; four different basic designs of sprayer were used commonly, spray qualities varied from very fine to medium; the numbers of nozzles targeting each row or bed varied from 1.3 to 8, forward speeds varied from 4 to 8.1 km h-1. It was concluded that the very wide range of spraying practices was due to a lack of clear information on the most effective methods for spraying strawberries. A literature review (Cross & Berrie, 1995) revealed that the amount of published research on strawberry spraying is very limited, most investigations concentrating on the measurement of bulk spray deposits and the control of Botrytis on fruit. The work indicates that gross spray retention increases and that Botrytis control is not significantly reduced at lower volumes. To provide a better understanding of the requirements for effective spraying, an experiment funded by the UK Horticultural Development Council was done at HRI-East Malling in 1998. The objective was to determine the effects of spray volume and spray quality on the efficacy of control of powdery mildew, Botrytis and two-spotted spider mite, and on spray deposits and their distribution. The results of the experiment are reported here. Materials and methods A plantation of strawberries consisting of a 5 x 5 Latin square of 25 plots was established. Each plot comprised four 6m long, 1m wide, parallel, adjacent, raised, polythene-mulched

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beds spaced 2 m apart of strawberry plants. Each bed had 25 plants in a double (zig-zag) row with 0.4m spacing between plants and between rows. Plots were separated by 1.0m at their ends and by 2.0 m at the sides. Two ever-bearer strawberry varieties, cvs. Tango and Bolero, were planted in each plot, in a split-plot design.

Treatments were four different methods of spray application comprising a factorial comparison of two spray volumes (530-540 and 160 l ha-1), two spray qualities (medium (VMD = 221-232 µm) and fine (VMD = 181-187 µm)), and an untreated control (Table 1). Table 1. Treatments

Treatment Nozzle colour∗

Pressure (bar)

Flow rate (l min-1)

Volume rate (l ha-1)

VMD (µm)

Medium volume - fine green 14.0 3.03 541 18 Medium volume – medium blue 6.8 2.98 530 23 Low volume – fine orange 4.6 0.895 160 187 Low volume – medium red 1.9 0.890 160 22 Untreated control – – – – –

∗ Albuz ATR series (black ringed tip)

The different volumes and drop sizes were generated by selected Albuz (ATR series) ceramic, hollow-cone hydraulic nozzles operated at pressures chosen to give the required flow rates and drop size spectra. The drop size spectra were measured at Silsoe Research Institute using a Dantec phase doppler analyser. All sprays were applied with a Hardi Mini Variant air assisted sprayer. Three of the sprayer’s air ducts, each furnished with a single nozzle in the centre of its orifice, were trained to target each bed. One of the ducts was targeted at the centre of the bed from vertically above and was angled 30° forward. The other two ducts targeted the sides of the bed and were angled 30° backwards. One bed was sprayed at a time. The forward speed of the sprayer was 5.0 km h-1 and the power-take-off (PTO) rotational speed of the tractor was 430 rpm.

A programme of sprays, principally of the fungicides myclobutanil (Systhane) (90 g a.i. ha-1) for powdery mildew control and dichlofluanid (Elvaron) (2.25 kg a.i. ha-1) for Botrytis control, was applied according to each treatment on 22 June, 3, 13, 28 July, 25August, 2, 11, 23 September and 12 October 1998. Dichlofluanid was not applied on 22 June or 2 September because flowers were not present. To control two-spotted spider mite populations that had in-creased steadily during August, a spray of the acaricide clofentezine (Apollo)(200 g a.i. ha-1) was applied according to each treatment on 2 September 1998. Pest and disease assessments The percentage of the under-surfaces of young, fully expanded leaves affected by powdery mildew was assessed in the field viz. 23-24 July, 21 August and 16 October 1998. On each occasion, one fully-expanded, trifoliate leaf from each of the 12 plants in the centre of each bed of each plot (=24 per plot) was removed from the plant and the percentage of the leaf area affected by powdery mildew was estimated using a standard assessment key (Anon., 1976). In addition, a random sample of 50, 1-2 cm diameter green fruitlets of each variety, was collected from each plot on 26 August 1998. The numbers affected by powdery mildew were determined in the laboratory by examination for the presence of the disease. For two-spotted spider mite, a random sample of 25 fully expanded leaves of each variety was taken from the

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central plants in each plot on 16 September 1998, 14 days after acaricide treatment, and the numbers of mites estimated using the leaf brushing technique (Henderson & McBurnie, 1942). Motile stages and eggs were counted separately. Data were subjected to analysis of variance after appropriate transformation. Quantitative tracer tests To determine the volumes of spray deposited on the plants by each spraying method, a spray tracer test was done on 23 September 1998. One row of five plots was sprayed sequentially by each spraying method in turn using a different EDTA chelated metal salt as a spray tracer (1g metal l-1 + 0.1% v/v non-ionic wetter (Minax)) for each spraying method viz. MV medium- manganese, MV fine – zinc, LV medium – copper, LV fine – cobalt. The spray deposit from one treatment was allowed to dry completely before the next was applied. The air temperature and relative humidity just before and after treatment applications were 19.8 °C and 64% at 14.10 h and 17.4°C and 77% at 17.10 h respectively. The wind speed averaged 2 ms-1 (gusting to 3 ms-1) and was in a direction at right angles to the beds. After each spray application, the spray solution was discarded and replaced by a solution of the same tracer at the same concentration containing the dye tartrazine (10 g l-1). A small separate plot of approximately 20 plants was sprayed with this solution. Previous experiments have shown that tartrazine can be recovered quantitatively from leaves by aqueous extraction and so was used as an internal standard for estimating the recovery factor for the primary tracers.

Immediately after the deposit from the last spray application had dried, the following samples were taken from the plots that had received the four superimposed spray treatments: 1. 40 replicate composite random samples of 25 leaflets, comprising 10 samples from the

periphery and 10 from the inside of the canopy of the plants of each of the two varieties. 2. 40 replicate composite random samples of 25 flowers, comprising 10 samples from outside

the leaf canopy and 10 from inside the canopy of the plants of each of the two varieties. 3. 200 individual flowers, 100 selected at random from each variety. 4. 200 individual leaflets, 100 selected at random from each variety.

The samples were stored overnight in aluminium mesh baskets (to prevent sweating and so minimise absorption of the tracer deposits into the leaf) in the laboratory. The following day, each sample was weighed and transferred to a polythene bag. Water was added to each bag, which then was shaken vigorously for 10-15 s to extract the tracer. The volume of water used for extraction was 50 ml for composite samples of leaflets, 10 ml for composite samples of flowers sampled from outside the leaf canopy, 20 ml for composite samples of flowers sampled from inside the leaf canopy, and 5 ml for individual leaflets and flowers. The concentrations of the metal salts were measured by atomic absorption spectroscopy, using analytical standards derived from each of the field-collected samples of spray tank solutions (ascribed a nominal concentration of 1 gl-1). The concentration of tatrazine was determined by measurement of optical absorbence at 436nm using a UV-visible spectrophotometer. The areas of leaf samples were estimated from their area:weight ratio of 44.3 cm2g-1. The volume of spray deposited by each spray treatment per cm2 of leaf or per flower per 100 l of spray applied per hectare was then calculated. Data were subjected to analysis of variance.

The mean area of leaf surface per plant was estimated by destructively sampling all the leaves of each of five plants of each variety and measuring the total area of leaf surface of each plant. The mean leaf area index for each variety was then calculated, from which the proportion of applied spray retained on the leaves of the plant could be estimated.

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Spray cover On 4 November 1998, a spray of the fluorescent, water-soluble tracer Tinopal CBS-X (2% w/v) in admixture with the non-ionic wetter Minax (0.1% w/v) was applied to the variety Bolero, using each of the four sprayer configurations. A separate plot was sprayed by each spraying method. Immediately after the spray had dried, a random sample of 100 fully expanded leaflets was taken from the periphery of the leaf canopy, and a further 100 from inside the leaf canopy. The underside of each leaflet was illuminated by UV light (366nm) in a dark chamber, and a digital image of the fluorescent deposit was captured by a video camera linked to a Macintosh computer. The image was analysed using image analysis software (NIH-Image, US National Institutes of Health available in the public domain on the Internet at http://rsb.info.nih.gov/nih-image/) to provide estimates of the percentage of the under-surface of each leaf covered with spray. Table 2. Mean % (and angular transformed %) of lower leaf surface infected with mildew on

23 July, 21 August and 16 October 1998 and mean % of green fruitlets (1-2 cm diameter) infected with mildew on 26 August 1998.

Treatment Mean % leaf area infected Angular transformed % leaf

area infected Tango Bolero Mean Tango Bolero Mean

Leaves assessed 23 July 1998 (SED=2.29*) MV fine 0.09 0.18 0.14 0.39 0.66 0.53 MV medium 0.08 0.32 0.20 0.40 1.43 0.92 LV fine 0.93 2.95 1.94 2.47 5.12 3.79 LV medium 5.4 1.15 3.28 6.98 3.43 5.21 Untreated 40.6 40.5 40.6 38.5 38.7 38.6

Leaves assessed 21 August 1998 (SED=2.74*) MV fine 8.2 19.2 13.7 11.9 20.6 16.2 MV medium 10.8 29.2 20.0 13.7 29.1 21.4 LV fine 16.5 42.0 29.2 19.2 38.8 29.0 LV medium 29.0 60.2 44.6 28.3 53.5 40.9 Untreated 80.9 82.5 81.7 69.0 70.6 69.8

Leaves assessed 16 October 1998 (SED=1.75*) MV fine 3.6 2.1 2.8 6.1 3.9 5.0 MV medium 6.1 4.8 5.4 7.6 6.7 7.1 LV fine 5.2 8.1 6.7 8.2 12.4 10.3 LV medium 5.9 9.8 7.9 8.2 13.0 10.6 Untreated 24.2 26.8 25.5 26.0 26.6 26.3

Green fruitlets assessed 26 August 1998 (SED=4.84*) MV fine 23.1 8.7 15.9 27.3 15.5 21.4 MV medium 25.4 8.1 16.7 29.3 14.7 22.0 LV fine 36.0 15.3 25.7 35.7 22.2 29.0 LV medium 19.9 11.7 15.8 24.3 18.5 21.4 Untreated 51.2 34.2 42.7 45.3 35.5 40.4

* SEDs are for comparisons between mean angular transformed values only

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Results Powdery mildew All the spray treatments reduced levels of infection significantly compared to the untreated control on the three assessment dates (Table 2). However, the MV fine treatment had consistently the smallest amounts of mildew and the LV medium treatment the greatest. The MV treatments were consistently more effective than the LV treatments and the fine spray quality treatments tended to be more effective than the medium spray quality treatments at the same spray volume, though differences were only large enough to be statistically significant on 21 August. Thus the efficacy of the treatments for mildew control on leaves fell into a clearly defined order: MV fine>MV medium>LV fine>LV medium. There were no significant differences between the mean percentage leaf areas infected on the two varieties.

All the spray treatments reduced the percentage of green fruitlets 1-2 cm in diameter infected with mildew significantly compared to the untreated control. However, there were no statistically significant differences between the spray treatments. Botrytis The percentages of ripe fruits infected with Botrytis were very low, usually near zero, even on the untreated control plots. The highest percentages were recorded on 6 August 1998 when approximately 4% of fruits on the untreated control plots were infected. Percentages were smaller for the fungicide-sprayed treatments, but the data were too erratic and contained too many zero values for valid statistical analysis. Two-spotted spider mite By 16 September 1998, all the spray treatments with clofentezine (Apollo) applied on 2 September had reduced the numbers of two-spotted spider mite eggs and motile stages significantly by a factor of 10 fold or more compared to the untreated control (Table 3). However, there were no significant differences between the spray treatments themselves. Table 3. Mean numbers of two-spotted spider mite Treatment Tango Bolero Mean

Eggs Motiles All Eggs Motiles All Eggs Motiles All Mean numbers of mites MV fine 831 115 946 96 31 127 464 73 537 MV med. 210 65 274 163 25 188 186 45 231 LV fine 383 95 479 312 101 412 348 98 445 LV med. 617 131 747 278 65 343 447 98 545 Untreated 5149 1549 6698 3270 1470 4740 4210 1510 5719 Spray deposits Significantly greater spray deposits were recovered from the composite samples of 25 leaves (50% greater) and from the composite samples of 25 flowers (25% greater) for the MV medium and LV fine treatments than for the MV fine and LV medium treatments (Table 4). On cv. Tango, deposits on outer leaves were approximately double those on leaves sampled from the inside of the plant but, on cv. Bolero, volumes deposited on inner and outer leaves

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were similar. The leaf area indices for cv. Tango and cv. Bolero were 1.03 and 1.30 respectively indicating that grand means of 13.8% and 28.1% respectively of the applied spray were deposited on the crop. Casual observation suggested that he rest was lost mainly as deposits on the ground (mostly on the polythene) with a small percentage as spray drift.

Table 4. Mean volumes of spray deposited on composite samples of 25 leaves (including

upper and lower leaf surfaces) (µl cm-2 per 100l ha-1 sprayed).

Tango Bolero Treatment Inside Outside Mean Inside Outside Mean

Mean volumes deposited on leaves (SED = 0.022) MV fine 0.09 0.16 0.13 0.17 0.14 0.16 MV medium 0.12 0.28 0.20 0.22 0.24 0.23 LV fine 0.13 0.31 0.22 0.27 0.29 0.28 LV medium 0.12 0.15 0.13 0.27 0.13 0.20

Mean volumes deposited on the undersides of leaves by the different spray treatments had the same pattern of relative values as those on the composite samples of leaves: the MV medium and the LV fine treatments had significantly greater values than the MV fine or the LV medium (Table 5). However deposits on cv. Tango were consistently greater than on cv. Bolero. The four different spray treatments gave broadly similar leaf-to-leaf distributions of deposits on the under-surfaces of leaves. Statistical analysis showed that the log-normal distribution provided a good fit to the data for each variety. Coefficients of variation were calculated. These showed that the LV medium treatment (CV = 127%) gave markedly more variable deposits than the other three treatments (CV= 85-90%).

As for the individual leaves, statistical analysis showed that the log-normal distribution provided a good fit to the data for each variety. Coefficients of variation were calculated. The LV treatments tended to have higher coefficients of variation (85% for the data for both varieties combined) than the MV treatments (70-74%), though differences were small and inconsistent The four different spray treatments gave similar flower-to-flower distributions of deposits. at the individual variety and sampling zone level.

Table 5. Mean volumes (µl cm-2 per 100l ha-1 sprayed) of spray deposited on the under-surfaces of individual leaves and coefficients of variation

Tango Bolero Treatment

mean CV% Mean CV% MV fine 0.15 86 0.10 70 MV medium 0.27 87 0.17 78 LV fine 0.24 88 0.18 88 LV medium 0.17 128 0.12 116

Spray cover There were large, statistically significant differences in the percentage of the under-surfaces of leaves covered with spray deposits of the fluorescent tracer Tinopal CBS-X (Table 6). In

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descending order of magnitude, the overall mean % cover was greatest for the MV fine treatment (71%) followed by the MV medium treatment (66%) followed by the LV fine treatment (36%) with the smallest % cover on the LV medium treatment (28%). The MV treatments gave significantly better cover on the undersides of outer leaves than inner, but it was vice versa for the LV treatments. Table 6. Percentage of under-surfaces of leaves covered with spray estimated by image

analysis of deposits of the fluorescent tracer Tinopal CBS-X

Treatment Inner Outer Mean

Mean % leaf under-surface covered with spray (SED = 2.13)

MV fine 61.1 80.0 70.5 MV medium 57.1 75.4 66.3 LV fine 42.7 29.7 36.2 LV medium 30.9 25.1 28.0 Mean 48.0 52.6 50.3

Discussion The results show clear, consistent differences in the efficacy of control of powdery mildew on leaves. The MV fine treatment was most effective, followed by the MV medium treatment followed by the LV fine treatment with the LV medium treatment being least effective. The 3.4 fold increase in spray volume between the LV (160 lha-1) and MV (540 lha-1) treatments gave a greater increase in efficacy than the 1.4 fold reduction in Volume Median Diameter (VMD) from the medium (221-232 µm) to the fine (181-186 µm) spray quality. Higher volume sprays of finer quality are likely to be more efficacious than lower volume, medium quality sprays for mildew control. However, differences are likely to be small, perhaps insignificant, if sprays are applied more frequently (e.g. weekly) and/or if infection pressure is lower. The degree of efficacy of mildew control appeared to be related to the percentage spray cover on the undersides of leaves. Efficacy increased with increasing spray cover. Myclobutanil (Systhane) is a partially systemic fungicide. However, a higher percentage cover ensures that a greater proportion of the leaf surface is protected by high levels of surface deposit. It is possible that uptake of fungicide into the plant is greater and more efficient when it is spread over a greater area of leaf surface. Levels of Botrytis were too low to discriminate between the efficacy of treatments. Fairly good control (c. 90%) of two-spotted spider mite was achieved by all the treatments. This result is perhaps surprising, as clofentezine (Apollo) is a contact-acting ovicide. A greater proportion of eggs would be contacted directly by spray from treatments that gave a higher percentage spray cover on the undersides of leaves, where the mites occur.

The significantly greater deposits with the MV medium and LV fine treatments are difficult to explain. The differences occurred on leaves and flowers of both varieties in both sampling zones, on upper and lower leaf surfaces combined and on the lower surfaces alone. It is suspected this result is an artifact of the tracer methodology used. Possible explanations are that the recoveries of the individual tracers were not accurately estimated or that successive spray treatments interfered with each other.

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The log-normal distributions of leaf-to-leaf and flower-to-flower deposits indicate that significant proportions of leaves or flowers are likely to have a very much greater deposits on them than the means. The LV medium treatment gave a markedly more variable deposit than the other treatments indicating that this treatment should be avoided.

Acknowledgements This work was funded by the Horticultural Development Council, UK. We are very grateful to John Handford, FAST for his advice and support with the conduct of this work. We are also grateful to Claire Bultler-Ellis, Paul Miller and Peter Walklate, Silsoe Research Institute who made the drop spectra measurements. References Anon. 1976. Agricultural Development and Advisory Service Strawberry Mildew Assessment

Key 8.1.1. MAFF, 2 pp. Cross J. V. & Berrie A. M. 1995. Strawberry: A review of the published literature and

available information on spray application for pest and disease control on commercial crops. Report to HDC on contract No. SF 42 issued 1 December 1995, 36 pp.

Henderson C. F. & McBurnie H. V. 1942. Sampling techniques to determine populations of the citrus red mite and its predators. US Department of Agriculture, Circular 671: 1-11.


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Weed species on soft fruit plantations in Poland Jerzy Lisek Research Institute of Pomology and Floriculture, Department of Fruit Crop Management and Plant Nutrition, Pomologiczna 18, 96-100 Skierniewice, Poland Abstract: Weeds community has been described in 1993-1999 on strawberry, currants, raspberry, gooseberry and blueberry plantations located in Central, Eastern and Southern Poland. Annual and perennial weed species with frequent occurrence on soft fruit plantations have been mentioned. The connections among the kind of weeds on plantations and environmental factors, method of weed control and the age of plantations have been found. Key words: weed species, soft fruits Introduction Weeds on small fruit plantations not only compete for nutrients and water but also have negative allelopathic effect on growth and yield of cultural plants. They reduce harvest efficiency, increase fungal diseases and are host for virus and phytoplasma factor insects. For this reason weeds control is recommended. The efficient weed control is difficult as weeds belong to different botanical families and have different biology. The essential condition of choice of an efficient control method is the knowledge of weed species, which are a problem on plantations. Species richness of weed communities is determined by natural components (soil, climate) and artificial ones (kind of crop, method of control) and it is still evolving. Long-term field studies on the distribution of weed species and modelling its relation to the environment are useful to define an emergency of weed species infestation (Dessaint 1999, Mikulka & Chodová 1999). Only part of all Polish flora species can be a problem as weeds in different crops (Tymrakiewicz 1976, Szafer et al. 1988). Weed societies on strawberry and fruit bush plantations are specific in comparison with other crops (Lisek 1997, 1999). Material and methods Species richness of weed communities was determined on 56 plantations of strawberry, currants, raspberry, gooseberry and blueberry. The investigations were carried out in 1993-1996, in three regions of Poland (main town or village in the brackets): – Central (Skierniewice, Łowicz); – Eastern (Kraśnik, Opole Lubelskie); – Southern (Nowy Sącz, Brzezna). The assessment was done three times a year during April/May, July/August and September/Oktober. The localities differed in soil and climate conditions, forecrops, cultural practices (prior to planting and during weed evaluation) and age of plantations. Differences in methods of weed control were especially important. The most popular method of plantation management for currants, raspberry and gooseberry was mechanical soil cultivation with rotavator in the interrows and herbicide application in the zone of bushes. Numerous mowing of weeds in interrows on older plantations was typical in Central Poland. For plantations

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localised in Southern Poland with high quantities of precipitation and in eastern part located on loam soils, low growing perennial grasses were the basic method of weed control in alleyways. On most of the strawberry plantations mechanical soil cultivation was combined with herbicide use. The soil on some of the strawberry plantations was mulched with plastic or straw. Blueberry plantations were mulched with peat or tree bark and herbicides were used as an additional method of weed control. During the assessments the presence of weed species on plantations and their frequency (percent of soil area covered with one species in comparison with the whole weed community) were evaluated. Results and discussion The plantations were infested with annual and perennial weed species (Tab. 1 and 2). The species were divided into three groups: I – dominant - species from this group were present on more than 80% of all the plantations.

The frequency on the plantations infested with this species was high; often more than 20% of soil was covered with weeds during the time of one assessment.

II – important - species were found on 30-80% of the evaluated plantations. The frequency differed from 5% to more than 20% of the all number of weeds, but generally was lower than for species from I group.

III – specific for some plantations – occurs on less than 30% all the plantations. The typical frequency for this group on infested plantations was below 10% of soil covered with weeds but on few plantations (respectively some parts of the fields) was high.

Table 1. Annual weed species on soft fruit plantations Group of frequency

Weed species

I – dominant

Stellaria media, Senecio vulgaris, Lamium purpureum, Chenopodium album, Capsella bursa-pastoris, Viola arvensis, Amaranthus retroflexus, Poa annua, Echinochloa crus-galli

II – important

Conyza canadensis, Geranium pusillum, Anthemis arvensis, Anthemis cotula, Matricaria maritima subsp. inodora, Chamomilla recutita, Chamomilla suaveolens, Polygonum persicaria, Polygonum aviculare, Fallopia convolvulus, Galium aparine, Urtica urens, Setaria viridis, Setaria glauca, Veronica persica, Veronica hederifolia, Bromus hordeaceus, Lamium amplexicaule, Raphanus raphanistrum

III – specific

48 species, the most popular of them: Erodium cicutarium, Digitaria sanguinalis, Gnaphalium uliginosum, Lactuca serriola, Atriplex patula, Galinsoga parviflora,

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Table 2. Perennial weed species on soft fruit plantations. Group of frequency

Weed species

I – dominant

Taraxacum offcinale, Agropyron repens, Equisetum arvense, Cirsium arvense, Convolvulus arvensis

II – important

Artemisia vulgaris, Rumex acetosella, Rumex crispus, Rumex obtusifolius, Achillea millefolium, Rorippa sylvestris, Sonchus arvensis, Vicia cracca, Malva neglecta, Trifolium repens

III – specific

39 species, the most popular of them: Urtica dioica, Polygonum amphibium var. terrestre, Ranunculus repens, Epilobium adenocaulon, Epilobium montanum, Potentilla reptans, Potentilla anserina, Mentha arvensis, Stachys palustris, Solidago canadensis, Plantago maior, seedlings of Tilia, Acer, Betula and other tree species

Only a few annual and perennial weed species were found on almost all plantations. The greater number of species was connected with specific environmental conditions. For example, Erodium cicutarium and Digitaria sanguinalis were found on dry soils, Gnaphalium uliginosum, Mentha arvensis, Polygonum amphibium var. terrestre were typical for wet localities, Polygonum aviculare, Chamomilla recutita, Plantago maior were found first of all on the places near highways, but P. aviculare expanded progressively to the whole area of plantations. The weed species spectrum on strawberry plantations was similar to those from arable lands in the same conditions. Annual weed species were dominant in strawberries due to corn as a forecrop, soil tillage and short time of plantation exploitation (3-4 years). The number of perennial weeds increased with the age of plantations, especially on those strawberry fields where herbicides were used as the main way of weed control. Soil mulching with plastic did not fully protect against weed emergency. Seeds of Poa annua and Echinochloa crus-galli often emerged in the places where strawberries were planted. Straw mulching sometimes caused infestation of weeds typical of corn, e.g. Centaurea cyanus. Perennials species were more frequent on the bush plantations than on strawberry. The number of perennials increased with the age of plantation as a result of many years of soil tillage absence in the bush rows or on the whole plantation. Some of annual weed species (Thlaspi arvense, Galinsoga parviflora) were typical of newly planted bush plantations. One of the popular annual species Chenopodium album was more frequent on young plantations than on older ones. The important weed species in bush plantations were perennials hard to be controlled with herbicides (Equisetum arvense, Taraxacum officinale), annuals with long time of emergence during the year (Poa annua, Senecio vulgaris, Stellaria media), annuals with a great number of seeds, which possess a high persistence in soil (Echinochloa crus-galli, Amaranthus retroflexus). A great number of perennials were described when plantations were established after orchards or old bush plantation. The absence of a chemical control of numerous perennials prior to bushes or strawberries planting increased the frequency of this weed group on young plantations. Trends of distribution of specific weed species are similar to bush plantations and orchard (Lisek, 1997, 1999). Minimum soil tillage affected this tendency. On localities near orchards Epilobium adenocaulon were noticed. Epilobium adenocaulon is a native of North America. For the first time it was found in Poland in 1917 and was described as a plant typical for forests (Szafer et al.,

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1988). 25 or 30 years ago this species was no problem (Tymrakiewicz, 1976). Now E. adenocaulon has strongly infested some orchards (Lisek, 1997) and probably can be spread on bush plantations. In last years a next perennial species - Rorippa sylvestris has infested arable crops, orchards and small fruit plantations. High precipitation in 1996-1998 in Poland influenced the invasion of R. sylvestris because this species prefers wet localisation (Tymrakiewicz, 1976, Szafer et al., 1988). On the bush plantation localised near roads and forests, the numerous seedlings of tree species, like Tilia, Acer and Betula were found. The kind of herbicide used influences the weed species spectrum (Mikulka & Chodová, 1999). Some weed species, for e.g. Conyza canadensis were selected as a result of a long-term use of triazines. Plantations infested with Conyza canadensis are becoming fewer in Poland every year because the use of triazines is limited. In the seventies this species was one of the most troublesome on bush plantations. Specific weed species were noticed on the blueberries plantations: Rumex sp., Equisetum arvense, Polygonum amphibium, Epilobium adenocaulon, Chamaenerion anguistifolium and Rorippa sylvestris. The trend of the distribution of these species was connected with low pH of the soil and with the use of organic mulches, which could not stop perennial plants growing. Respectively, great number of different weed species (130) on soft fruit plantations is connected with various methods of control. Integrated Fruit Production is a good model for weed control because it combines different methods, which can be useful depending on conditions. References Dessaint F., 1999. Species richness of weed communities: modelling its relation to the

environment. Proc. 11th EWRS Symposium, Basel Switzerland, 28 June-1 July 1999: 31. Lisek J., 1997. Sadowniczy atlas chwastów. ISK Skierniewice, 129 pp. Lisek J., 1999. Zwalczanie chwastów na plantacjach krzewów jagodowych. Proc. Conf.

Intensyfikacja Produkcji Owoców z Krzewów Jagodowych, Skierniewice Poland, 9 June 1999: 60-63.

Mikulka J. & Chodová D., 1999. Long-term changes in weed societies in the Czech Republic. Proc. 11th EWRS Symposium, Basel Switzerland, 28 June-1 July 1999: 34.

Szafer W., Kulczyński S. & Pawłowski B. 1988. Rośliny Polskie vol.1-2. PWN Warsaw, p. 1019. Tymrakiewicz W. 1976. Atlas Chwastów. PWRiL Warsaw, p. 439.


pp. 103 - 108

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Possibilities of efficient weed control in Integrated Production of soft fruits Jerzy Lisek Research Institute of Pomology and Floriculture, Department of Fruit Crop Management and Plant Nutrition, Pomologiczna 18, 96-100 Skierniewice, Poland Abstract: This paper contains results obtained in field experiments on weed control on small fruit plantations and describes cultural practices connected with weed control recommended for Integrated Production of Soft Fruits in Poland. Positive and negative sides of herbicide use, soil cultivation and mulching are mentioned. Specific problems with weed control in strawberries, currants, raspberries and blueberries – biological efficiency of different methods, selectivity of herbicides as well as technical possibilities are described. Phenmedipham alone or in mixtures with desmedipham and ethofumesate is recommended for strawberries. Napropamide is effective for weed control in newly planted fruit bushes. Clopyralid is a selective herbicide for blackcurrants. Key words: weeds, integrated control, herbicides, soft fruits Introduction The aim of the integrated method of weed control is both to minimise the use of herbicides and protect the soil from erosion. Strawberries and fruit bushes need weed control because of the competition for nutrients and water (Lawson & Wiseman, 1976). Persistent, residual herbicides are especially dangerous for the environment. Some herbicides recommend for standard production of strawberries and bush fruits are not suitable for Integrated Production. The time of degradation of lenacil in the soil is shorter than 6 months, but for simazine it is even longer than 15 months (Ragab & Leefe, 1972; Kostowska, 1982). Phenmedipham is a proper herbicide for weed control in strawberries since it has a good selectivity for this crop (Robinson & Rath, 1970; Uprichard, 1972; Niggli & Potter, 1988). Mixtures of phenmedipham and desmedipham, phenmedipham and ethofumesate or ethofumesate alone are used to broaden the spectrum of controlled weed species in strawberries (Clay, 1979, 1981, 1982; Lawson & Wiseman, 1980; Cox & Cerr, 1981). These active ingredients have a synergistic action on weeds and short a time of degradation in the soil and plants (Davis & Dubabek, 1973’ van Hoogstraten et al., 1974; Hammond et al., 1976; Tena et al., 1982). Napropamide is a safe and effective herbicide for winter application in various soft fruit crops (Walker et al., 1985; Lawson & Wiseman, 1987). Glyphosate-containing herbicides control perennial weeds prior to strawberries and bushes planting (Lisek & Chlebowska, 1993; Cianciara & Lisek, 1993). Clopyralid is selective for strawberries (Bailey & Clay, 1980) and is safe for black currants (Cianciara et al., 1988). Glufosinat-ammonium gave good control of both strawberry runners and weeds on bush plantations (Lawson & Wiseman, 1985; Cianciara et al., 1988). Quizalofop-p-ethyl is a selective herbicide for grasses control on soft fruit plantations (Cianciara, 1985).

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Material and methods Different methods of weed control: herbicide use, soil cultivation, mulching with plastic and straw were evaluated on plantations of strawberry, currants, gooseberry and blueberry. Herbicides were tested in experiments under field conditions carried out in the Pomological Orchard in Skierniewice (Central Poland). In 1994-1996 ready for use mixture of phenmedipham, desmedipham and ethofumesate (as Betanal Progress AM 180 EC - AgrEvo product containing 60 g/l of each active ingredients) was tested in strawberries. The efficiency of this mixture was compared with some standard methods, among others phenmedipham use (as Betanal 160 EC of AgrEvo) and hand weeding, on cv Senga Sengana strawberry plantation. The selectivity of phenmedipham, desmedipham and ethofumesate mixture for nine strawberry cultivars was evaluated, too. FDE mixture was applied three times (split applications) before the beginning of the flowering of strawberries. The usefulness of a few herbicides on small fruit plantations with the aim for Integrated Fruit Production was estimated in 1993-1999. Prior to strawberries and bushes planting, glyphosate (as isopropyloamine salt - Roundup 360 SL of Monsanto and trimethylsulfonium salt - Avans 330 SL of Zeneca Agrochemicals) were applied to kill perennial weeds. For this purpose, mixtures of glyphosate with MCPA (as Chwastox Extra 300 SL of Organika, Sarzyna) or 2,4-D (as Aminopielik Standard 600 SL - Rokita) and fluroxypyr (as Starane 250 EC of Dow Elanco) were used too. Glufosinate-ammonium (Basta 150 SL of AgrEvo) was applied to control weeds on bush plantations and runners in strawberries. The possibilities of use of napropamide (as Devrinol 450 SC of Zeneca Agrochemicals), clopyralid (as Lontrel 300 of Dow Elanco), quizalofop-p-ethyl (as Targa Super 5 EC of Nissan Chemical Ind.) were tested. The plots in the experiments were arranged in randomised blocks with four replications. The plot area was from 5 to 50 m2, but the number of cultural plants was no fewer than 16. Herbicide application was made in the volume of 300 l water/ha. Results and discussion Strawberries Proper forecrop with a strong competition and allelopathic effect on weeds and chemical weed control prior to planting decided in great extend about efficient weed control in newly planted strawberries. Cereals or white mustard (Sinapis alba) were recommended in practice as the best forecrop for strawberries. Herbicide treatment was useful for killing numerous perennial weeds before the setting of the plantation. Glyphosate (isopropyloamine and trimethylsulfonium salt) at the rate of 1.65-1.80 kg a. i. per ha gave good control of Agropyron repens and afforded better possibilities for good cropping in comparison with the plots where A. repens was not controlled, what confirms the results of the earlier experiments of Cianciara & Lisek (1993). Good control of broadleaf perennial weeds was obtained when glyphosate, at the above-mentioned doses, was mixed with herbicides containing MCPA or 2,4-D at the rates of 0,60-0,90 kg a. i. per ha. Mixtures with MCPA were more effective in control of Equisetum arvense and with 2,4-D in control of Achillea millefolium. Fluroxypyr at the rate of 0.50 kg a. i. per ha gave better control of broadleaf perennial weeds, e.g. Rumex sp., Taraxacum officinale, than glyphosate alone or in mixtures. If the time between glyphosate with MCPA or 2,4-D spraying was shorter than 5 - 6 weeks, the herbicides reduced the growth of strawberries causing leaf stunting, chlorosis and necrosis. Early postemergence treatment with phenmedipham or with the ready-to-use mixture of phenmedipham, desmedipham and ethofuseate (FDE) had the basic importance for efficient weed

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control. Results obtained in Skierniewice confirmed that phenmedipham alone or in a mixture with desmedipham and ethofumesate is useful to control weeds in strawberries (Robinson & Rath, 1970; Uprichard, 1972; Clay, 1979, 1981, 1982; Lawson & Wiseman, 1980; Cox & Cerr, 1981; Niggli & Potter, 1988). FDE mixture used in split application gave better control of many important annual broadleaf weeds and grasses than phenmedipham. This mixture at the recommended dose of (90+ 90+90 g a.i. per ha) triple, controlled efficiently such species as: Chenopodium album, Stellaria media, Senecio vulgaris, Capsella bursa-pastoris, Amaranthus retroflexus, Lamium purpureum, Viola arvensis, Polygonum aviculare, Poa annua, Echinochloa crus-galli, Setaria viridis. The growth and yield of newly planted strawberries cv Senga Sengana on the plots treated three times with FDE mixture was as good as that on the plots hand weeded (Tab. 1).

Table 1. Influence of a method of weed control on growth and yield of newly planted strawberries cv Senga Sengana (1994-1996)

Method of weed control

Mean fresh weight of strawberry plant (g)

Mean fruit yield in year

of planting (kg/plot) Untreated control Hand weeding FDE 60+60+60 g/ha x 3 FDE 90+90+90 g/ha x 3 FDE 120+120+120 g/ha x 3 Phenmedipham 960 g/ha Hand weeding + lenacil 800g/ha Black plastic mulching

34.4 a 65.5 d 46.1 abc 56.3 bcd 54.2 bcd 44.4 ab 53.8 bcd 60.8 cd

0.41 a 0.92 b

0.79 ab 0.92 b 0.90 b 0.84 b 0.85 b 0.98 b

Means followed by the same letter do not differ at 5% level of significance; Duncan's multiple range t-test

Effects of FDE treatment were observed on young leaves, which became stunted with clear chlorosis and necrosis. There were visible differences in tolerance of herbicides among nine plant cultivars. Senga Sengana, Dukat, Kama and Real were less damaged than Dana and Gerida. Cultivars Syriusz, Redgauntlet and Elsanta were intermediate. After non residual phenmedipham herbicide use or mechanical soil cultivation at the beginning of the flowering of strawberries, soil mulching with straw was recommended. This kind of mulch is sufficient to stop the emergency of annual weeds and it is necessary to get good quality strawberry table fruits. Soil covering with black plastic was connected with more difficulties than with straw. Black plastic increased the infection with fungal diseases and sun damages of fruits but did not fully prevent weed from emerging around strawberry plants. There were serious problems with utilisation of the old plastic. In the period of late July - September, mechanical soil cultivation with rotavator in interrows was the most efficient and suitable method of weed and strawberry runners’ control in Integrated Production The combination of various methods of weed control (adequate forecrop, limited use of non-persistent herbicides, straw mulching, mechanical soil cultivation) is an attractive model of strawberry management for Integrated Production and for the standard one as well.

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Currants, Gooseberry, Raspberry The kind of forecrop and chemical control of perennial weeds prior to bushes planting was similarly important as in strawberries. It was especially important in fields replanted after old plantations and areas uncultivated for some time. Spring and summer mechanical soil cultivation in interrows on young plantations within 2-3 years after planting proved useful. Weed control was the serious problem in the rows of bush fruit crops, particularly on big acreage of currants and gooseberry. Mechanical soil cultivation with tractor-powered machines was practically impossible. Soil mulching with plastic was not recommended for the same reason as on strawberry plantation and because of its high costs. Plastic was not an adequate kind of mulch on raspberry plantations where new canes in rows were needed. Tree bark was the best sort of organic mulch but its transportation and spread on the soil surface were costly. Mulching with straw or sawdust in some cases attracted rodents. Because of these problems, the use of napropamide in narrow (0.5-1.0 m) herbicide strips was recommended for young bush plantation. This soil-acting herbicide degrades quickly and is more adequate for Integrated Production than such herbicides as simazine, dichlobenil and pronamide, which are registered for fruit bush plantations in Poland. Napropamide was applied at low rates (1.35-1.80 kg a. i. per ha) because higher ones might be too persistent in the soil (Walker et al., 1985). Napropamide applied in winter or early spring controlled well annual grasses but was not satisfactory efficient for some broadleaf weeds, e. g. Brassicacea sp. and Lamium purpureum control (Lawson & Wiseman, 1987). Bushes grown on the plots treated with napropamide were in better condition in comparison with untreated control. It was visible first of all in raspberries, which are not tolerant of weed competition (Lawson & Wiseman, 1976). Low-growing perennial grasses (grasses/herbs) are usually established in interrows in the third year after bush planting, This method gave negative results in the central Poland, on sandy soils, with low precipitation (mean 524.0 mm per year). On these localisations frequent mowing of weeds was recommended. Perennial grasses in alleyways were more suitable in southern Poland, where rainfall is higher and in eastern Poland, on loamy soils. Similarly as in the earlier experiments (Cianciara, 1985; Cianciara et al., 1988), supplementary postemergence treatment in the bush rows with glufosinate-ammonium, quizalofop-p-ethyl and clopyralid gave good results on older plantations infested with perennial weed species. Clopyralid was useful not only for Matricaria sp., Anthemis sp. Chamomilla sp. but also for Cirsium arvense control (Bailey & Clay, 1980). This active compound controlled efficiently Equisetum arvense and Conyza canadensis at the stage of rosette. Clopyralid was safe for black currants, especially after the fruit harvest. Blueberry Specific problems with weeds on blueberry plantations were connected with the environmental requirements of this species and the cultural practices on plantations. Blueberry is grown on acidic and most often irrigated soils. The soil surface on plantations is mulched with tree bark, peat or plastic. In these conditions perennial weeds were dominant, mainly Equisetum arvense, Rorippa sylvestris, Rumex sp., Polygonum amphibium, Epilobium adenocaulon, Chamaenerion angustifolium. Mulching, especially with bark or peat, did not stop the growth of these species. Blueberry plantations management was connected with high economical costs and therefore the acreage of plantations was respectively smaller than other soft fruits crops. In these conditions, hand weeding under bushes was possible and efficient. Foliar treatments with glufosinate-ammonium, quizalof-p-ethyl and clopyralid was an additional method of weed control.

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References Bailey J.A. & Clay D.V., 1980. The safety and effectiveness of 3,6-dichloropicolinic acid for the

control of Cirsium arvense in strawberries. Proc. 1980 Brit. Crop. Prot. Conf.-Weeds: 321-328.

Cianciara T. 1985. Stosowanie powschodowych graminicydów do niszczenia perzu na plantacjach roślin jagodowych. Mat. z VII Spotk. Zesp. Herbicyd. KNO PAN:16-19.

Cianciara T., Chlebowska D. & Wójciak A., 1988. Stosowanie w praktyce nowych herbicydów do odchwaszczania plantacji roślin jagodowych. Mat. z X Spotk. Zesp. Herbolog. KNO PAN: 8-13.

Cianciara T. & Lisek J., 1993. Ocena przydatności preparatów 'Glyphogan' and 'CHE 3607' w uprawach sadowniczych. Mat. z XIV Spotk. Zesp. Herbolog. KNO PAN: 10-16.

Clay D.V., 1979. Weeds of strawberries. Knocking clover over. Grower 92: 24-30. Clay D.V., 1981. The tolerance of strawberries to ethofumesate: differences in varietal response

and effects of mixture with phenmedipham. Experimental Hortic. 32: 38-48. Clay D.V., 1982. The tolerance of strawberry cultivars to ethofumesate alone and in mixture with

lenacyl and phenmedipham. Proc. 1982 Brit. Crop Prot. Conf.-Weeds: 291-298. Cox T.I. & Kerr R.M., 1981. Tolerance of Tioga strawberry to foliar herbicides. New Zealand

Commercial Grower 36(3): 24. Davis D.G. & Dusbabek K.E., 1973. Effect of diallate on foliar uptake and translocation of

herbicides in pea. Weed Sci. 21: 16-18. Hammond C.H., Griffiths W., Hoogstraten S.D. van & Whiteoak R.J., 1976. The use of

ethofumesate in grass seed crops. Proc. 1976 Brit. Crop Protection Conf.: 657-663. Hoogstraten S.D. van, Baker C. & Horne S.D., 1974. Ethofumesate behaviour in the soil. Proc.

12th Brit. Weed Control Conf.: 503-509. Kostowska B., 1982. Zachowanie się herbicydów w glebie. Praca habilitacyjna. Inst. Uprawy

Nawożenia i Gleboznawstwa. Puławy. Lawson H.M. & Wiseman J.S., 1976. Weed competition in spring-planted strawberries. Weed

Research 16: 155-162. Lawson H.M. & Wiseman J.S., 1976. Weed competition in spring planted strawberries. Weed

Research 16 (5): 345-354. Lawson H.M. & Wiseman J.S., 1980. Herbicide programmes for spring-planted strawberries.

Proc. 1980 Brit. Crop Conf.-Weeds: 353-360. Lawson H.M. & Wiseman J.S., 1987. Evaluation of crop tolerance to napropamide applied as a

late winter treatment in strawberry and raspberry. Proc. Crop Protection in Northern Britain 1987: 389-393.

Lisek J. & Chlebowska D., 1993. Efficiency of herbicide Avans 480 SL for weed control prior to planting of small fruits and for killing old raspberry plants. Acta Hortic. 352: 579-582.

Niggli V. & Potter C.A. (1988) Ursachen von Herbizidschäden in Erdbeeren. Erwerbsobstbau 30 (7): 185-188.

Ragab H.T.M. & Leefe J.S. (1972) Residues in soils and strawberries resulting from simazine applications. Canad. J. Plant Sci. 52 (2): 147-149.

Robinson D.W. & Rath N., 1970. The use of phenmedipham in strawberries. Proc. 10th Brit. Weed Control Conf., pp. 803-807.

Tena R., Magallanes M. & Carrido R., 1982. Soil persistance of selected sugar-beet herbicides and their combinations with lenacil. Weed Research 23: 245-249.

Uprichard S.D., 1972. Tolerance of six strawberry varieties to phenmedipham applied shortly after planting. Proc. 11th Brit. Weed Control Conf.: 374-377.

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Walker A., Brown P.A. & Mathews P.R., 1985. Persistance and phototoxicity of napropamide residues in soil. Ann. Appl. Biol. 106: 323-333.

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Posters

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pp. 111 - 115

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Progress in breeding of blackcurrant (Ribes nigrum L.) for resistance to main fungal diseases at Research Institute of Pomology and Floriculture at Skierniewice, Poland Agata Broniarek-Niemiec, Stanisław Pluta, Anna Bielenin Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland Abstract: Field resistance of 53 blackcurrant genotypes (cultivars and breeding selections) to main fungal diseases (powdery mildew, leaf spot and white pine blister rust) was investigated during 1998-1999. Of the investigated genotypes only three cultivars – ‘Ben Lomond’, 'Ben Nevis' and 'Ceres' were very susceptible to powdery mildew. The rest of cultivars and breeding selections were highly resistance to this disease. None of the genotypes tested was resistant to leaf spot. Cultivar Titania and 17 selections had a full field resistance to white pine blister rust. Key words: blackcurrant, Ribes nigrum L., resistance, breeding, powdery mildew, leaf spot, white pine blister rust. Introduction Poland has been a leading producer of blackcurrant (Ribes nigrum L.) in the world for many years. Annual fruit production of this crop ranges between 100 - 130 thousand tons harvested from about 27 thousand ha (Ostrowska, 1998). The acreage of plantings has been increasing for last two years because of a big demand and good prices of fruits received by growers. 'Ojebyn', 'Titania' and 'Ben Lomond' are dominant cultivars on commercial plantations. However, besides many advantages those cultivars have also some deficiencies, such as susceptibility to fungal diseases: powdery mildew (Sphaerotheca mors-uvae Berk.), leaf spot (Drepanopeziza ribis Kelb.) and white pine blister rust (Cronartium ribicola Fish.) (Broniarek et al., 1997, 1999). Introduction of new cultivars resistant to these pathogens could reduce a number of the sprays with fungicides in the growing season. Reduced use of chemicals is required in the Integrated Pest Management (IPM) of soft fruits, which have been introduced into European plantations, including blackcurrant, since 1998 (Gajek 1998). For resolving these requirements and protection of our environment new blackcurrant breeding program was initiated at the Research Institute of Pomology and Floriculture in Skierniewice in 1986 (Pluta and Żurawicz, 1993). Breeding for resistance to main pest and diseases is the one of its main targets. The best, resistant genotypes are used as parental forms in crossing programs oriented on increasing the health status of breeding material. Young seedlings obtained from the crosses are inoculated with conidia of S. mors-uvae in a glasshouse. Then the seedlings are preliminary screened to eliminate susceptible ones at the early stage and resistant plants are planted in the field for further evaluation. The best individuals are vegetatively propagated and evaluated in the collection of selections (Pluta and Żurawicz, 1998; Pluta 1999). The main objective of this work was to determine the susceptibility of selected cultivars and breeding selections to main fungal diseases in the field conditions.

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Material and methods Blackurrant cultivars and breeding selections used in this experiment have been grown in two cultivar trials planted in 1994 and in 1995. Additionally, over 20 advanced selections originated from the breeding program and planted in the collection in 1997 were included in this investigation. Field experiments were carried out at the Experimental Orchard in Dąbrowice near Skierniewice (Central Poland). Trials were established in the random block design with 3 replication consisted of 3 shrubs per plot. Advanced selections were planted without replications and 3 plants were planted on an individual plot. No protection against diseases was applied. All the genotypes tested were evaluated in respect of field resistance to powdery mildew, leaf spot and white pine blister rust. The evaluations were done in late July and in the middle of August in 1998 and 1999, using a 5-point ranking scale (1 - no symptoms, 5 - very severe symptoms on leaves). The data were statistically elaborated by the analysis of variance (ANOVA). The significance of differences between means was estimated with Duncan’s "t" test at P=0.05. Results and discussion Field resistance of the genotypes tested to main fungal diseases is presented in Tables 1 and 2. Most of genotypes showed high resistance to powdery mildew. Only standard cultivar Ben Lomond and its sister seedling 'Ben Nevis' were very susceptible to this disease. In both years of investigation (1998-1999) level of infection of these cultivars ranged from 4.1 to 5.0 (Tab. 1). These results correspond to those obtained by Pederson (1998). Unfortunately, all the genotypes tested were susceptible to leaf spot. Levels of infection were different and ranged from 1.5 to 4.4. The least symptoms were observed on plants of four cultivars - Titania, Ben Nevis, Ben Sarek and Storklas and on breeding selections marked 138 x76/69A/1, 74020-6x/1, B.Lx7, B.Lx2, and PC-17. Levels of disease on these genotypes were scored from 1.5 to 3.0 in both seasons (Tab. 1). Infection of plants by white pine blister rust was rather low during the experiment. In 1998-1999 no symptoms of C. ribicola were observed on the standard cultivar Titania. Plants of this cultivar are highly resistant to this pathogen and similar results were reported by other authors (Pluta et al.1993). Among tested selections a high resistance to blister rust showed 11D/2, 138x76/69A/1, 74020-6x/1 and 83x80/1 (Tab. 1). Results of the resistance evaluation of breeding selections planted in the field collection are presented in Table 2. Of the genotypes tested only two cultivars - Ben Lomond and Ceres were susceptible to powdery mildew. In 1998-1999 symptoms of this disease were assessed from 2.5 to 5.0. Most of the cultivars tested and all breeding selections were highly resistant to S. mors-uvae (Tab.2). None of the genotypes tested was fully resistant to leaf spot. The relatively high field resistance to this pathogen was noticed on plants of a new cultivar Tisel (originated from our breeding program) and on breeding selections PC-241 and PC-421. For these genotypes the level of infection ranged from 2.0 to 2.5 (Tab. 2). Besides ‘Titania’, highly resistant to C. ribicola were also selections PC-223, PC-276, PC-290, PC-332, PC-335, PC-339, PC-401, PC-413, PC-421, PC-425 and PC-427 (Tab. 2).

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Table 1. Evaluation of the field resistance of blackcurrant genotypes grown in the cultivar trials to main fungal diseases (Experimental Orchard, Dabrowice, 1998-1999).

Level of infection*

Powdery mildew

Leaf spot White pine blister rust

Cultivar /selection

Origin

1998 1999 1988 1999 1998 1999 Cultivars trial planted in autumn of 1994 Ojebyn Unknown 1,0 a** 1,0 a 3,6 f-j 3,3b-e 2,6 cd 2,3 e-hTitania Altajskaja D. x (Consort x

Kajaanin M) 1,0 a 1,0 a 3,0 c-g 3,0 a-d 1,0 a 1,0 a

Ben Lomond (Consort x Magnus) x (Brodtorp x Janslunda) 4,3 b 4,3 b 3,7 g-k 3,4 c-e 1,3 a-c 1,7 c-f

Ben Alder Ben More x Ben Lomond 1,0 a 1,0 a 3,7 g-k 3,3 b-e 2,1 b-f 1,9 d-f Ben Nevis (Consort x Magnus) x (Brodtorp x

Janslunda) 4,1 b 4,1 b 3,0 c-g 2,9 a-d 2,3 b-f 1,9 d-f Ben Sarek Goliath x Ojebyn 1,0 a 1,0 a 2,7 c-e 2,8 a-c 1,0 a 1,8 c-f Ben Tirran Ben Lomond x N29/17 1,0 a 1,0 a 3,6 f-j 3,6 d-f 2.0 a-f 1,8 c-f Ben Connan Ben Sarek x Ben Lomond 1,0 a 1,0 a 3,1 d-h 2,7 a-c 1,2 ab 1,1 ab Storklas SunderbynII x (Consort x Kajaanin

M.) 1,0 a 1,0 a 3,0 c-g 2,9 a-d 2,0 b-f 1,6 b-e4D/10 Ben Nevis x Ojebyn 1,0 a 1,0 a 3,8 h-k 3,6 d-f 1,6 a-d 1,4 a-d11D/2 Biełoruskaja Sł. X Titania 1,0 a 1,0 a 3,0 c-g 2,9 a-d 1,0 a 1,0 a 26C/5 Titania x Ben Nevis 1,0 a 1,0 a 4,4 kl 4,2 fg 1,2 ab 1,2 a-c Ben Alder x/5 Ben Alder x op 1,0 a 1,0 a 3,0 c-g 3,0 a-d 3,1 f 3,0 g-j 138 x 76/69A/1

7/72 x Ceres 1,0 a 1,0 a 3,0 c-g 2,9 a-d 1,0 a 1,0 a

74020-6 x /1 Polar x op 1,0 a 1,0 a 2,6 cd 2,6 ab 1,0 a 1,0 a 210 x B. Alder/8

Titania x Ben Alder 1,0 a 1,0 a 4,8 l 4,7 g 2,6 d-f 2,3 e-h

Cultivars trial planted in autumn of 1994 Ojebyn Unknown 1,0 a 1,0 a 3,0 c-g 2,9 a-d 2,9 ef 3,1 hij Titania Altajskaja D. x (Consort x

Kajaanin M) 1,0 a 1,0 a 2,9 c-f 3,3 b-e 1,0 a 1,1 ab

Ben Lomond (Consort x Magnus) x (Brodtorp x Janslunda) 4,4 b 5,0 c 4,2 j-l 2,9 a-d 1,7 a-d 1,7 c-f

80 x 138/2 Ben Lomond x 7/72 1,0 a 1,0 a 3,4 e-j 3,0 a-d 1,5 a-d 3,2 ij B.T. x Tit./2 Ben Tirran x Titania 1,0 a 1,0 a 2,9 c-f 2,5 a 3,1 f 3,1 h-j Tit. X B.A/2 Titania x Ben Alder 1,0 a 1,0 a 3,2 d-i 3,2 a-e 1,4 a-c 2,1 d-f B.L x /7 Ben Lomond x op 1,0 a 1,0 a 2,6 b-d 2,5 a 2,3 c-f 3,3 j B.L x /2 Ben Lomond x op 1,0 a 1,0 a 1,5 a 3,0 a-d 1,2 ab 2,2 e-g83 x 80/1 Biełoruskaja Sł. x Ben Lomond 1,0 a 1,0 a 3,0 c-g 3,2 a-e 1,0 a 1,0 a PC-15 Ben Lomond x 7/72 1,0 a 1,0 a 2,3 bc 2,7 a-c 1,5 a-d 2,2 ef PC-17 Ben Lomond x 7/72 1,0 a 1,0 a 2,0 ab 2,5 a 1,7 a-e 2,4 f-i Explanations: * - ranking scale 1-5 where 1 – no symptoms, 5 – very severe symptoms on plants, ** - within columns means followed by the same letter do not differ significantly

according to Duncan’s “t” test at P=0.05.

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Genotypes with a high field resistance to main fungal diseases will be included in our blackcurrant breeding program for increasing the healthiness of a breeding material. The best selections inheriting resistance to these diseases as well as possessing high productivity, good quality of fruits and suitable plant habit will be given for the National Fruit Trials for the final evaluation before they will get the registration on the List of Cultivars. Table 2. Evaluation of field resistance of blackcurrant genotypes grown in collection of

selections to main fungal diseases (Experimental Orchard, Dabrowice, 1998-1999).

Level of infection* Powdery mildew

Leaf spot White pine blister rust

Cultivar /selection

Origin

1998 1999 1988 1999 1998 1999 Ojebyn Unknown 1,0 a 1,0 a 4,3 fg 4,0 e 2,3 cd 3,3 e Titania Altajskaja D. x (Consort x

Kajaanin M) 1,0 a 1,0 a 2,0 a 4,0 e 1,0 a 1,0 a

Ben Lomond (Consort x Magnus) x (Brodtorp x Janslunda) 5,0 c 4,8 c 4,7 g 4,0 e 2,3 cd 1,7 a-c

Bona Ojebyn x (R. dikuscha x Climax) 1,0 a 1,0 a 2,0 a 3,3 cd 1,0 a 2,6 de

Ceres (R. dikuscha x Barchatnaja) x op 2,5 b 4,3 b 4,0 ef 3,7 de 2,5 c-e 2,1 b-d

Tiben Titania x Ben Nevis 1,0 a 1,0 a 3,3 cd 4,0 e 3,0 e 2,2 cd Tisel Titania x self 1,0 a 1,0 a 2,0 a 2,3 a 1,6 b 1,3 ab PC-73 Consort x Ben Nevis 1,0 a 1,0 a 3,7 de 3,7 de 2,0 bc 3,0 de PC-95 Consort x Ojebyn 1,0 a 1,0 a 3,7 de 3,0 bc 3,0 e 2,0 b-d PC-106 Titania x Ben Nevis 1,0 a 1,0 a 2,0 a 3,0 bc 3,0 e 2,0 b-d PC-110 Ojebyn x Bieloruskaja Sl. 1,0 a 1,0 a 2,0 a 3,3 cd 2,6 de 2,8 de PC-223 (C/2/1/62 x Ben Alder) x

S12/1/117 1,0 a 1,0 a 3,0 c 3,0 bc 1,0 a 1,0 a PC-241 Bona x Titania 1,0 a 1,0 a 2,3 ab 2,3 a 1,0 a 1,2 a PC-275 (Ben Lomond x 7/72) x Ben

Nevis 1,0 a 1,0 a 2,0 a 3,0 bc 2,5 c-e 1,3 ab PC-276 Titania x Polar 1,0 a 1,0 a 2,5 b 3,0 bc 1,0 a 1,0 a PC-280 Titania x Ceres 1,0 a 1,0 a 3,0 c 3,5 c-e 1,0 a 1,0 a PC-287 Golubka x Titania 1,0 a 1,0 a 4,0 ef 2,5 ab 2,0 bc 1,0 a PC-290 Magnus x Ceres 1,0 a 1,0 a 3,0 c 3,0 bc 1,0 a 1,0 a PC-332 Ben Lomond x Polar 1,0 a 1,0 a 4,0 ef 3,0 bc 1,0 a 1,0 a PC-335 Ben Lomond x Polar 1,0 a 1,0 a 4,0 ef 3,5 c-e 1,0 a 1,0 a PC-339 S 47 x Ojebyn 1,0 a 1,0 a 3,5 c-e 3,0 bc 1,0 a 1,0 a PC-401 C1/9/10 x Ceres 1,0 a 1,0 a 4,0 ef 4,0 e 1,0 a 1,0 a PC-413 Golubka x Ri 74020-16 1,0 a 1,0 a 4,0 ef 2,5 ab 1,0 a 1,0 a PC-421 Titania x C2/15/40 1,0 a 1,0 a 2,5 b 2,0 a 1,0 a 1,0 a

PC-425 Titania x P/9/11/14 1,0 a 1,0 a 2,0 a 3,0 bc 1,0 a 1,0 a

PC-427 Titania x self 1,0 a 1,0 a 3,0 c 3,0 bc 1,0 a 1,0 a For explanations se see table 1.

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References Broniarek-Niemiec A., Pluta S., Bielenin A., 1997. Ocena polowej odporności porzeczki

czarnej i agrestu na podstawowe choroby grzybowe w hodowlanych kolekcjach roboczych ISK. Mat. z Ogólnopolskiej Konferencji Ochrony Roślin Sadowniczych: 135-136.

Broniarek-Niemiec A., Pluta S., Bielenin A. 1999. Wstępna ocena polowej odporności wybranych odmian i klonów hodowlanych porzeczki czarnej na podstawowe choroby grzybowe. Mat. VII Zjazdu Hodowców Roślin Sadowniczych, AR Lublin, 4-5. 02. 1999: 449-452.

Gajek D., Olszak R., Łabanowska B., H., 1998. Główne problemy integrowanej ochrony porzeczki czarnej przed szkodnikami w świetle wytycznych IOBC/wprs i ISHS. Mat. z Ogólnopolskiej Konferencji Ochrony Roślin Sadowniczych: 67-70.

Ostrowska K., 1998. Rozwój produkcji owoców jagodowych w Polsce. Mat. z XXXVII Ogólnopolskiej Naukowej Konferencji Sadowniczej: 227-235.

Pedersen H.L., 1998. Field resistance of black currant cultivars (Ribes nigrum L.) to diseases and pests. Fruit Varieties Journal 52: 6-10.

Pluta S., Żurawicz E.,1993. Black currant (Ribes nigrum) breeding program in Poland. Acta Hortic. 352: 447-453.

Pluta S., Żurawicz E., 1998. Wyniki ostatnich dziesięciu lat hodowli odmian porzeczki czarnej w Polsce. Mat. z Ogólnopolskiej Konferencji Ochrony Roślin Sadowniczych: 145-150.

Pluta S., 1999. Perspektywy hodowli nowych odmian porzeczki czarnej i agrestu. Mat. z Konferencji “Intensyfikacja Produkcji Owoców z Krzewów Jagodowych”, 09. 06. 1999, ISK Skierniewice: 3-12.

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pp. 117 - 118

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Resistance of strawberry cultivars to fungal diseases Valda Laugale, Inga Moročko Pūre State Horticultural Research Station, Pūre, Tukuma raj. LV-3124, Latvia Abstract: The spread and severity of fungal diseases were studied on 2 standard and 10 newly introduced strawberry cultivars in field conditions. The aim of study was to evaluate susceptibility of newly introduced strawberry cultivars to fungal diseases in Latvian conditions. In the trial cultivar `Jonsok` had the lowest resistance to fungal diseases. Key words: strawberry, cultivar, diseases Introduction Strawberries are one of the most popular commercial crops nowadays in Latvia and there is a tendency to increase plantations area even more. Many new, little known cultivars emerge on Latvian market but not all of them are suitable for growing in Latvian conditions. Cultivar’ susceptibility to diseases could vary in different growing areas. Therefore, it is important to test newly introduced cultivars before using them for commercial growing. Special attention should be paid to dangerous strawberry diseases (Phytopthora fragariae, Phytopthora cactorum, Verticillium sp.), which are still not spread in Latvia but could be brought in with imported planting material. Materials and methods The testing had been done at Pūre State Horticultural Research Station in 1998-1999. 10 newly introduced strawberry cultivars were evaluated and compared with two standards `Zefyr` and `Senga Sengana`. Assessments were done 2 times per season; in spring-summer and summer-autumn periods. The spread of disease was expressed as a percent of damaged plants of a given cultivar and severity was evaluated visually as a percent of damaged leaf surface. The following scale was used for evaluation of leaf spot: 0.0 % – plants without spots; 0.1 % – 1 spot per plant; 1.0 % – 10 spots per plant; 25.0 % – 1/4 of plant surface damaged; 50.0 % – 1/2 of plant surface damaged; 75.0 % – 3/4 of plant surface damaged; 100.0 % – all leaves dead. For evaluation of wilt 2-point scale was used: plant with symptoms of wilt and plant without any symptoms. Results and discussion The following fungal diseases were observed on strawberry cultivars tested: white spot (Ramularia tulasnei Sacc.), leaf scorch (Marsonina fragariae (Lih.) Kleb.), grey mould (Botrytis cinerea) on leaves and verticillium wilt (Verticillium sp.). In the previous observations it was noted that root and vascular tissue diseases are not widespread in Latvia (Dūks, 1976). Only on some plantations verticillium wilt was observed. In this trial wilt symptoms were noted on cultivars Pandora, Pegasus, Laura, Eros, Emily,

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Lambada, Zefyr, Jonsok and Bounty (Tab. 1). The highest number of damaged plants (15.2 %) was assessed on Emily cultivar. Table 1. The spread and severity of fungal diseases on strawberry cultivars (average for 1998-

1999)

White spot (%) Leaf scorch (%) Grey mould on leaves (%)

Cultivar

Spread of wilt

(%) severity spread severity spread severity spread Pandora 2.1 12.6 73.7 0.2 6.3 0.3 9.3 Pegasus 4.4 11.1 95.6 2.8 20.1 0.7 11.9 Laura 3.9 17.5 92.4 6.6 22.1 0.5 7.5 Eros 0.4 6.9 74.8 0.1 1.3 0.1 2.1 Emily 15.2 5.6 74.9 0.9 13.6 0.8 2.5 Eldorado 0.0 16.0 88.8 0.2 1.9 0.1 0.4 Lambada 2.8 36.1 91.0 1.9 19.6 0.1 1.3 Honeoye 0.9 9.5 90.6 2.6 30.0 0.1 1.7 Zefyr 0.4 7.9 95.0 1.1 13.8 0.1 2.5 Senga Sengana 0.0 9.4 95.8 0.4 4.6 0.4 7.4

Jonsok 0.4 10.6 100.0 4.5 37.9 0.9 24.2 Bounty 1.7 8.6 94.5 1.4 17.9 0.4 10.5

White spot is one of the most widespread strawberry diseases (Delhomez et al., 1995). Severity of disease depends on a cultivar and growing conditions. White spot was the most common of all strawberry diseases assessed this trial, too. One average, more than 70% of plants of all cultivars tested were infected whereas in cultivar Jonsok infected were all plants (100 %). Generally, severity of this disease was low because tested plants were young (1st and 2nd year after planting). Disease is usually more spread on the older and weaker plants. On average, during 2 years of experiment the most severe white spot damage was observed on cultivar Lambada (36.1 % of leaf surface damaged). The spread of leaf scorch varied from 1.3 to 37.9 %, depending on a cultivar. Severity of disease on all cultivars was low (less than 7.0% of leaf surface infected). Cultivars Laura and Jonsok were more severely damaged than the others. Grey mould damage was observed on plant leaves, too. Plant residues, especially those infected with grey mould, are the main source of infection for flowers and berries (Sosa-Alvarez et al., 1995). `Jonsok` was more severely infected with grey mould than the other cultivars tested in our trial. References Delhomez N., Carisse O., Lareau M., Khanizadeh S. 1995. Susceptibility of strawberry

cultivars and advanced selections to leaf spot caused by Mycosphaerella fragariae. Hort. Science 30: 592-595.

Dūks V. 1976. Zemenes. pp. 76. Sosa-Alvarez M., Madden L.V. and Ellis M.A. 1995. Effects of temperature and wetness

duration on sporulation of Botrytis cinerea on strawberry leaf residues. Plant Disease J. 79: 609-615.


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Preliminary studies on resistance of some strawberry cultivars to spider mite Tetranychus urticae Valentina Petrova*, Zigrida Čudare*, Ineta Šteinite**, Valda Laugale*** * Institute of Biology of Latvian University, Miera str.3, Salaspils, LV-2169, Latvia, e-

mail [email protected] ** National Botanical Garden, Miera str.1, Salaspils, LV-2169, Latvia, e-mail invitro@

latnet.lv *** Pure State Horticultural Research Station, Tukuma raj., LV-3124, Latvia Abstract: Seven commercial strawberry cultivars, Senga Sengana, Tenira, Korona, Induka, Kokinskaja Pozdnaja, Venta, Zefyr, were evaluated in field tests for resistance to the spider mite Tetranychus urticae Koch (Acari: Tetranychidae) in 1998. According to the mean number of the mites per leaf and the percentage of the plants infested with T. urticae during the season, the early cultivar Zefyr, medium-late Tenira and medium-early Venta were less susceptible to the spider mite in field tests than medium-early cultivar Korona, late cultivar Kokinskaja Pozdnaja and medium-late Senga Sengana. Key words: strawberry, spider mite, resistance Introduction

The mite Tetranychus urticae Koch is an important strawberry pest due to its nearly world- wide distribution and damage caused to strawberry.There is some knowledge obout resistance of strawberry to T. urticae. Rodriguez et al. (1970) recorded highly significant positive correlation between foliage nitrogen and mite’s injury in the individual strawberry clones. Differences in resistance to T. urticae among strawberry cultivars have been found by Eastbrook et al. (1997) in laboratory experiments, in which mite fecundity and development times were assessed.

Authors of the presented work studied resistance of strawberry to phytophagous mite T. urticae in field tests in the northwestern part of Latvia. Material and methods Seven commercial cultivars of Fragaria x ananasa: Induka, Korona, Kokinskaja Pozdnaja, Senga Sengana, Tenira, Venta, Zefyr were selected for this study. The two-year-old plants grown on the strawberry fields of the Pure State Horticultural Research Station were naturally infested with spider mite T. urticae. Samplings of foliage were made in May, June, July, August and September during the season of 1998. Samples consisted of 100 randomly selected trifoliate leaves - one leaf from one plant. The leaves were collected in separate plastic bags and stored at 4° ± 1° until counted. The number of mites at each life stages: egg, juvenile, adult males and females was recorded after direct counting under dissecting microscope. Clusters of 5 eggs, larvae or protonymphs were counted as one adult.

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Result and discussion The number of plants infested by two-spotted spider mite T. urticae varied for strawberry field age and developmental stage of a plant. We found that in May 1998 the average density of mite population was lower (15 mites/leaf) on two-year-old plants than on one-year-old plants (23 mites/leaf).

Early in a season the samplings showed that spider mites colonised from 5% to 85% of strawberry plants, depending on a variety. Average data obtained from one sampling showed that the spider mite colonised 35% strawberry plants in May, 44% in June and 37.6% in July 1998. After harvesting the strawberry plants hosted mites in smaller number than in the earlier period: 14.3% in August and 10.3% in September 1998.

Differences in resistance to phytophagous mite T. uricae among seven field-grown evaluated strawberry cultivars of have been found. More resistant to spider mite were early cultivar Zefyr and partially medium-late cv. Tenira and medium-early cv. Venta (Fig. 1, 2). More susceptible cultivars, according to our estimation, were medium-early Korona and partially late Kokinskaja Pozdnaja and medium-late cv. Senga Sengana (Fig. 1, 2). Resistance of cv. Induka to T. urticae was intermediate. The number of plants with the pest (29.5%) and mite population density (2.4 mites per leaf) on strawberry cv. Induka were the same as average values (28.4% and 2.5 mite per leaf respectively) obtained from whole experimental field with more than 30 strawberry cultivars (Fig. 1, 2).

Correlation between time of fruit ripening and cultivars’ resistance to T. urticae was not. Strawberry cultivars with resistance to pests and diseases may become alternative to

pesticides or may allow to decrease pesticide application on strawberry using the biological and other non-chemical methods.

Figure1. Number of plants infested by T.urticae on some strawberry cultivars.

7,711,7 14

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References Eastbrook, M.A., Crook, A.M.E., Cross, J.V. and Simpson, D.W., 1997. Progress towards

integrated pest management on strawberry in the United Kingdom. In: Proc. Third Inter. Strawberry Symp., Veldhoven, The Netherlands, 1996, vol. 2, Acta Horticulturae 439: 899-904.

Rodriguez, J.G., Chaplin,C.E., Stoltz, L.P., and Lasheeen, A.M., 1970. Studies on resistance of strawberries to mites. I. Effects of plant nitrogen. J. Econ. Entomol.: 63(6): 1855-1858.

Figure 2. Population density of T. urticae on some strawberry cultivars.

0,71,2

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pp. 123 - 126

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Progress in selection of blackcurrant cultivars suitable for integrated mite management Dariusz Gajek, Stanisław Pluta, Edward Żurawicz Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland Abstract: Resistance of blackcurrant cultivars and breeding clones to blackcurrant gall mite and two-spotted spider mite was investigated. It was found that of 70 tested genotypes only two cultivars – ‘Ceres’ and ‘Titania Z’ were fully resistant to the gall mite. No symptoms of this pest feeding were also found on four clones originated from Polish breeding programme: 1\4, 7\9, 7\13 and 12\32. It was also proved that blackcurrant genotypes differed in susceptibility (infestation level) to two-spotted spider mite. Of the cultivars tested ‘Ben Lomond’ was quite heavily infested in comparison with other genotypes whereas cv. ‘Ben Tirran’ showed very low level of infestation with this pest. Key words: blackcurrant, Ribes nigrum L., breeding, cultivar, resistance, blackcurrant gall mite, two-spotted spider mite, IPM Introduction Two species of mites – gall mite (Cecidophyopsis ribis Westw.) and two-spotted spider mite (Tetranychus urticae Koch) are very dangerous pests of blackcurrants grown in Poland. (Łabanowska and Gajek, 1994; Gajek et al., 1996; Czajkowska and Kropczynska, 1996). Breeding of cultivars resistant to the blackcurrant gall mite and low intensity of infestation with the two-spotted spider mite can provide an opportunity for successful integrated management of these pests (Gajek 1995; Gajek et al., 1999).

The aim of the studies was selection of such cultivars and breeding clones originated from Ribes breeding programme realised at the Research Institute of Pomology and Floriculture in Skierniewice, Poland. Materials and methods Studies on selection of blackcurrant cultivars resistant to gall mite were conducted on two experimental plots at the Experimental Orchard in Skierniewice (Central Poland). They comprised above 70 genotypes of different origin and advanced selections obtained from Polish breeding programme. All planting material was artificially infested with the pest during its migration period (April-May). Infestation was done by hanging infested buds on newly-grown shoots of tested genotypes. Cultivars, which did not show any symptoms of gall mite feeding in the first screening were infested again.

Investigation on the rate of two-spotted spider mite infestation was carried out in 1998-1999 on two variety trails (trail I and trail II) planted at Dabrowice Experimental Station near Skierniewice. No artificial infestation and no pest control was applied. Population density of the mite was determined three times in each season (June, July and August).

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Results and discussion Blackcurrant gall mite During four years of investigations only two cultivars: Polish ‘Ceres’ and ‘Titania Z’ (genotype of unknown origin) did not show any symptoms of the pest infestation (Tab. 1). Table 1. Infestation rate of some blackcurrant breeding selections and cultivars with the gall

mite (Cecidophyopsis ribis Westw.); (Experimental Orchard, Skierniewice 1999) Culivar/ Breeding selection

Parentage

Average number of infested buds

per shrub Evaluation since 1996 Ojebyn Titania Ben Lomond Ben Alder Tisel Ceres Titania Z Evaluation since 1997 1/4 87/XVI/23/34 92/69A x 76/69A/22 87/XVI/23/14 87/I/2 87/V/6/1 92/69A x 76/69A/20 210 x 169/13 92/69A x 76/69A/31 7/2 213 x 76/69A/26 213 x 76/69A/41 213 x 76/69A/35 7/13 XXII/52 7/9 12/32 XXII/46 7/10 12/27 138 x 76/69A/7 92/69A x 76/69A/8

Unknown Altajskaja D. x (Consort x Kajaanin M.) (Consort x Magnus) x (Brodtorp x Janslunda) Ben More x Ben Lomond Titania x self. (R. dikuscha x Barchatnaja) x op Unknown (C2/1/62 x Ben Alder) x EM B1834/145* Ben Lomond x 7/72 Bona x Ceres Ben Lomond x 7/72 Gołubka x Fertodi – 1 Ojebyn x Titania Bona x Ceres Titania x Ojebyn Bona x Ceres S12/3/83 x EM B1834/113 Triton x Ceres Triton x Ceres Triton x Ceres S12/3/83 x EM B1834/113 Unknown S12/3/83 x EM B1834/113 S13/14/9 x EM B1834/67 Unknown S12/3/83 x EM B1834/113 S13/14/9 x EM B1834/67 7/72 x Ceres Bona x Ceres

8,9 16,4 91,4 49,3 9,2 0,0 0,0

0,0 3,0 0,5 0,4 0,8 0,5 0,1 0,4 6,0 0,7 0,1 0,5 0,5 0,0 5,4 0,0 0,0 2,4 0,3 0,4 2,1 1,7

Explanation: breeding selections marked EM B1834 obtained in East Malling, England, (released from backcrosses – “BC” of blackcurrant x gooseberry, inherited a gene Ce for resistance to gall mite)

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The first one has already been recommended for small plantings and home gardens in Poland. Three Polish clones resulted from crossings with ‘EM’ breeding lines (originating from East Malling) had no buds inhabited with the mite. These were 1\4, 7\9, 7\13 and 12/32. Other valuable traits of these genotypes are being presently evaluated in the collection. Their market usefulness has not been known so far but they should certainly be used as sources of resistance to the gall mite in further breeding programmes (Gajek et al., 1999). Two-spotted spider mite Obtained results showed that none of the tested cultivars or clones was fully resistant to the two-spotted spider mite (Tab. 2). Population of the pest was generally low and differences in its number on genotypes tested were rather small. It was observed that cv. ‘Ben Lomond’, recommended recently for growing in Poland, was quite heavily infested with the pest on both experimental plots. Low infestation level was ascertained on another, commonly grown in Europe cultivar - ‘Ben Tirran’. In comparison with other genotypes, the rate of its infestation was the lowest (Trial I). Adequately low susceptibility of this cultivar to infestation with two-spotted spider mite was also shown in another study (Gajek 1995). Among tested selections, low infestation level with this pest was also observed on Tit. x B.A./2, PC-20 and PC-26. Table 2. Intensity of blackcurrant infestation with two-spotted spider mite (T. urticae Koch)

(Experimental Station at Dąbrowice, 1999)

Trail I Trail II Average number of mites

per 10 leaves in season Average number of mites

per 10 leaves in season Cultivars / breeding selection

1998 1999

Cultivars / breeding selection

1998 1999 Ojebyn Ben Lomond Titania Ben Nevis Ben Alder Ben Tirran Nr.14 SCRI C2/1/62x/3 80x138/2 B.T.xTit./2 Tit.xB.A./2 B.Lx/7 80xself/1 B.A.x/1 83x80/2

2,1 abc* 3,8 abc 3,2 abc 7,9 c 0,8 ab 0,3 a 4,1 abc 2,1 abc 3,5 abc 5,5 bc 2,2 abc 6,6 c 5,0 abc 3,9 abc 1,7 ab

3,9 abc 7,1 bc 4,4 abc 4,3 abc 2,2 ab 1,6 a 3,6 abc 5,0 abc 6,7 bc 3,0 ab 1,7 a 5,9 abc 9,2 c 4,4 abc 5,6 ab

Ojebyn Ben Lomond Titania Lentaj Sjuta Kijewskaja Czereszniewa Czornyj Zemczug Sanjuta PC-1 PC-3 PC-8 PC-9 PC-20 PC-26

3,9 abc 9,6 abcd 5,6 abcd 6,5 abcd

15,2 bcd 3,9 b abc 2,3 a

16,7 cd 8,7 abcd 8,8 abcd

19,4 d 3,0 ab 1,5 a 1,9 a

1,9 a 5,3 ab 2,7 a 2,5 a 3,4 a 6,5 ab 4,4 a

11,4 b 6,0 ab 2,9 a 3,2 a 2,1 a 3,4 a 1,9 a

Explanation:* - means in columns followed by the same letter are not significantly different (P=0.05), Duncan’s multiple range test References Czajkowska, B., D. Kropczynska. 1996. Life-history parameters of T. urticae Koch on

selected cultivars of black currant. IOBC/wprs Bulletin 19(4): 347-348.

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Gajek, D. 1995. The intensity of the two-spotted spider mite (Tetranychus urticae Koch) on some new black currant cultivars. In: The Acari, Physiological and Ecological Aspects of Acari-Host Relationship. Warszawa: 505-509.

Gajek, D., J. Nowacki, J. Boczek. 1996. Black currant cultivars resistant to the gall mite (Cecidophyopsis ribis Westw.) as an element of integrated pest management. IOBC/wprs Bulletin 19(4): 349-350.

Gajek, D., S. Pluta, E. Żurawicz. 1999. Wstępne wyniki badań nad hodowlą odmian porzeczki czarnej odpornych na wielkopąkowca (Cecidophyopsis ribis /Westw./). Materiały VIII Ogólnopolskiego Zjazdu Naukowego Hodowców Roślin Ogrodniczych, "Hodowla Roślin Ogrodniczych u progu XXI wieku, Lublin 1999, T. II: 475-479.

Łabanowska, B.H., D. Gajek. 1994. Control of the two-spotted spider mite (Tetranychus urticae Koch) on black currant. 'Sixth International Symposium on Rubus and Ribes', Skierniewice, Poland, July 3-10, 1993. Acta Hortic. 352: 583-585.


pp. 127 - 129

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Side effect of fungicides used in Botrytis control on occurrence of leather rot of strawberry Anna Bielenin, Beata Meszka Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland Abstract: Some fungicides used against grey mould control also or reduce other pathogens. Leather rot caused by Phytophthora cactorum is a new disease on our plantation. This disease is most severe during years with prolonged rainy and cloudy periods during blossom and harvest. The purpose of this study was to compare the effect of some fungicides used in grey mould control program on occurrence of leather rot of strawberry under field conditions.

On untreated plots only a few rotted fruits were found. Also sprays with Euparen 50 WP and Sumilex 500 SC did not increase level of infection compared to the control. A heavy infection of fruits was observed on plots treated with Rovral Flo 255 SC and Teldor 500 SC. Key words: leather rot, grey mould, fungicides, strawberries. Introduction Grey mould (Botrytis cinerea Pers.) is the most important disease of strawberry. Usually 3-4 treatments are needed for its control. Some fungicides used against grey mould control also or reduce occurrence of other pathogens. Leather rot caused by Phytophthora cactorum (L&C) Schroet. is a new disease on our plantation. The first time a severe infections of fruit was noted in 1995. After this time disease was observed at a high level on several plantations. In the world leather rot is well known from many years. First the disease was reported by Rose in 1924 (Rose, 1924). Since that time leather rot has been found in Europe and Asia (Madden, 1991). The disease is most severe during years with prolonged rainy and cloudy periods during blossom and harvest. Such weather was in central Poland in 1996 and 1999.

Phytophthora cactorum infects fruits at all stages of development (Ellis, 1983). Rotted areas on green fruits are usually yellow-brown to dark brown. Ripening fruits after infection change a little in colour or may show discoloration ranging from light brown to dark purple or brown. Moreover, fruits affected by leather rot have an unpleasant odour and taste.

The purpose of this study was to compare the effect of some fungicides used in grey mould control program on occurrence of leather rot of strawberry under field conditions. Material and methods The investigation was carried out on plantation of strawberry cv. Senga Sengana in 1996 and 1999 in the Experimental Orchard in Dąbrowice and on private farm in Skierniewice. Plots were one-sided treated with four fungicides: Sumilex 500 SC (procymidone), Euparen 50 WP (dichlofluanid), Rovral Flo 255 SC (iprodione) and Teldor 500 SC (fenhexamid). The experiment was set up on an area of about 64 m2 per treatment. The sprays were made with motor knapsack sprayer "Solo" using 600 l/ha. The sprays started at the beginning of blossom and continued every 5-7 days.

Evaluation of grey mould and leather rot infections in field during harvest and after 24 hours

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of storage at room temperature (about 20o C) was made twice during harvest on 400 randomly chosen fruits per treatment.

The results were evaluated statistically by a analysis of variance and the significance of differences was estimated by Duncan' s test at P=0.05. Table 1. Percent of strawberry fruits cv. Senga Sengana affected by grey mould and leather rot in

different fungicide programmes Experimental Orchard, Dąbrowice 1996

Percent of affected fruits in the field and after 24 hrs storage at 200 C

Grey mould Leather rot

Fungicide and rate per 1 ha

20.VI. 3.VII. 20.VI. 3.VI. Untreated 25.7 b 80.3 c 0.3 a 1.9 a Euparen 50 WP 5.0 kg 8.8 a 47.2 b 1.3 ab 1.6 a Rovral Flo 255 SC 2.5 l 7.7 a 17.7 a 2.3 b 21.6 b

Dates of treatment: 20, 27.V., 3, 7.VI. Table 2. Percent of strawberry fruits cv. Senga Sengana affected by gray mould and leather rot in

different fungicide programs Private farm, Skierniewice 1999

Percent of affected fruits in the field and after 24 hrs storage in 200 C

Grey mould Leather rot

Fungicide and rate per 1 ha

16.VI. 22.VI. 16.VI. 22.VI. Untreated 67.7 d 81.3 c 0 a 0.4 a Sumilex 500 SC 1.5 l 4.9 a 2.3 a 0 a 0.9 a Euparen 50 WP 5.0 kg 4.6 a 7.0 a 0 a 0.4 a Teldor 500 SC 1.5 l 18.9 b 8.6 a 0 a 32.0 c

Dates of treatment: 17, 21, 31.V., 1.VI. Results and discussion Both seasons, when leather rot was observed at a high level, were characterised by a prolonged wet period during the harvest. Such weather was favourable also for grey mould infection. The level of this disease was extremely high in the second part of harvest period in 1996 and during almost whole 1999 season. 26% and later 80% of fruits were affected on untreated plots in 1996 and in 1999 68% and 81%, respectively. Fungicides used gave a good control of grey mould at the beginning of harvest time.

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Occurrence of leather rot in grey mould control experiments provided possibility to check the effect of used fungicides against Phytophthora cactorum. On untreated plots only a few rotted fruits were found. Also sprays with Euparen 50 WP and Sumilex 500 SC did not increase level of infection compared to the control. A heavy infections of fruits were observed on plots treated with Rovral Flo 255 SC and Teldor 500 SC. On these plots the percentage of fruits with leather rot symptoms was higher than fruit with grey mould infection (Tab. 1, 2).

Similar effects with iprodione or vinclozolin treatments obtained Jordan at al. (1977). They showed that fruit rot caused by Phytophthora cactorum was significantly increased on plants treated with these products. Leather rot is still only occasionally problem in our commercial fields. The most important in its control is to reduce periods of free moisture presence on fruit surface ( Ellis,1996). But also correct selection of fungicides against grey mould is necessary on the plantations with leather rot problem. Conclusion 1. Fungicides Rovral Flo 255 SC and Teldor 500 SC used in grey mould control program caused

the increase of leather rot on strawberries. This effect it was not observed with Sumilex 500 SC and Euparen 50 WP.

2. Correct selection of fungicides against grey mould is necessary on plantations with leather rot problem

References Ellis M.A., Grove G.G. 1983. Leather rot in Ohio Strawberries. Plant Disease 67: 549. Ellis, M.A. 1996. Integrated management of Botrytis "gray mold" and leather rot of strawberry.

Pennsylvania Fruit News 76 (4): 129-135 (abstr.). Jordan V.W.L., Pappas A.C. 1977. Inoculum suppression and control of strawberry Botrytis.

Proceedings 1977 British Crop Protection Conference-Pests and Diseases 2: 341-348. Madden L.V., Ellis M.A., Grove G.G., Reynolds K.M., Wilson L.L. 1991. Epidemiology and

control of leather rot of strawberries. Plant Disease 75 (5): 439-445. Rose D.H. 1924. Leather rot of strawberries. J. Agric. Res. 28: 357-376.

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pp. 131 - 132

131

Occurrence and identification of strawberry green petal phytoplasma Mirosława Cieślińska, Barbara Zawadzka Institute of Pomology and Floriculture, Department of Plant Protection, Virology Laboratory, Pomologiczna 18, 96-100 Skierniewice, Poland Abstract: Strawberry plants cvs Mara des Bois, Selva, Evita and Tango with symptoms suggestive of phytoplasma disease were identified on experimental and productive fields. Transmission of phytoplasma from infected strawberries to Catharanthus roseus was carried out using dodder. For detection of the pathogen the polymerase chain reaction (PCR) was applied. Several weeks after transmitting of SGP phytoplasma from strawberry, the deformation of leaves and flowers of Catharanthus roseus were observed. When the primers fU5/rU3 were applied in PCR reaction, DNA fragments of the expected sizes were amplified from Mara des Bois, Tango, Selva, Evita cvs. strawberry, Catharanthus roseus infected with SGP phytoplasma and positive control. No amplification products were observed in the sample containing DNA from healthy (asymptomatic) strawberry with all of the primers used. SGP could be hardly detected in the spring and summer. Key words: phytoplasma, strawberry green petal, polymerase chain reaction Introduction Strawberry green petal phytoplasma (SGP) is placed in aster yellows 16S rRNA taxonomic group I, subgroup C (clover phyllody and related phytoplasmas) (Gundersen et al, 1996). SGP is transmitted by leafhoppers and by infected plant material. SGP frequently show diagnostic symptoms on flowers, which petals become green eventually pink. The petals are lower than normally and frequently become leaf-like (phylloids) and sterile. The fruits of infected plants are small, hard, dwarfed and does not ripen. New foliage is dwarfed, asymmetric, with chlorotic margins. Leaf petioles are very short. Most of the infected plants die after a few months. Incidence of the disease varies from year to year (Posnette and Chiykowski, 1987). Material and methods Strawberry plants cvs Mara des Bois, Selva, Evita and Tango with SGP symptoms were found on experimental and on productive fields in 1998-99. Transmission of phytoplasma from infected strawberries to Catharanthus roseus was carried out using dodder.

For detection of the pathogen the polymerase chain reaction (PCR) was applied. DNA was isolated from 0.5 g samples of leaves petioles and midribs according to Ahrens and Seemüller (1992) procedure. Extracted DNA was used in PCR reactions. 35 PCR cycles in thermocycler (95oC for 45s., 55oC for 45s., 72oC for 1min. 20s.) were performed followed by a final elongation for 10 min. at 72oC.

At the first experiment three pairs of primers were used. Primers fU5/rU3 (Lorenz et al, 1995) are known to be the universal for phytoplasma and amplify 874 bp fragment; primers fAT/rAS (Kirkpatrick et al., 1994) - amplify 530 bp fragment and are specific for apple proliferation and primers fPD/rO1 (Lorenz et al, 1995) are specific for DNA of pear decline phytoplasma. For the next experiments fU5/rU3 primers were chosen. For the analysis of the amplification products 20 µl of the post PCR mixture were subjected to electrophoresis in a

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1% agarose gel in TBE buffer. The DNA was visualised under UV light after staining with ethidium bromide. Results Strawberry plants with symptoms suggestive of phytoplasma disease were identified on experimental and productive fields. The observed symptoms are similar those described by Posnette and Chiykowski (1987). Several weeks after transmitting of SGP phytoplasma from strawberry by dodders the deformation of leaves and flowers of Catharanthus roseus were observed. Infected plants were stunted and the petals of their flowers became green.

When the primer pair fAT/rAS was used in PCR no visible amplification products were obtain with any of the strawberries but a DNA fragment of 530 bp was produced from apple infected with proliferation phytoplasma (positive control). There was no amplification of DNA isolated from strawberries , C. roseus and apple with proliferation symptoms when the fPD/rO1 primers were used in PCR.

When the primers fU5/rU3 were applied DNA fragments of the expected sizes were amplified from Mara des Bois, Tango, Selva and Evita cvs strawberry, Catharanthus roseus infected with SGP phytoplasma and positive control. No amplification products were observed in the sample containing DNA from healthy (asymptomatic) strawberry with any of the primers used. It was hard to detect the SGP in the spring and summer.

References

Ahrens U., Seemüller E., 1992. Detection of plant pathogenic mycoplasmalike organisms by

the polymerase chain reaction that amplifies a sequence of the 16 S RNA gene. Phytopathology 8: 828-832.

Gundersen D.E., Lee I.-M., Schaff D.A., Harrison N.A., Chang C.J., Davis R.E., Kingsbury D.T. 1996. Genomic diversity and differentiation among phytoplasma strains in 16S rRNA groups I (aster yellows and related phytoplasmams) and III (X-disease and related phytoplasmas). Int. J. Syst. Bacteriol. 1: 64-75.

Kirkpatrick B., Smart C., Blomquist C., Guerra L., Harrison N., Ahrens U., Lorenz K.H., Schneider B., Seemüller E. 1994. Identification of MLO strain-specific primers obtained from 16/23S spacer sequences. Int. Org. Mycoplasmol. Lett. 3: 261-262.

Lorenz K.H, Schneider B., Ahrens U., Seemüller E., 1995. Detection of the apple proliferation and pear decline phytoplasmas by PCR amplification of ribosomal and nonribosomal DNA. Phytopathology 85: 771-776.

Posnette A. F., Chiykowski L. N. 1987. Strawberry green petal and similar diseases. In: Virus diseases of small fruits. R. H. Converse, ed. U.S. Dep. Agric. Handb. 631: 34-38.


pp. 133 - 136

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Efficacy of Euparen 50 WP and Euparen M 50 WG in the control of grey mould (Botrytis cinerea) and reduction of the population of two-spotted spider mite (Tetranychus urticae Koch) on strawberries Beata Meszka, Barbara H. Łabanowska, Anna Bielenin Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Pomologiczna 18, Poland Abstract: Grey mould (Botrytis cinerea) is one of the most important fungal diseases on strawberry in Poland. Usually 3-4 treatments are necessary for its control. Euparen 50 WP (dichlofluanid) is the most commonly used fungicide. The aim of the experiments was to compare the efficacy of Euparen 50 WP and the new formulation -Euparen M 50 WG (tolyfluanid) in control of grey mould of strawberries. The influence of dichlofluanid on development of the two-spotted spider mite (Tetranychus urticae Koch) population on strawberry was assessed, too. Both fungicides tested provided a good control of grey mould. Efficacy of dichlofluanid was similar to that obtained with procymidone, which is considered to be the best fungicide against grey mould. Euparen 50 WP and Euparen M applied 3 - 4 times against Botrytis cinerea reduced also two-spotted spider mite on plantations with a moderate population of the pest. Key words: grey mould, two-spotted spider mite, Tetranychus urticae, chemical control, dichlofluanid, tolyfluanid. Introduction Grey mould (Botrytis cinerea) is one of the most important fungal diseases of strawberry in Poland. It must be controlled every year - usually 3-4 treatments are necessary during the blooming time, depending on weather conditions, to control the disease. The following fungicides are recommended for control of grey mould: Euparen 50 WP (dichlofluanid), Sumilex 500 SC (procymidone), Thiram Granuflo 80 WG, Pomarsol Forte 80 WG (tiuram), Rovral 50 WP and Rovral Flo 255 SC (iprodione) and Mythos 300 SC (pyrimethanil). Euparen 50 WP (dichlofluanid) is used most commonly. It provides a good control of grey mould and also reduces leaf spot (Mycosphaerella fragariae) and powdery mildew (Sphaerotheca macularis). There are also reports that dichlofluanid influences population of two-spotted spider mite (Tetranychus urticae Koch) (Łabanowska and Bielenin, 1997). The aim of the experiments was to compare the efficacy of Euparen 50 WP and the new formulation - Euparen M 50 WG (tolyfluanid) in control of grey mould on strawberries. The influence of dichlofluanid on population of the two-spotted spider mite on strawberry was also assessed. Materials and methods The efficacy of fungicides in the control of grey mould was evaluated in 1998 on strawberry cv. Elkat in the Experimental Orchard in Skierniewice and in 1999 on cv. Senga Sengana at a private farm near Skierniewice. The strawberries were sprayed four times starting at the beginning of bloom and then every 5-7 days. A motor knapsack sprayer "Solo” was used and the dose was 600 l of liquid per 1 ha.

The evaluation of efficacy of fungicides in control of grey mould was made twice during the

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harvest on a sample of 400 ripe fruits taken randomly from each treatment. The diseased fruits were counted at harvest and after 24 h of storage at room temperature. The results presented in table 1 represent the sum of diseased fruits assessed at both times.

The influence of Euparen 50 WP and Euparen M 50 WG on two-spotted spider mite population was evaluated during 1997-1999 on plantations where Euparen 50 WP and Euparen M 50 WG were used to control the grey mould. The active stages of mites were counted 3-4 times during the growing season on a sample of 120 large leaves taken at random from each treatment. These mites were counted according to Henderson – McBurnie’s technique (Henderson and McBurnie, 1943). The results are presented in table 2. Results and discussion Grey mould control The severity of the infection by Botrytis cinerea strongly depends on weather conditions, mainly on temperature and humidity. In a very wet season 1999, with a lot of rain during blossom and harvest time the intensity of the disease was extremely high. On the untreated plots more than 50% of fruits were lost due to the grey mould (Tab. 1). Table 1. Efficacy of Euparen 50 WP and Euparen M 50 WG in the control of grey mould on

strawberries a) Elkat cv., Skierniewice, 1998

Percent of affected fruits at harvest and after 24 hrs storage at 200 C Fungicide

and rate per 1 ha Harvest: 10.VI

Harvest: 16.VI

Mean of two evaluations

Euparen 50 WP (dichloflanid), 5.0 kg 2.2 a 5.3 a 2.7 a Euparen M 50 WG (tolyfluanid), 5.0 kg 2.6 a 7.7 a 4.0 a Check (untreated) 2.2 a 10.4 a 8.3 b

Dates of treatment: 14,21 and 28 May b) Senga Sengana cv., Miedniewice, 1999

Percent of affected fruits at harvest and after 24 hrs of storage at 200 C Fungicide

and rate per 1 ha Harvest: 15.VI

Harvest: 21.VI

Mean of two harvests

Euparen 50 WP (dichloflanid) 5.0 kg 4.6 a 7.0 ab 5.8 ab Euparen M 50 WG (tolyfluanid) 5.0 kg 9.0 a 17.9 b 13.6 b Sumilex 500 SC (procymidon) 1.5 l 4.9 a 2.3 a 3.8 a Check (untreated) 67.7 b 81.3 c 73.5 c

Dates of treatment: 17, 21 and 31 May, 1 June. In a drier year 1998 only about 10 % of infected fruits were observed on control plots. Both

fungicides tested provided a good control of grey mould. In 1999, under a high pressure of

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disease, Euparen 50 WP was slightly more efficient than Euparen M 50 WG. Efficacy of dichlofluanid was similar to that obtained by procymidone, which is considered to be the best fungicide against grey mould. Because the resistance of Botrytis cinerea to dicarboximide fungicides has been developed on strawberry plantations (Beever at al. 1983, Dennis at al. 1979), both tested fungicides, dichlofluanid and tolyfluanid are very useful for rotation in control of grey mould. Influence of Euparen on the population two-spotted spider mite Euparen 50 WP used 3 times during the bloom of strawberry to control grey mould reduced also the population of two-spotted spider mite. The average number of mites per one leaf was lower on the treated plants than the economic threshold level (Tab. 2a). On the untreated plants there were 4 - 6.4 mites/leaf, indicating that population was slightly higher than the economic threshold.

In earlier experiments, Euparen M 50 WG used four times during the blossom time against the grey mould reduced the mite population in comparison with untreated plants but it was less effective than four treatments with Euparen 50 WP (Tab. 2b).

Table 2. Influence of Euparen 50 WP used in control of grey mould on the two-spotted spider

mite (Tetranychus urticae Koch.) population

a) Elkat cv., Skierniewice 1999 Number of mites per 1 leaf Fungicides and

active ingredients Dose

(kg/ha) Number of treatments June, 15 June, 30 July, 13

Euparen 50 WP (dichlofluanid) Check (untreated)

5,0 –

3 0.02 a

3.9 b

0.1 a

4.6 b

0.7 a

6.4 b

Date of treatments: 20 and 25 May and 1 June

b) Senga Sengana cv., Miedniewice 1997 Number of mites per 1 leaf Treatment Dose

(kg/ha) July, 17 August, 11 August, 25 Euparen 50 WP (dichlofluanid) Euparen M50 WG (tolyfluanid) Check (untreated)

5,0

5,0 –

0.03

0.9

1.9

0.1

0.6

2.1

0.7

0.9

1.6

Dates of treatments: 17, 21 and 27 of May 1 of June Conclusions 1. Euparen 50 WP and Euparen M 50 WG provided similar, good control of grey mould in the in

field experiments. The fungicides are useful in antiresistance program and they can be used in rotation with other groups of fungicide in control of grey mould.

2. Euparen 50 WP and Euparen M used for the control of grey mould reduce also the two-spotted

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spider mite population. Euparen applied 3-4 times against Botrytis cinerea reduced the Tetranychus urticae population quite well on the plantations with a moderate population of mites. One treatment with Euparen was not sufficient.

References Beever R.E., Brien H.M. 1983. A survey of resistance to the dicarboximide fungicides in Botrytis

cinerea. New Zealand J. Agric. Res. 26: 391-400. Dennis C., Davis R.P. 1979. Tolerance of Botrytis cinerea to iprodione and vinclozolin. Plant

Path. 28: 131-132. Henderson C.F., McBurnie H.F. 1943. Sampling technique for determining population of the

citrus red mite and its predators. USDA Circ. 671: 1-11. Łabanowska B.H., Bielenin A.1997. Euparen - fungicyd ograniczajocy populację przędziorków

na truskawce. Materiały Ogólnopol. Konf. Ochr. Rośl. Sad: 90.


pp. 137 - 139

137

Usefulness of Mospilan 20 SP in Integrated Pest Management of soft fruits Barbara H. Łabanowska, Dariusz Gajek, Edmund Niemczyk Research Institute of Pomology and Floriculture, Skierniewice, Poland Abstract: Mospilan 20 SP (acetamiprid) was tested to control some pests in soft fruits plantations during 1998-99 at the Research Institute of Pomology and Floriculture in Skierniewice (Poland). In 1999 the selectivity of the insecticide for Phytoseiid mites was also evaluated.

Mospilan 20 SP showed a good control of strawberry blossom weevil (Anthonomus rubi) on strawberry and raspberry, raspberry beetle (Byturus tomentosus) on raspberry, rose torthrix moth (Archips rosanus) and blackcurrant stem midge (Resseliella ribis) on blackcurrants. The chemical was selective to phytoseiid mites (Phytoseiidae) on blackcurrants. Key words: Acetamiprid, Anthonomus rubi, Byturus tomentosus, Archips rosanus, Resseliella ribis, Phytoseiidae, raspberry, strawberry, currant Introduction and methods Pests like weevils, worms and flies cause considerable damages on small fruit plantations in Poland (Łabanowska 1997a, 1997b). The chemical control of these pests is not easy, especially on plantations managed according to the integrated fruit production rules (IFP) (Łabanowska and Bielenin, 2000; Olszak et al., 2000). Therefore, we are looking for the selective insecticides to control the pests without any harm to the beneficial organisms. In orchards with IFP methods Mospilan 20 SP is a new, recommend insecticide. In recent years the chemical was tested in control of some pests on soft fruit plantations. The experiments were carried out in 1998-99 at the Research Institute of Pomology and Floriculture in Skierniewice. Mospilan was used to control the following pests: – strawberry blossom weevil (Anthonomus rubi Hbst.) on strawberry and raspberry, – raspberry beetle (Byturus tomentosus Deg.) on raspberry, – rose torthrix moth (Archips rosanus L.) and black currant stem midge (Resseliella ribis) on black currant. In 1999 selectivity of Mospilan 20 SP for phytoseiid mites on blackcurrants was also evaluated. Dose rate of the insecticide, dates of treatments and some selected results are shown on Table 1 and Figure 1. Results and discussion Efficacy of Mospilan 20 SP in pest control Mospilan 20 SP used once on strawberries just before blooming gave satisfactory control of strawberry blossom weevil (A. rubi) (Tab. 1). The results were similar to those obtained with standard insecticides such as fenitrothion (Sumithion 500 EC), etofenprox (Trebon 10 SC) and phosalone (Zolone 35 EC).

138

Table 1. The efficacy of some insecticides in control of strawberry blossom weevil (Anthonomus rubi Hbst.) on strawberry and raspberry plants and raspberry beetle (Byturus tomentosus Deg.) on raspberry

Skierniewice 1999 A. rubi*

damaged buds B. tomentosus**

damaged fruits (%) Term of harvest

Insecticides (active ingredient)

Dose a.i.

(g/ha) on strawberries

on raspberries I II III

Mospilan 20 SP (acetamiprid) Mospilan 20 WP (acetamiprid) Trebon 10 SC (etofenprox) Zolone 350 EC (phosalone) + Trebon 10 SC (etofenprox) Sumithion 500 EC (fenitrothion) Check (untreated)

25

40

90

875

90

1125 –

1.4

0.9

1.4 –

1.2

16.0

0.2 –

0.4

0.9 –

6.0

0.0 –

0.0

0.0 –

2.0

0.0 –

0.5

0.0 –

3.0

1.0 –

0.3

1.3 –

7.0

* Date of treatment on strawberry - May 10, 1999 ** Dates of treatments: before bloom (May 24), full bloom (June 7, 1999 - in the evening)

Figure 1. Occurrence of Phytoseiid mites on blackcurrants after treatment with Mospilan 20

SP - Skierniewice 1999 Mospilan 20 SP used twice on raspberries, before and at full bloom, showed good and satisfactory control of strawberry blossom weevil (A. rubi) and raspberry beetle (B. tomentosus) (Tab. 1). The results were similar to those obtained with standard insecticides -phosalone (Zolone 35 EC) and etofenprox (Trebon 10 SC).

139

Mospilan 20 SP used once just after blossom of blackcurrants against young larvae of the rose tortrix moth (A. rosanus) gave satisfactory control of the pest. The obtained results were similar to those obtained with fenitrothion (Sumithion 500 EC). Mospilan 20 SP used at the time of flight of the first and second generations of the black currant stem midge (R. ribis) gave satisfactory control of the pest. The results were similar to those obtained with a standard insecticides, e.g. etofenprox (Trebon 10 SC). Selectivity of Mospilan 20 SP to Phytoseiid mites on blackcurrants. Mospilan 20 SP at concentration 0.02% applied on blackcurrants showed selectivity to Phytoseiid mites (Fig. 1). No statistical difference in number of mites on treated and untreated bushes was observed at three terms after the insecticide application Conclusions 1. In strawberries, Mospilan 20 SP used at the dose rates 0.125 and 0.2 kg/ha just before

blossom, gave satisfactory control of strawberry blossom weevil (Anthonomus rubi). 2. In raspberries, Mospilan 20 SP used at the dose rate 0.125 kg/ha just before blossom and

during blossom gave a good control of strawberry blossom weevil (A. rubi) and raspberry beetle (Byturus tomentosus).

3. In black currants, Mospilan 20 SP used at the dose rates 0.125 and 0.2 kg/ha just after blossom, gave a good control of rose torthrix moth (Archips rosanus).

4. Mospilan 20 SP (0.2 kg/ha) gave a good control of blackcurrant stem midge (Resseliella ribis).

4. Mospilan 20 SP (0.02%) showed a selectivity to phytoseiid mites (Phytoseiidae) on blackcurrants.

5. After registration, Mospilan 20 SP should be useful in integrated pest management in soft fruit.

References Łabanowska B.H., 1997a. Control of the strawberry blossom weevil (Anthonomus rubi Hbst.)

on strawberry. J. Fruit Ornam. Plant Res. 5 (3-4): 157-162. Łabanowska B.H., 1997b. Dynamika składania jaj i efektywność zwalczania pryszczarka

porzeczkowca pędowego - Resseliella ribis (Marik.) (Diptera, Cecidomyiidae). Zesz. Nauk Inst. Sad. Kwiac. 4: 135-147.

Łabanowska B.H., Bielenin A., 2000. The standard and integrated strawberry production in Poland. IOBC/wprs Bulletin 23(7): 7-10.

Olszak R.W., Łabanowska B.H., Bielenin A., Gajek D., 2000. Prospects of developing integrated methods of small fruit production in Poland. IOBC/wprs Bulletin 23(7): 1-6.

140


pp. 141 - 143

141

Preliminary IPM program for blackcurrant crop for Poland E. Niemczyk, B. Łabanowska, D. Gajek Research Institute of Pomology and Floriculture, 96-100 Skierniewice, Poland The main aim of IPM of blackcurrants is effective control the two main pests: currant gall mite and spider mites using non chemical methods or selective insecticides. The blackcurrant gall mite (Cecidophyopsis ribis ) may be effectively controlled only with chemicals. The efficacy of natural enemies – predatory mites (Phytoseiidae) and a parasitoid (Tetrastichus eriophyes - Eulophidae) in controlling of blackcurrant gall mite is very low (Gajek et al. 2000). Therefore, the plantations of blackcurrants should be established only with healthy plants, free from most important pests and diseases.

Two-spotted spider mite (Tetranychus urticae) on blackcurrants may be kept on a very low level by predatory mites (Phytoseiidae) occurring in environment and inhabiting naturally the plantations (Niemczyk et al. 1996 ). Amblyseius andersoni, A. bryophilus and Euseius finlandicus are the most common phytoseiids naturally occurring on blackcurrants in Poland (Niemczyk 1994, Niemczyk et al. 1996; Kropczynska et al. 1994, Jaworski 2000). The other phytoseiid mites (Amblyseius californicus, Metaseiulus occidentalis, Typhlodromus pyri and Neoseius fallacis) obtainable on the marked and released on plantations may also suppress spider mite populations on blackcurrants. Therefore, only insecticides selective to phytoseiids should be used for pest control on blackcurrant plantations. Endosulfan applied even three times per season did not kill the predatory mites A. andersoni and T. pyri. At the same time it controlled aphids on blackcurrants (Gajek et al. 2000). It was also found that acetamiprid (Mospilan), an effective broad-spectrum insecticide, was also selective to the phytoseiids on blackcurrants (Łabanowska et al. 2000).

The presented in the table IPM program should be treated as the preliminary one and has to be improved. Threshold levels should be elaborated for all the pests listed in the table. Also, the effectiveness of insecticides selective to black currant stem midge (Resseliella ribis) and currant clarwing moth (Synathedon tipuliformis) should be examined.

The fungicides toxic to phytoseiids should be avoided on blackcurrant crops cultivated according to IPM rules. References Gajek D., Niemczyk E., Sekrecka M. (2000). Effectiveness of different control methods of black

currant gall mite and their influence on populations of phytoseiid mites and two-spotted spider mite. IOBC/wprs Bull. 23(7): 47-52.

Jaworski S. (2000). Occurrence of phytoseiid mites (Acari: Phytoseiidae) on blackcurrant plantations and in surrounding vegetation in southern Poland. IOBC/wprs Bull. 23(7): 57-62.

Kropczynska D., Cichocka E., Czajkowska B. 1994. Biologiczne podstawy integrowanego zwalczania roztoczy i mszyc na jabłoniach i porzeczkach. Sprawozdanie końcowe Projektu Badawczego KBN nr 5065491.

Łabanowska B., Gajek D., Niemczyk E. (2000). Usefulness of Mospilan 20 SP in integrated pest management of soft fruits. IOBC/wprs Bull. 23(7): 137-140.

142

Niemczyk, E. 1994. Występowanie efektywność i wykorzystanie drapieżnych roztoczy (Phytoseiidae) do zwalcznia przędziorka chmielowca (Tetranychus urticae) na czarnych porzeczkach. Sprawozdanie końcowe Projektu Badawczego KBN nr. 5207 9203.Res. Inst. of Pomology and Floriculture, Skierniewice.

Niemczyk E., Sekrecka M., Kumor I. 1996. The occurrence, species composition and effectiveness of predatory mites (Phytoseiidae) to two spotted mites (Tetranychus urticae Koch) appearing on black currant. IOBC/WPRS Bull. 19(4): 374-376.

Remark and explanations to the table on the opposite page 143 Remark In order to maintain the phytoseiids on black currants only selective fungicides have to be used. These are: – for control of currant blister rust (Cronartium ribicola):

dithianon (Delan), triadimefon (Bayleton), flusilazol (Punch), bupirimate (Nimrod) – for control of American gooseberry mildew (Sphaerotheca mors uvae):

triadimefon (Bayleton), bupirimate (Nimrod), fenarimol (Rubigan), flusilazol (Punch), difenoconazol (Score)

– for control of anthracnose of currants (Drepanopeziza ribis) and septoria leaf spot (Mycosphaerella ribis): dithianon (Delan), triadimefon (Bayleton), flusilazol (Punch), difenoconazol (Score)

Explanations 1. overwinters in the field conditions, obtainable on the marked 2. does not overwinter in Poland, obtainable on the marked 3. during time of treatment predatory mites overwinter in shelters. 4. not registered for black currant.

Preliminary IPM program of black currant crop for Poland

Pest species Necessity of control on standard crop

Control measures on IFP crop Threshold level Detection of pest and timing of sprayings

Black currant gall mite (Cecidophyopsis ribis)

2-3 treatments each year on each plantation

at least 1 treatment with endosulfan (Thiodan, Thionex) and removing of infested buds from established of plantation

no infested buds visual inspection in dormant season - usually at early spring

Two spotted spider mite (Tetranychus urticae)

1-2 treatments on majority of plantations

a) Introduction of predatory mites: Typhlodromus pyri 1, Neoseiulus fallacis 1, Metaseiulus occidentalis 2, Amblyseius californicus 2

b) Maintaining native naturally occurring preda-tory mites: Amblyseius andersoni, A. bryophilus, A. umbraticus, Euseius finlandicus, T. pyri.

c) Spraying with hexytiazox (Nissorun)

1 mite/leaf before flowering 1-2 mites/leaf after blooming 3-4 mites/leaf after harvest

counting mites on the leaves: 200 leaves collected from 50 bushes (4 leaves per bush)

Aphids Aphis schneideri, Hyperomyzus lactucae, Cryptomyzus ribis

On majority of plantations in some years

acetamiprid (Mospilan) 4 pirimicarb (Pirimor) endosulfan used against gall mite controls also aphids

no established visual inspection of plantations

Currant shoot borer (Incurvania capitella)

On majority of plantations in some years

fenitrothion (Sumithion, Owadofos) 3 deltamethrine (Decis) 3

no established examination of plantations during bud burst or a little later

Black currant stem midge (Resseliella ribis)

On some plantations in some years

acetamiprid (Mospilan) 4 phosalone (Zolone)

no established

1. examination of one-year-old canes during winter time

2. cutting the skin of youngest canes where females lay eggs

Currant clarwing moth (Synathedon tipuliformis)

On some plantations in some years

Cutting shoots during winter or early spring phosalone (Zolone) no established

Pheromone traps

144


pp. 145 - 149

145

Storage of soft fruits Werner Ollig1, Helmut Schirmer2 and Erich Jörg3 1 State Institute for Education and Research in Agriculture, Breitenweg 71, D-67435 Neustadt/Wstr. 2 Instit. of Chemistry and Biology, Fed. Res. Centre of Nutrition, Engesserstr.20, D-67131 Karlsruhe 3 State Institute for Agronomy and Crop Protection, Essenheimerstr. 144, D-55128 Mainz Abstract: The storage of soft fruits is still in its infancy. An overview is given on the possibilities and conditions to store soft fruits in order to steer the market supply. Especially for gooseberries and red currants a long-term storage is possible. By applying appropriate temperature-CO2 content regimes fungal storage rots can be controlled sufficiently. Keywords: soft fruit, gooseberry, red currant, storage, fungal storage rots Introduction During the last five years the demand for fresh fruits of several soft fruit crops has increased considerably. On the other hand the supply of the fresh market with soft fruits is characterised by periods with oversupply as well as shortage on the availability of the fruits. And in addition it is not possible to supply the customers with fresh fruits of a certain variety which is well introduced in the market over a longer period. From pome fruit production it is known that CA-storage and ULO-storage may be applied successfully to store the fruits for a longer period while maintaining a high quality standard. So, it was tested if these methods can be employed for the storage of soft fruits in order to achieve: – a prolongation of the supply period of certain crops or cultivars; – a steering of market (avoid shortage or oversupply); – a sales promotion by developing new marketing lines (e.g. direct supply of gastronomy). Special attention was directed to the situation and storage facilities of self marketers who deal with smaller piles and quantities of less than a ton per crop. Prerequisites for the storage of soft fruits Not all harvested soft fruits are appropriate for a storage and not all storage facilities may be used for the CA-/ULO- storage of soft fruits. The prerequisites that have to be fulfilled to guarantee a successful storage are as follows (Ollig, 1998; Schirmer & Tauscher, 1998; Schirmer et al., 1997): • appropriate and robust cultivars (e.g. Elsanta for strawberries or Roodneus /Rovada for red

currants); • healthy fruits (especially free of fungal diseases); • dry fruits (Dierend et al., 1999); • early harvesting (after ripening in the storage facility); • avoidance of condensed water; • temperature regimes and CO2 contents must be adjustable to degree of ripeness and length

of intended storage period. Results

146

Trials were carried out for gooseberries and red currants to assess the influence of storage conditions on the weight losses, development of fruit rots and the marketability of the stored fruit. Gooseberries Table 1 shows the results for 1996 and 1997 trials. They may be summarised as follows. Gooseberries stored in normal air (at 1°C) were not marketable after the storage period of five weeks, whereas fruits from the other treatments could be marketed. By CO2 -storage the weight losses could be reduced considerably. Best results were obtained with a CO2 -content of 15 %. In addition this treatment gave the best results in the suppression of fungal diseases occurring during the storage period. Table 1. Gooseberries – results of storage under different conditions (cv. Achilles)

Weight losses (%)

Fruits with fungal diseases

(%) Treatments

after 5 weeks CA storage + 1 additional week

1996

after 8 weeks CA-storage

1997

after 5 weeks CA-storage 1997

Normal air (untreated) 10,8 14,0 67 5 % CO2 / 2 % O2 5,0 4,5 30 5 % CO2 5,1 9,0 33 15 % CO2 4,6 7,5 0 25 % CO2 4,9 10,0 0

A reduction in the O2 -content did not result in an improvement concerning the weight losses and disease control. Maximum storage period at 1°C and in normal air is three weeks. Anyway, after the fruits are taken out of the storage facilities they should be marketed within three to four days. Afterwards the sensoric quality decreases dramatically. Red currants With red currants comparable results have been obtained. CO2 -storage reduced weight losses up to 80 % (Table 2). Best results gave the CO2 -contents above 10 %. Only single berries had to be sorted out. In the „untreated plot“ Botrytis cinerea showed up whereas in a CO2 -content of above 10 % no mycelium could be observed. After removal of the fruits from the store is was possible to store the fruits for four more days in normal air and at 17°C without detrimental effects on quality. Trials on the storage of other soft fruit crops (Dierend et al., 1999; Quast 1999 a, b) gave similar results. This indicates that some soft fruit crops may be stored for longer periods up to 10-14 weeks depending on the stability of the fruits. Particular post-harvest treatments are not

147

necessary and will not be appreciated by the customers. With the storage under CA with higher CO2 -contents a sufficient suppression of fungal storage rots can be achieved. Table 2. Red currants – results of storage under different conditions (cv. Rovada)

Treatments Weight losses (%)

Normal air (untreated) 4,6 5 % CO2 0,9 10 % CO2 0,5 15 % CO2 0,7 20 % CO2 0,5

Recommendations For horticultural practice the following recommendations concerning the storage equipment (Table 3) and the storage conditions (Table 4) may be given. Table 3. Calculations for the storage of soft fruits under plastic cover

Costs DM/kg fruit

Storage methods Annual costsDM

Total annual costs for 1 pile

DM 1 pile /year

3 piles /year

Method 1 – storage cell purchased – fittings/instruments purchased – C02 + N2 from bottles of gas

1041.00 1141.00 3.80 1.26

Method 2 – storage cell purchased – fittings/instruments available – C02 + N2 from bottles of gas

405.00 505.00 1.68 0.56

Method 3 – storage cell self– made – fittings/instruments purchased – C02 + N2 from bottles of gas

816.00 916.00 3.27 0.98

Method 4 – storage cell self– made – fittings/instruments available – C02 + N2 from bottles of gas

180.00 280.00 0.93 0.31

Method 5 – storage cell self– made – fittings/instruments available – dry ice

180.00 211.00 0.70 0.23

148

With costs of less than 0.30 DM/kg it is possible especially for self-marketers to store piles of soft fruit assumed that three piles/year (different crops) are to be stored In general an increased CO2 -content prolongs the storage period. In the case of gooseberries a storage of 7 weeks is possible. For black currants no recommendation for the use of CO2 can be given due to the lack of trial results. For red currants the reduction in O2 -content (ULO) gives a considerable improvement of the storage results. The same holds for blueberries where the normal storage period of 2-3 weeks can be doubled. Problematic is the situation for raspberries and strawberries. Even by applying CA- and ULO- technology it is not possible to store the fruits longer than 2-3 days resp. 1 week. Table 4. Storage conditions for various soft fruit crops

Crop /Cultivar

Storage system Temp. °C

CO2 %

O2 %

Length of storage period

Red currants CA (CO2 only) 1 18 - 20 15 4-5 weeks /Rotet ULO 0 18 - 20 2 8-10 weeks

/Rondom, Rovada ULO 0 18 - 20 2 10-12 weeks /Augustus, Cassa

Roodneus, Blanka ULO 0 18 - 20 2 12-14 weeks

/All cultivars Cold storage (mechanically)

0-1 2-3 weeks

Other Crops

Raspberries CA 1-2 18-25 15 2-3 days Blueberries Cold storage

(mechanically) 0-1 5-10 2-3 weeks

ULO 1 10-15 10-15 4-5 weeks Gooseberries Cold storage

(mechanically) 0-1 2-3 weeks

CA (CO2 only) 1 15 15 5-7 weeks Black currants Cold storage

(mechanically) 0-1 1-2 weeks

Strawberries Cold storage (mechanically)

0-1 3-5 days

ULO 1-5 15 1.5 < 1 week /Elsanta ULO 0-1 18-20 2-3 7-10 days

References Dierend, W., H. Pribyl & R. Faby (1999): Einsatz von CO2 bei Himbeeren zur Verbesserung

der Haltbarkeit. Obstbau 5/99: 252-254. Ollig, W. (1998): CA-Lagerung von Beerenobst unter Praxisbedingungen. Obstbau 6/98: 314-

316. Quast, P. (1999 a): Die Empfindlichkeit von Früchten verschiedener Beerenobstarten gegen-

über höheren CO2 -Gehalten bei der CA-Lagerung. Mitt. OVR 54: 204-212.

149

Quast, P. (1999 b): Die mehrwöchige CA-Lagerung von Kirschen und Kulturheidelbeeren mit höheren CO2 -Gehalten. Mitt. OVR 54: 234-238.

Schirmer, H. & B. Tauscher (1998): Rote Johannisbeeren – Einfluß von CA-Lagerungen auf die Haltbarkeit und Qualität. Obstbau 6/98: 317-319.

Schirmer, H., B. Tauscher & W. Ollig (1997): Lagerung von Stachelbeeren. Obstbau 8/97: 402-404.

150


pp. 151 - 153

151

Pesticide residues in soft fruits: strawberries, currants and raspberries (Monitoring 1997-98) Anna Nowacka Institute of Plant Protection, Department of Pesticide Residues Research, Miczurina 20, 60-318 Poznań, Poland Abstract: The research was carried out in 1997-98 and included the determination of 19 active ingredients in 590 samples of soft fruits: strawberries (450), currants (100) and raspberries (40). Fifteen of the 19 analysed compounds were found in 205 samples. 65.3% of samples were without pesticide residues, 34.2% of samples contained residues below Polish maximum residue levels (MRLs). Violations of MRLs were found in 0.5% of samples. Key words: pesticide residues, fruits, strawberries, currants, raspberries Introduction National Monitoring System for pesticide residues has been established in 1971 as a result of the co-operation agreement between the Polish government and the FAO/UNDP organisation. Since the 70’s fresh fruits, vegetables and cereals have been checked for pesticide residues. An average of 2500 samples is analysed every year.

In 1997-98 19 pesticides were determined in 590 domestic samples of soft fruits. Materials and method 450 strawberry samples, 100 currant samples and 40 raspberry samples were collected. randomly from production sites in the whole country by the trained staff of the country Plant Protection Inspectorates. Samples were analysed by multi-residue methods based on acetone extraction, partitioning with methylene chloride and SPE (solid phase extraction) cleanup on an amino or silica gel mini-column. The determination of the pesticide residues was performed by GC/ECD/NPD and HPLC/UVD. Positive results were confirmed by GC/MSD or HPLC/PDA technique. The spectrophotometric method was used for the determination of the sum of dithiocarbamates. The quality control included daily check of the instrument sensitivity and recovery checks. Results and discussion 15 of the 19 pesticides analysed were found in 34.7% of samples. The residues of dichlofluanid, vinclozolin, procymidone and dithiocarbamates were the most frequently detected. The frequency of pesticide residue appearance was the highest in raspberries (55%), medium in strawberries (35.8%) and the lowest in currants (23%).

Number of samples containing a particular pesticide, the average content and the range of residues found in individual fruit are shown in table 1.

152

Table 1. Pesticide residues in strawberries, currants and raspberries (Monitoring 97-98) Fruit/Number of samples analysed

Pesticide Number of

samples with

pesticide residues

Average content

mg/kg

Range of

residues found

mg/kg

Number of

samples with

residues > MRL1

MRL1

mg/kg

Strawberries / 450 dichlofluanid 88 0,30 0,01 – 8,00 1 5 endosulfan 1 0,42 0 0,5 iprodione 7 0,18 0,02 – 0,80 0 10 lenacyl2 0 0 0,1 procymidone 32 0,25 0,05 – 1,07 0 5 vinclozolin 67 0,06 0,01 – 0,32 0 5

Currants / 100 dichlofluanid 7 0,12 0,02 – 0,20 0 5 dithiocarbamates3 12 1,24 0,10 – 2,86 2 2 endosulfan 9 0,06 0,01 – 0,11 0 0,5 fenarimol 1 0,10 0 1 flusilazole 1 0,18 0 0,2 MBC 0 0 1 procymidone 1 0,01 0 5 vinclozolin 0 0 5

Raspberries / 40 alphamethrin 4 0,02 0,01 – 0,03 0 0,05 bifenthrin 0 0 0,1 deltamethrin 2 0,02 0,02 – 0,02 0 0,2 dichlofluanid 12 0,19 0,02 – 0,80 0 5 dithiocarbamates3 3 0,10 0,10 – 0,10 0 2 fenitrotion 0 0 0,5 iprodione 2 0,16 0,11 – 0,21 0 10 phosalone 0 0 2 procymidone 8 0,22 0,03 – 0,52 0 5 vinclozolin 3 0,04 0,01 – 0,08 0 5 1) Polish maximum residue levels (MRLs) 2) 394 samples were analysed 3) Residues of maneb, mancozeb, metiram, zineb, thiram determined as CS2

The percentage distribution of pesticide residues in particular fruit is shown in Figure 1. Most samples with residues (71.2%) contained one active ingredient, but in some the

residues of two (24.4%) or three (4.4%) compounds were found. The residue levels were rather low. Of the fruit samples containing pesticide residues,

residue level was lower than 20% of MRLs in 94% samples of strawberries, 90.5% samples of raspberries and 84.5 % samples of currants.

Violations of MRLs were found in two samples of currants containing the residues of dithiocarbamates and in one sample of strawberries with residue of dichlofluanid.

The percent of all fruit samples with and without pesticide residues is shown in Figure 2.

153

Figure 1. Summary of results for individual fruit (97-98)

Figure 2. Summary of results for all fruit samples (97-98) Conclusions 1. No residues were found in 385 samples (65.3%) 2. Only in 3 samples (0.5 %) residues level exceeded MRLs 3. In majority of samples residues level was lower than 20% of MRLs 4. Currants accounted for most exceedings.

0,2

35,6

64,2

2

21

77

0

5545

0

20

40

60

80

100

% o

f sam

ples

strawberries currants raspberries

samples with residues > MRLs samples with residues < MRLs sample without residues

samples with residues < MRLs

34,2%

samples with residues > MRLs

0,5%samples without

residues65,3%

154


pp. 155 - 158

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Consumer’s acceptance of soft fruits from Integrated Production Krzysztof Zmarlicki Research Institute of Pomology and Floriculture, Economics Laboratory 96-100 Skierniewice, Poland Abstract The main aim of this study is to show the potential consumer’s acceptance of soft fruits from integrated production on the Polish fruit market. The market research was based on the interviews of fruit buyers. Key words: integrated production, market research, consumer’s acceptance, consumer surveys Introduction In some countries around the world like for example in Germany and in Canada fruit growers are looking more often for consumers who rate environmental stewardship as a major factor in their small fruit purchasing decisions. Surveys of consumer’s preferences conducted in developed countries during past few years show that buyers are going for the "green". Unlike trends for many specialty food items, the demand for such produce raised with environment directed practice is a mainstream, not a niche market, especially among young, educated middle and upper class people.

The market research in Poland emphasizes that there is a strong trend toward more healthful food. It is very common nowadays that consumers are looking for food described as low sugar, low calories, low salt, no cholesterol as well as no artificial additives. This was absolutely unheard of just about 12 years ago on the very poor Polish food market. There is a shortage of market research concerning Polish consumer’s aptitudes towards small fruits from integrated production. For that reason the main aim of this study was to show the basic consumers point of view about the soft fruits from the integrated production. Materials and methods The study of consumer acceptance was based on the oral interviews of fresh fruits buyers. A structured response questionnaire to describe acceptance of small fruits from integrated production among consumers on the market was developed and tested. Interviewers intercepted customers who stopped at a fruit display and bought some strawberries or raspberries. The survey was carried out in June and July of 1999 in the area of Skierniewice /n =142/ and Warsaw downtown /n =79/. The following types of buying places were considered: specialist fruit and vegetable stores, supermarkets and market places.

The questionnaire consisted of two types of questions. First group of questions related to integrated production: which fruits I would rather buy - those from integrated production or produced traditionally, knowledge of meaning and principles of integrated production and willingness to pay 25% more for small fruits from integrated production. The second group consisted of socioeconomic questions like age, education level, sex, income, marital status and family size and are similar to other Polish fruits consumer’s surveys (Zmarlicki 1998).

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• Age – consumers were divided into five equal groups according to the general population structure of Poles above 18 years old. First segment consisted of consumers aged from 18 to 28 years, second from 29 to 37, third from 38 to 47, fourth from 48 to 62 and to the last one belonged consumers 63 years old and older;

• Education levels – grammar school, high school, university; • Sex – male, female; • Income – surveyed customers were grouped into four monthly income levels according to

State Statistical Office (GUS 1998) • Marital status and family size – single, married, couple with one child, couple with two

children, families with five and more members The questionnaire replies were computed through the Statistical Package for Social Sciences

(SPSS) version 8.0 for Win 95. Results Consumers preferred much more frequently to buy small fruits from the integrated production /n = 177/ than traditionally produced ones /n = 19/, whereas no preference for the type of production was declared by 25 surveyed (Fig. 1). The sex, education level, income per capita in the household and the marital status of customers did not have a significant influence on the responses to this question.

Most of the surveyed customers /n=203/ did not know what integrated production of strawberries and raspberries means (Fig. 2). Similarly as in the first question, sex, education, income per capita in the household and the marital status of the customers did not have significant influence on the responses to this question.

Of 221 customers surveyed as many as 149 were willing to pay 25% more for the small fruit from integrated production even though most of them did not know what for they would be paying for. There were only 11 consumers from the first age group (18 - 28 years old) who knew the integrated production in this segment (Fig. 3). Only the income level had the impact on customer’s willingness to pay more, but not education, age or other socioeconomic factors. Conclusions 1. Surveyed customers prefer to buy fruits from integrated production. Probably they associate

the word ”integrated” with better quality of fruits. 2. Producers that produce soft fruits by the integrated method should improve marketing of

their products. Especially, some information about IFP on the market is desirable since most of the consumers do not know what integrated fruit production means.

3. The demand for more expensive fruits on the market should have an impact on producers to shift to production of better quality fruits. It is expected that in the near future term “Fruit from integrated production” will be more widely understood as fruits of the highest quality.

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Figure 1. From which source I would rather buy small fruits?

Figure 2. Understanding of integrated fruits production in age segments

Fruits from Integrated Production Fruits from non Integrated Production No preferences

% of surveys who did not hear about Integrated Production

% of surveys familiar with Integrated Production

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Figure 3. Surveys who would pay more for small fruits from Integrated Production References Rocznik Statystyczny GUS Warszawa 1998 Zmarlicki K. 1998. The consumer preferences for plums in the central part of Poland. Acta

Horticult. 478:

No acceptance to pay more for fruits from Integrated Production Acceptance to pay 25% more for fruits from Integrated Production


pp. 159 - 165

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Guidelines for the Integrated Production of Soft Fruits - IOBC - Technical Guideline III Erich Jörg 1) & Jerry V. Cross 2) 1) Landesanstalt für Pflanzenbau und Pflanzenschutz, Essenheimerstr. 144, D-55128 Mainz,

Germany 2) Horticultural Research International East Malling, East Malling, West Malling, Kent,

ME19 6BJ, UK A short overview on IOBC guideline work for IP IOBC – guideline work for Integrated Production (IP) started in 1977 with the „Declaration of Ovrannaz“ (Tab. 1). This document may be considered the forerunner of the Technical Guidelines (TG) for IP. A commission named „Commission pour la valorisation de la Production Intégrée“ was founded in 1978 being responsible for the elaboration of IP – guidelines (Baggiolini, 1998). However, it was the IOBC – Working Group „Integrated Plant Protection in Orchards“ that intensively discussed a TG for IP of pome fruits. After several meetings „General Principles, Guidelines and Standards for Integrated Production of Pome Fruits in Europe“ were published in 1991 as a provisional working document. Meanwhile the reactivated IOBC – Commission „Integrated Production – Guidelines and Endorsement“ had elaborated a comprehensive document defining the IP – Principles and Technical Guidelines I and II (published in 1993) which form the basis for crop specific IP – guidelines (TG III). In the following years the fruitful work on IP – guidelines of the IOBC – Working Groups resulted in the publication of TG III for pome fruits (revision of the 1991 document), viticulture (1996), stone fruits (1997) and arable crops (1997). In 1999 a revised and improved version of the viticultural IP – guideline was published. In the same year a TG III for soft fruit IP was finalised that shall be published in 2000. The future IP – guideline work of IOBC aims at the elaboration of TG III for citrus crops, olives and field vegetable production in the coming four years.

From 1996 on IOBC – Commission strongly aided the Working Groups in the elaboration of TGs III. The main task was and still is to guarantee the congruence of TG III with the basic documents (IP-Principles, TG I and II). In addition IOBC – Commission worked out evaluation schemes (Tab. 1) to check if IP – guidelines of farmers` associations fulfill the requirements of IOBC – TGs I - III and if these IP – organisations may be recognised by IOBC as meeting its IP - standards. To include the permanent progress in IP it was decided to revise the TGs in five year intervals. For the basic documents this has been done in 1999. The next IP - guidelines which need revision is TG III for pome fruits. Elaboration of TG III for Soft Fruit IP The elaboration of TG III for IP of soft fruits follwed a procedure proposed by IOBC – Commission. A panel of a few experts assembled at Vienna in late 1996 to discuss the main problems in IP of soft fruits (Tab. 2). Agronomists as well as crop protection scientists were present. Based on the progress made during the expert panel German colleagues were asked to prepare a TG III – draft. In 1997 the draft was elaborated and discussed on the First IOBC –

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Workshop on Soft Fruits held at Vienna in October 1997. Here a version was agreed upon and submitted to IOBC – Commission for inspection. Due to general problems which concern IP of all crops the agreement on the version of TG III for soft fruit IP was postponed until an IOBC – Council`s decision. After the Council`s decision in 1998 the authors were asked to finalise the guideline draft. IOBC – Commission gave the agreement in April 1999. In the following months the translation of the original English version into six further European languages (French, German, Spanish, Italian, Polish and Hungarian) was done. In December 1999 the TG III for IP of soft fruits was submitted for printing as IOBC – Bulletin. The evaluation scheme is in preparation. Table 1. IOBC - Guideline Work for IP (IP-Guidelines and Evaluation Schemes)

Year Guideline Evaluation Scheme

1977 „Declaration of Ovrannaz“ (Altner, Baggiolini, Celli, Schneider, Steiner)

1991 IP of Pome Fruits (provisional working document) (IOBC-Bull. 14(3), Dickler & Schäfermeyer)

1993 IP-Principles and Technical Guidelines (TG I, II) (IOBC-Bull. 16(1), 18(1.1,1.2) El-Titi, Boller & Gendrier)

1996/7

1994 IP of Pome Fruits (TG III) (IOBC-Bull. 17(9), Cross & Dickler)

1996/7

1996 IP for Viticulture (TG III) (IOBC-Bull. 19(10), Schmid)

1997 IP of Stone Fruits (TG III) (IOBC-Bull. 20(3), Cross, Malavolta & Jörg)

1997

1997 IP of Arable Crops (TG III) (IOBC-Bull. 20(5), Boller, Malavolta & Jörg)

1998

1999 IP for Viticulture (TG III) 2nd ed. (IOBC-Bull. 22(8), Malavolta & Boller)

1999

1999 IP-Principles and Technical Guidelines (TG I, II) 2nd ed. (IOBC-Bull. 22(4) Boller et al.)

1999

2000 IP of Soft Fruits (TG III) (IOBC-Bull. 23(5), Jörg & Cross)

2000

2000 - 2001 IP of Pome Fruits (TG III) 2nd Ed.

2001

2001 - 2002 IP of Citrus (TG III)

2002

2001 - 2002 IP of Olives (TG III)

2002

2002 - 2003 IP of Field Vegetables (TG III)

2003

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Table 2. Elaboration of IOBC – TG III for Integrated Production of Soft Fruits – History

1996 Oct.

Expert Panel (Berrie, Gajek, Jörg, Lieten, Polesny, Steffek)

1997 Preparation of a Draft Guideline (Faby, Fried, Galli, Gärtner, Harzer, Jörg)

1997 (October 7.-10.)

First IOBC-Workshop on Soft Fruits

1998 Discussions on General Topics IOBC – Council`s Decision

1998/9 Preparation of the Final Draft (EJ & JVC)

1999 (April 17.)

Final Agreement by IOBC – Commission

1999 Finalisation of the Translations (En, Fr, Ge, Sp, Pol, Hun, It)

1999 (December)

IOBC – Bulletin: Final Draft submitted for printing

2000

Evaluation Scheme

General Problems As mentioned above general problems firstly had to be solved to finish this TG III. The points under discussions were: - Sustainability - Use of genetically modified organisms (GMOs) GMOs are discussed controversely in society. In fruit production 14 genetically modified cultivars were available at least for research purposes in 1998 (Tab. 3). Mainly they were resistant to noxious agents or had a modified metabolism (Tab. 3 and 4). The use of such cultivars could reduce the pesticide or fungicide input considerably, which is one of the main aims of IP. On the other hand some security problems are not completely cleared up. Weighing up pros and cons IOBC – Council decided to take a case – specific decision in the permission of GMOs in Integrated Production. Table 3. Transgenic Fruit Cultivars in Europe (May 1998)

Crop Total Nr.

Metabolism Insect resistance

Virus resistance

Fungal dis. resistance

Apple 2 0 1 0 1 Plum 1 0 0 1 0 Cherry 3 3 0 0 0 Strawberry 3 1 1 0 1 Kiwi 3 2 0 0 1 Olives 2 1 0 0 1

Ref.: BBA, from Jehle (1998)

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Table 4. Important Properties of Transgenic Fruit Cultivars (1987-1997)

Crop Transgenic Properties

Inherited Properties /Resistance to

Apple B.t.-Toxin Cecropin B Attacin E Lysocyme

Lepidoptera Fire Blight (Erwinia amylovora)

Plum PPV Sharka Virus Strawberry Glucanase,

Chitinase, Polygalacturonase Sam-Transferase

Botrytis, Sclerotinia, Verticillium, Colletotrichum, Phytophthora, Pythium Fruit ripening

Cranberry B.t. Toxin Lepidoptera Papaya PRV Papaya Ringspot Virus

Ref.: BBA, from Jehle (1998) Integrated Production more and more is linked to sustainable agriculture or sustainable land use. In the future EU – incentives are coupled with land use systems that fullfil the requirements of sustainability. In several agro-environmental programmes based on EU – Regulation 2078/92 IP is considered to be such a sustainable system. The question arose if high-input systems (e.g. heated glasshouses, non-soil systems), which are quite common for some soft fruit crops, are sustainable. Allen et al. (1991), Meadows et al. (1992) and Abelson (1995) set up the following relevant principles for sustainability in general (among others): • raw materials and energy input from regenerative sources • maintenance and protection of regenerative ressources • all production processes are cycles • system stabilising diversity of processes and products • adoption of education models to the changes in paradigm Specifically for agricultural production the following requirements must be fullfilled to consider a production system a sustainable one: • efficient use of ressources • minimising off-farm input • replacement of non-renewable ressources by regenerative ones • precaution principle as the basis of production • maintenance of ecosystems and biodiversity

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• maintenance and increase of soil fertility • prices reflect „ecological truth“ • pollution with respect to absorptive capacity of the ecosystems Judging the multitude of production systems for soft fruit according to the criteria listed up above, IP was restricted as follows.

IOBC - Technical Guidelines III are for soft fruit crops grown in the soil in the open or under non-heated protection only.

Hors soil – systems and heated glasshouse – production are not in congruence with sustainability. However, they also have some advantages in comparison to soil bound systems in the open field. E.g., these systems are very appropriate for the application of biological control measures. So further discussion is needed to improve the valuation of the various systems. Structure and Content of TG III for Integrated Production of Soft Fruits TG III for soft fruit IP (Tab. 6) is structured analogous to TG III for stone fruit IP. Chapters 1 – 3, 5 – 9 and 11 – 14 only needed minor modifications to adapt them to soft fruit crops. Chapters 4 and 10 have been modified considerably. Because of the great importance of phytosanitary measures for soft fruit crops requirements and recommendations concerning the choice of the production site, crop rotation, cultivation and planting material are set up in Chapter 4 (Tab. 5). In addition high priority is given to cultivars which are resistant to pest and/or diseases. Table 5. TG III for Integrated Production of Soft Fruits –

Chapter 4: Site, Cultivar, Planting Material and Planting System for new Soft Fruit Plantations

Cultivar choice – high priority for resistant cultivars

Site – raspberry⇒not twice on the same site – preference for new sites for straw/raspberry – avoid soil with perennial weeds(rec.) – no soils with Phytopht. for raspberry

Planting material – certified – additional testing recommended – growers´ own pl.mat.⇒additional. testing – pesticide contamin.⇒biological control !

Cultivation aspects – ridge cultivation recomm. for straw/raspberry – avoid „Verticillium crops“ before strawberry – crop rotation recommendations strawberry – maximum life span 3 yrs. for strawberry

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Table 6. Structure of TG III for Integrated Production of Soft Fruits

No. Chapter

1 Definition of Integrated Production of Soft Fruits 2 Professionally Trained and Safety Conscious Grower 3 Conserving the Orchard Environment 4 Site, Cultivar, Planting Material and Planting System for New Soft Fruit

Plantations 5 Soil Management and Plant Nutrition 6 Alleyways and Weed-free Strips 7 Irrigation 8 Horticultural Management 9 Fruit Management 10 Integrated Plant Protection 10.1 Additional Requirements on Strawberry 10.2 Additional Requirements on Cane Fruits 10.3 Additional Requirements on Bush Fruits 11 Efficient and Safe Spray Application Methods 12 Harvesting, Post-harvest Handling and Fruit Quality 13 Post-harvest Chemical Treatments 14 Mode of Application,Controls,Certification and Labelling

In Chapter 10 of TG III for stone fruit IP two groups of crops have been differentiated („southern“ crops, e.g. peaches, apricots, and „northern crops“, e.g. plums and cherries) because of striking differences in the crop protection systems. Concerning soft fruits three groups of crops have been distinguished: arable crops (e.g. strawberries), cane fruits and bush fruit (Tab. 6). The additional requirements and recommendations for these groups of soft fruit crops with respect to Integrated Plant Protection listed up in the chapters 10.1 to 10.3 are as follows: 10.1 Strawberry – Alleviation of harmful insecticidal effects on predatory mites by downward-directed

spraying. – Biological control of Two-spotted spider mites with Typhlodromics in protected crops. – Predatory mirids should be used to control Western Flower Thrips on prot. crops. – Entomopathogenic nematodes should be used to control vine weevil on prot. crops. 10.2 Cane Fruits – Biological control of spider mites in protected crops. – Regular monitoring of Byturus tomentosus by traps. – Raspberry Clearwing must be monitored with pheromone traps and infested shoots must be

pruned and removed. – Recommendation to prevent the development of cane diseases by removal of superfluous

canes and fruiting canes after harvest and reduced N input.

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10.3 Bush Fruits – Currant Clearwing must be monitored with pheromone traps and infested shoots must be

pruned and removed. – Phytosanitory activities for black currant crops:

– Monitoring currant gall mite and removal of infested plant material, – Monitoring reversion disease and removal of infested plants, – Nectria – infected branches should be removed.

In the general part of Chapter10 of TG III for soft fruit IP two points are of general interest. For the first time anti-resistance strategies with strict limits on the use of acaricides, insecticides and fungicides were included in a TG III. During the revision of TGs III for the other crops this also has to be done. Secondly in Integrated Plant Protection as described in IOBC - TGs III the use of crop protection products has follow certain standards comparable for all crops. IOBC – TG III for soft fruit IP permits the (very restricted) use of organochlorine pesticides for mite control thus not keeping up with the standard, due to the poor availability of registered pesticides in soft fruit crops in Europe. This IOBC – TG III explicitly has been developed for strawberry, raspberry, blackberry, currants, gooseberry, blueberry and elder. But:

Although only the major soft fruit crops are covered specifically, the same principles can be extended to other closely related minor soft fruit crops.

Acknowledgements The authors express their gratitude to the members of the expert panel, all the colleagues involved in the workshop discussions, the translators and the members of IOBC – Commission for their valuable help. References Abelson, P.H. (1995): Sustainable agriculture and the farm bill. Nature 267: 943. Allen, P., Van Dusen, D., Lundy, J. & S. Gliesman (1991): Expanding the definition of

sustainable agriculture. Journal of Alternative Agriculture 6: 34-39. Baggiolini, M. (1998): Integrated Production in Europe: 20 years after the declaration of

Ovrannaz, 2.1 Historique: 50 ans de souvenir. IOBC/wprs Bulletin 21 (1): 5-12. Jehle, J. (1998): Internationale Entwicklungen in der Gentechnologie im Obstbau. Mitt. OVR

53: 269-274. Meadows, D.H. et al. (1992): Beyond the limits. Report of the Club of Rome, Chelsea Green

Publishers Co., Post Mills, Vermont.

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pp. 167 - 169

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Work on Integrated Soft Fruit Production in Europe – Summarisation of the Workshop Erich Jörg Landesanstalt für Pflanzenbau und Pflanzenschutz, Essenheimerstr. 144, D-55128 Mainz, Germany General overview During the last five years interest in soft fruits is increasing. On one hand several soft fruit crops are of high profitability compared to pome and stone fruit crops where an oversupply throughout Europe must be stated. On the other hand soft fruits offer new fields of work for researchers. A look at Table 1 shows that the numbers of papers and posters on soft fruit crops presented at international conferences and workshops has increased from 1995 (13) to 1999 (31). In 1997 the first IOBC-Workshop dealing with Integrated Production of soft fruits was held and a specific subgroup working on these crops was founded. Table 1. Publications on soft fruit problems (IOBC conferences and workshops 1995-1999) Conferences / Workshops

Year Numbers of presentations

Straw-berry

Black Currants

Raspberry Blackb.

Goose-berry

Elder-berry

Cedzyna (PL) 1995 13 6 6 0 0 0 Vienna (A) 1997 19 8 2 2 0 1 Warszawa (PL) 1999 31 12 8 2 1 0

Strawberries and black currants are the main crops on which research is done. Much less activities are devoted to minor crops such as raspberries, blackberries, gooseberries or elderberries. Several crops (blueberries, cranberries etc.) have not been dealt with on the three international meetings. More than half of the reported results are on pests of soft fruit crops, among which spider mites, gall mites and weevils are quite well investigated. Some information on powdery mildew, Botrytis grey mould, Verticillium wilt and Phytophthora diseases of strawberries is available. Only a few results have been reported on weeds or application technique for soft fruit crops. Among the control measures resistance breeding is of greatest importance. Many reports are given on cultivar resistance to fungal diseases or mites and also ist limits and prospect have been shown. Research on biological control is mainly restricted to the use of Phytoseiid mites for the control of spider mites or gall mites. During the last three years many papers have been presented on the suitability of mainly fungicides but also insecticides/acaricides for Integrated Production of soft fruits. Recently decision support systems are elaborated especially for some pests and diseases of strawberries.

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Concerning regional participation in the IOBC - soft fruit work the situation is as follows. Most of the countries are present at the conferences/workshops. Poland as the most important producer of soft fruits contributes a lot to the success of developing Integrated Production for soft fruit crops. But still several relevant countries such as Spain, Italy or the Netherlands were not represented. Research work Two main streams of work on Integrated Production of soft fruit can be identified. They may be described as the „scientists` approach“ and the „extensionists` approach“. The first primarily aims at the development of more biologically based IP-systems where the use of agrochemicals is replaced by non-chemical alternatives. Research workers e.g. deal with the elaboration of new detection methods, the development of bio-insecticides and pheromones, faster breeding methods the identification of predators/parasites of important pests. The „extensionists“ try to introduce IP into practice by minimising pesticide and fertiliser input within certain limits and by developing IP-conform systems for minor crops. Main topics of their work are pesticide efficacy and side-effects, development of decision support systems, optimisation of spray application methods, utilisation of less susceptible cultivars and judging the (still incomplete) IP-systems by results of pesticide residue analyses. Complexity Most of the work presented at the meetings is based on a systems approach rather than focussing on single aspects. Good examples are the investigations: • on the whole Phytoseiid community with respect to the control of two-spotted spider mite

and inclusion of the orchard environment as a source for these beneficial organisms, • on both pesticide efficacy and side-effects from the beginning on, • on the whole life cycle of fungi (e.g. Strawberry powdery mildew) with respect to

forecasting and control, • on complex yield - loss relationships and implications for control necessity (e.g. Blossom

weevil on strawberries) and • on comprehensive cultivar assessments covering all relevant diseases and pests to optimise

cultivar choice. Interdisciplinary research Several papers indicated that research work on soft fruit fruits is interdisciplinary. E.g in order to reduce pesticide input to the minimum spray applicationists and agronomists closely cooperate to develop appropriate growing systems. International cooperation Especially among breeders of soft fruit crops there is a good international cooperation and an exchange of planting material. But also concerning the development of advisory systems for some crops (e.g. RACER for raspberries) colleagues collaborate throughout Europe. IP-Guideline for soft fruit production In quite an early stage compared to pome and stone fruits a guideline for IP of soft fruits has been elaborated. In general this guideline keeps up with the standards of the comparable guidelines for pome and stone fruits. However, in some essential points (e.g. pesticide use)

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improvements are necessary and in so far the IP-Guideline may also serve as a guideline for steering research activities in the near future. Several intensive production systems for soft fruit crops are not covered by the guideline as they are regarded as „non-sustainable“. So after a general discussion of sustainability the soft fruit guideline probably has to be revised. Further activities The main challenges for both scientists and extensionists in soft fruit production were highlighted by Cravedi & Jörg (1996). They gave a rough and surely incomplete overview on the most striking pest and disease problems, the control measures available, the significant gaps in our knowledge and on the fields of work to which research activities shall be devoted primarily. As a supplement Jörg (1998) reviewed the availability of plant protection products and their suitability for an Integrated Production of soft fruits. Some of the problems made evident by the authors are at least partly solved now while others still exist. An actual and more comprehensive overview is needed on the status of Integrated Production of soft fruits comparable to the one given by Cross et al. (1996) for pome fruit IP. This overview should include informations on the: • growing areas of the various soft fruit crops; • different production systems (in-soil, non-soil; protected, open field; etc.); • biological constraint systems for the soft fruit crops (dominance structures of pests,

diseases etc.); • availability of biological and biotechnical control measures and cultivars of low

susceptibility; • availability of plant protection products; • implementation of Integrated Production into horticultural practice and on the • most urgent problems to be solved. On the basis of the results of this overview common research activities can be planned and the fruitful work that started with the two IOBC - Soft Fruit Workshops at Vienna and Warszawa can be continued. References Cross, J.V., Bonauer, A., Bondio,V., Clemente, J., Denis, J., Grauslund, J., Huguet, C., Jörg,

E., Koning,S., Kvale, A., Malavolta, C., Marcelle, R., Morandell, I., Oberhofer, H., Pontalti, M., Polesny, F., Rossini, M., Schenk, A., Schaetzen, C. de. & M. Vilajeliu, 1996. The current status of Integrated Pome Fruit Production in Western Europe and its achievements. IOBC/wprs Bulletin 19 (4): 1-10.

Cravedi, P. & E. Jörg, 1996. Special challenges for IFP in stone and soft fruit. IOBC/wprs Bulletin 19 (4): 48-56.

Jörg, E., 1998. Pesticide availability in European soft fruit production. IOBC/wprs Bulletin 21 (10): 5-15.

16 September - IOBC-WPRS

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