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Page 1: O. zaidan tomato production

By Omar Zeidan

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Table of ContentsTABLE OFCONTENTS

PREFACE ………………………………………………………………....FOREWORD ………………………………………………………………INTRODUCTION ………………………………………………………PLANT MORPHOLOGY ………………………………………………CLIMATIC FACTORS AND THEIR INFLUENCE ON TOMATOES…….GREENHOUSES FOR TOMATO PRODUCTION ……………………….NET HOUSES FOR TOMATO PRODUCTION …………………………..GREENHOUSE COVERING FILMS…………………………………PREPARATION FOR NEW CROP…………………………………IMPROVING CLIMATE CONDITIONS IN SUMMER AND AUTUMN……SEEDS, SEEDLING PREPARATION AND TRANSPLANTING…………TRAINING METHODS………………………………………………………PLANTING SEASONS………………………………………………………TABLE TOMATO VARIETIES………………………………………CHERRY TOMATO VARIETIES………………………………………GROWING TOMATOES FOR CLUSTER HARVESTING…………………NEW TOMATO PRODUCTS…………………………………………………PARTIAL RESISTANCE TO ROOT KNOT NEMATODES…………………ROOTSTOCK AND GRAFTING……………………………………………POLLINATION AND FRUIT SET OF GREENHOUSE TOMATOES……IRRIGATION AND NUTRITION……………………………………………MICROELEMENT DEFICIENCY IN TOMATO PLANTS……………………SOIL SALINITY…………………………………………………………………GROWING TOMATOES IN SUBSTRATES (Soilless Culture)…………RECYCLING DRAINAGE WATER ………………………………………….GREENHOUSE VENTILATION………………………………………GREENHOUSE HEATING……………………………………………CO2 ENRICHMENT FOR TOMATOES…………………………………ETHYLENE DAMAGE………………………………………………………GROWTH AND FRUIT DISORDERS………………………………………TOMATO HARVESTING AND POSTHARVEST…………………………ETHERAL TREATMENT TO ACCELERATE TOMATO RIPENING……OVER VIEW OF ORGANIC PRODUCTION OF TOMATOES…………DISEASE AND PEST CONTROL……………………………………………CHEMICAL SPRAY APPLICATION TECHNOLOGIES…………………NON-PARASITIC DISORDERS………………………………………WEEDS AND PARASITIC PLANTS………………………………………SOIL-BORNE DISEASES……………………………………………TOMATO LEAF DISEASES……………………………………………BACTERIAL DISEASES……………………………………………VIRAL DISEASES…………………………………………………………PESTS……………………………………………………………………BIBLIOGRAPHY……………………………………………………………

iii125710101215182023242729303434364146485057585961616266717274767880818388899397

1.2.3.4.5.6.7.8.9.

10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.

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PrefacePREFACEHigh-quality vegetable production, particularly tomatoes, holds animportant part in the global fresh horticultural food basket. We thereforefeel the need to transfer and adapt the knowledge and technology thathas been compiled in this field in Israel and make it available to English-speaking agricultural extensionists, specialists, growers and entrepreneurs.

Tomato production has special relevance to the Mediterranean andMiddle East countries. The compilation of this publication can be usedas professional input for the regional Middle East and MediterraneanProgram of Integrated Crop Management initiated by the Peres Centerfor Peace in cooperation with countries in the region. Tomato productionand post-harvest care are a priority in the activities of its cooperationprograms.

The newly published publication, Tomato Production Under ProtectedConditions, was written by Mr. Omar Zeidan, Director, Vegetable GrowingDepartment and Assistant Deputy-Director of the Extension Service,Ministry of Agriculture and Rural Development, in 2001.Mr. Zeidan is also recognized as a highly experienced tomato specialistin international circles.

This manual was translated from the original Hebrew document of theExtension Service of the Israel Ministry of Agriculture and RuralDevelopment. The professional strength and relevancy of the topicmotivated and initiated the parties, MASHAV, CINADCO and the PeresCenter for Peace, through the Andreas Agricultural Development Trust,to publish the manual in its English version.

The publishers wish to acknowledge and thank the Extension Serviceof the Israel Ministry of Agriculture and Rural Development for theirprofessional contribution and cooperation in this endeavour.

We envisage that this publication will contribute to the production of high-quality produce resulting in increased farm income and economic growth.We also hope that Tomato Production Under Protected Conditions willenhance the sharing of know-how as a means of strengthening theprofessional and people-to-people links of the countries in the regionand beyond.

i

Zvi Herman DirectorCINADCO

Ministry of Agriculture andRural Development

Prof. Samuel PohorylesDirector

The Andreas AgriculturalDevelopment Trust

The Peres Center for Peace

Moshe GorenDirector

Extension ServiceMinistry of Agriculture and

Rural Development

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ii

ForewordFOREWORDThis manual is intended for professionals and farmers involved ingreenhouse tomato growing and marketing, locally and/or for export.The manual includes principles of tomato growing in order to help thegrowers understand the basic stages that guarantee a successful crop.The material in this manual is based on technological knowledge andexperience that has been accumulated in Israel over the years for thebetter use of greenhouses, nurseries and net houses for tomato production.

The chapters in this manual are written according to the order of stagesrecommended in establishing a new greenhouse project and accordingto the order of activities in growing tomatoes, from the planning stageuntil the final growing stages.

The agro-technical instructions, planting times, fertilization, irrigation,pollination and other activities are based on numerous research findingsand field tests that were conducted at various sites throughout Israel.Research institutions, scientists, extension workers and growersparticipated in and contributed to the establishment of this advancedagro-technological branch.

Thus, this manual includes professional and scientific principles that canprovide basic training for students, support for field extension staff andguidelines for marketers of agricultural output in Israel and in countriesthroughout the world that participate in Israel’s international cooperationprograms. We are happy to share the professional material presentedhere, however, we wish to point out that these are recommendationsonly and should not take the place of detailed and certified local engineeringplanning.

It is my pleasure to thank CINADCO, The Centre for InternationalAgricultural Development Cooperation of the Ministry of Foreign Affairsand the Ministry of Agriculture and Rural Development, the Peres Centerfor Peace, through the Andreas Agricultural Development Trust and themany experts and professional staff of the Israel Ministry of Agricultureand Rural Development, Extension Service, who read the draft of thismanual and submitted their helpful comments in order to make thispublication possible.

Director, Vegetable Growing Dept. and Deputy Director, Extension Service,Ministry of Agriculture and Rural Development

Omar Zeidan

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1

Common name: TomatoScientific name: Lycopersicon esculentum Mill.Family: SolanaceaeThe tomato plant originated in Peru and Mexico, in present day Centraland South America. The tomato reached Europe from Mexico in the 16thCentury, and was initially used as an ornamental plant. At the end ofthe 18th Century, the tomato started to be produced as an edible cultivatedplant for household use. The tomato only reached Israel in the 19thCentury.Tomato production is currently considered to be one of the main vegetablecrops, and constitutes an economic force that influences the income ofmany growers in the world.In Israel, tomatoes used to be planted in greenhouses in the fall, especiallyin the western Negev desert, with the aim of developing tomato productionfor export to Europe and other destinations. This crop was characterizedby a limited yield season from December to March. However, technologicaldevelopments and innovative growing methods expanded crop productionto other areas in Israel and is now year round in greenhouses and net-houses.Contamination of open-field tomato plants by tomato yellow leaf curlvirus (TYLCV) requires intensive and multiple spraying against Bemisiatabaci (whitefly). This encouraged transition to growing of tomatoesunder protected conditions, in both greenhouses and net houses.The conventional production methods in Israel, which are described inthis booklet, are similar to conventional methods applied in manyMediterranean and Latin American countries. Therefore, therecommendations in this booklet may be useful for growers in thesecountries.Export of regular tomatoes from Israel has recently declined, due to thelarge supply of tomatoes in international markets from supply sourcesthat are close to the European markets, such as Spain, Morocco andother Mediterranean countries.Since tomato production targeted for the export market is a source oflivelihood for many farmers, in order to remain competitive, they mustproduce high quality tomatoes with unique and marketable characteristics.Following the decline in demand for regular tomatoes, two innovativeproducts were developed: cherry tomatoes and cluster tomatoes, bothof a very high quality, for export to European and USA markets. Othertomato products such as cluster cherry tomatoes and extra-sweettomatoes grown in brackish water have also been developed, but on asmaller scale.Continuous research, the breeding of new varieties, as well as thedevelopment and implementation of innovative agro-technical methods,are a guarantee for continued production and supply of tomatoes forlocal consumption and export, and in the future will enable the growersto maintain their competitive status.

INTRODUCTION1.

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2. PLANT MORPHOLOGY

Leaves: In most varieties, the leaves consist of twopairs of serrated leaflets and a terminal leaflet. Smallsecondary leaflets develop between the leaflets. Theleaves of the tomato plant, like the stem, are covered withfine hairs.

Inflorescence: Inflorescence appears on the main stemand lateral branches. The number of flowers perinflorescence is determined according to the varieties andgrowing conditions. Varieties with a small fruit (cherrytomatoes) have 50 and more flowers per inflorescence.Varieties with a regular-sized fruit usually have between 4and 10 flowers per inflorescence in optimal conditions.However when flowering begins and temperatures are veryhigh, there may be fewer flowers per inflorescence. On theother hand, when temperatures are low, there are moreflowers per inflorescence.

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Growth habits of tomato plants: Determinate growth: These tomato plants are relatively

compact and grow to a certain height. They flower andset all their fruit within a short time. The main stem andlateral branches terminate in two consecutive inflorescencesafter a number of nodes, according to variety. In thesevarieties, the number of inflorescences per stem is notfixed. Determinate varieties can be grown in open fields,spread out over beds or trellised on sticks, if the varietieshave a strong growth. Indeterminate growth: Indeterminate tomato plants

grow continuously, producing flowers and fruit over a longperiod of time until the grower or weather conditionsterminate the crop. The main stem and lateral branchescontinue to grow and the number of leaves betweeninflorescences is more or less fixed.In these varieties, the inflorescences appear with a setnumber of leaves between the inflorescences on the mainstem and lateral branches. Indeterminate varieties canbe grown on trellises in open fields and greenhouses, andthe plant is shaped by pruning the lateral branches.

Roots:Development of the tomato plant’s root system dependson the growing method, type of soil and irrigation regime.In soil-less culture, roots develop according to the sizeand shape of the growing container. The root system inlight soil is not as deep as the root system in medium-heavy soil. Plants that are grown directly from seeddevelop a denser root system than plants that arepropagated or prepared in a nursery. When unrestrictedby disease or soil type, tomato roots can reach a depthof 1.5 to 2 meters. However, the active part of the rootsystem is not as deep. Under high humidity conditions,adventitious roots may develop together with the naturalroot system, but these roots do not contribute to plantdevelopment.

Stems:The growing shape, number and lengths of stems differaccording to the varieties and growing methods. Sympodialgrowth in tomatoes is characterized by a main stem thatterminates with inflorescence after the appearance of acertain number of leaves and nodes.A lateral branch grows from a lateral bud, and again anumber of leaves, nodes and inflorescences develop, andso on.

Table 1. Number of leaves below firstinflorescence and number of leavesbetween inflorescences on the mainstem

DeterminateIndeterminate

Below firstinflorescence

Between first& secondinflorescence

Third and moreinflorescence

6-14

3-5

3

6-14

2-3

0-1-2

Temperature has a significant effect on the timing andposition of the first and second inflorescence on the mainstem in relation to the number of leaves. When thetemperature is high, appearance of the first inflorescencetends to be delayed. There are many leaves below thefirst and the second inflorescence. When the temperatureis low, the number of leaves below the first inflorescencedecreases and there are only a few leaves on the mainstem below the flowering.

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Fruit:Mature tomato fruits are mainly red. However somevarieties have fruit of a different color: pink, orange andyellow. The fruit is succulent and its shape varies accordingto variety and can be: globe, flattened globe, deep globe,flat or ribbed. The size of the fruit also varies accordingto variety: fruit of cherry varieties weigh between 8 and20 grams, and large fruit varieties weigh up to 250 grams.Hereditary factors usually directly influence the size andshape of the fruit. However growing conditions and positionof inflorescence on the plant also influence the growthand weight of the fruit.The tomato fruit can be characterized according to thenumber of locules (carpels): round, small and medium-sized fruit usually have two or three locules while flat andlarge fruit have about ten to twelve locules.Descriptions of tomato fruit include fruit with green shoulders(U+), and fruit without green shoulders (uniform = U).The absence or presence of green shoulders is a geneticfactor. Direct exposure to sunlight of a green shoulderedfruit deepens the green color and can even turn it to yellow.The foliage cover is the most effective way to reduce thisphenomenon.Tomato fruit is defined as a joint fruit with an abscissionpoint on the peduncle.Most fresh market fruits are picked with the calyx. Whenthe fruit pedicel has no abscission point it is defined asjointless. Joint varieties are used when growing processingtomatoes because the fruits separate easily from the calyx.On the other hand fruits of fresh market cluster tomatoesare often jointless but are attached more firmly to theclayx.

Flower:The flower is usually composed of six green sepals, sixyellow petals and six stamens. The pistil is composed ofan ovary, a long style and a simple and slightly swollenstigma. The ovary has between 2 and 20 ovules, shapedaccording to variety, and it reflects the shape of the fruitthat will develop.

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Fruit with many locules

Female parts of tomato flower

Natural tomato flower

Fruit with 3 locules

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Changes in the fruit during ripening stagesAfter the fruit has reached the mature green stage, rapidchanges start to occur in the fruits. The chlorophyll graduallydisappears, and at the same time, other pigments arecreated in the fruit, especially lycopene and b carotene.The b carotene concentration reaches a maximum levelin the initial ripening stages, while the lycopene levelincreases as ripening nears completion, and even later.The estimated time from the mature green stage to fullripening of the fruit (90%) is about ten days. There are nosignificant changes in vitamin C level and total solublesolids (TSS) during the ripening process, although invarieties with a smaller fruit, sugar continues to accumulatein the advanced ripening stages. Aroma and flavorcompounds also increase during the ripening process.However in this process the fruit is less firm, and its toleranceto cracking and sunburn increases. A red fruit is lessdamaged by sun. However when a green fruit is suddenlyexposed to sun, it is severely damaged and the damageis apparent when the fruit is still green and also when itturns red. The pH level also decreases gradually duringthe final ripening stages, due to the increase of citric andmalic acids. Temperatures affect development of the tomatocolor: lycopene, which gives the tomato its red color, is notproduced at temperatures over 30ºC. However productionof ß carotene, which gives the tomato its yellow color,

continues. Production of ß carotene stops in temperaturesover 40ºC. The best color of tomato fruits is produced atoptimum temperatures between 20-24ºC.

Firmness and shelf lifeFirmness and shelf life are characteristics of high qualitytomato varieties, which are required for long distancetransport for both local and export markets. The mostsignificant method for acquiring firmness and shelf life isby breeding and developing varieties with firmness. Thegreat success in acquiring this characteristic has beenreinforced by Israeli geneticists who successfully introducedripening-inhibitor genes into new hybrids. Amongst thegenes known to inhibit ripening are the RIN and the NORgenes. Varieties heterozygous to the RIN gene (+/RIN)usually have a shelf life that is 20 - 50% longer than regularvarieties, and varieties heterozygous to the NOR gene(+/NOR) have a longer shelf life, exceeding regular varietiesby 50 - 100%. It is important to remember that fruit fromvarieties that have the NOR gene should be picked whenpink or even more mature. Fruit picked before this stagewill not develop the proper red color and the quality of thetaste will be lowered.FlavorThe flavor of tomatoes is influenced by the compounds ofthe fruit and the ratio between them. The tomato fruit ismostly water, with solids constituting only 5-7% of the fruit. About 50% of the solids are sugars (mainly fructose andglucose), and about 12% are organic acids (malic andcitric acids).The tomato fruit includes other compounds in smallquantities, such as minerals (K, Ca, Mg, P), proteins,pectic substances, pigments, amino acids, volatiles,vitamins, ascorbic acids and polyphenols. All thesecompounds affect the flavor and aroma of the tomatoes.In general, aroma and taste can be influenced bybreeding/genetics. Agrotechnical activities also significantlyinfluence improved taste.

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Changes graph

4

Development of ripening

Green mature

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3

Temperature has a significant influence on the tomatoplant’s fertility and directly affects both yield and productquality. There are extreme disorders in the tomato plant’sfertility in winter, when day and night temperatures arelow - below 18ºC and 10ºC respectively - and in summer,when the day and night temperatures are high - above32ºC and 22ºC respectively.The morphological and physiological changes in the tomatoplant, which are affected by temperature, are describedhere:

TemperatureTemperature is the main climatic factor which influencesmost of the tomato plant’s development stages. The optimaltemperature for growing tomatoes is between 22ºC and26ºC during the day, and between 14ºC and 17ºC at night.Extreme temperature fluctuations may damage the tomatoin the different growing stages.

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CLIMATIC FACTORS ANDTHEIR INFLUENCE ON TOMATOES

Table 2a. The tomato plant’s temperature requirements in the different growing stages

Exposure to high temperature:Reduction of pollen viability and quantity in the flowersReduction of number of flowers in inflorescenceAppearance of poor and weak inflorescencesDistortion of the anthersElongation of the style beyond the antherAsymmetry in the inflorescence shapeDelay in appearance of first inflorescence on the main stemMorphological changes - elongation of the plant’s internodes

Minimum(ºC)

Germination

Growth

Fruit set at night

Fruit set in the day

Production of red pigment - lycopene

Production of yellow pigment - ß carotene

Chilling injury

Frost (freezing)

Storage of pink and red fruit

Growing stage Optimum(ºC)

11

18

10

18

10

10

16-29

21-24

14-17

23-26

20-24

21-23

6for some hours(-2)-(-1)

10-12

34

32

22

32

30

40

Maximum(ºC)

Elongation of the style beyondthe anthers Asymmetry in inflorescenceFew flowers in inflorescence

Effect of high temperature

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Radiation and daylightIncreased radiation intensity stimulates vegetative growthand results in higher yields, mainly due to increasedassimilation and production of dry matter. In many plants,the growth rate in the dry weight per area unit is influenced

Continuous exposure to low temperature:Reduction of pollen viability and quantityDistortion of ovary and increased incidence of fruitdeformationElongation of the ovaryDistortion of the stamenIncreased number of flowers in inflorescenceShort internodes and compact plants

Relative humidityRelative humidity of 65% to 85% is beneficial to thedevelopment of the tomato plant. This is expressed inoptimal growth and fertility. Higher relative humidity resultsin irregular release of pollen grains from the anthers andunsatisfactory distribution on the stigma. High relativehumidity also creates conditions for development of variousleaf diseases, such as late blight, caused by Phytophthorainfestans, Botrytis, and Erwinia.

Incidence of blotchy ripening increases in high humidity.On the other hand, in relative low humidity, there may below fertility as the pollen grains dry out on the stigma even

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The data in the table clearly indicate the damage to thefruit and fruit quality caused by excessive shading, whichresults in insufficient radiation.

by radiation, more than by any other environmental factor.A positive correlation was found between this rate andradiation intensity. When examining the assimilation rateof tomato plants, it was found that the lowest assimilationrate was recorded at low radiation intensity in December(Israel), approaching the shortest day of the year, whilethe maximum assimilation rate was recorded at highradiation intensity in summer. In winter, the photosyntheticradiation quantity is the principal factor that determinesgrowth rate, while in summer, the radiation intensity isusually sufficient, and growth may be restricted by otherfactors.Tomato plants are usually indifferent to daylight hours andphotoperiod, however when the radiation intensity is low,there is a negative influence on the plants and on the yieldcomponents, as a result of lack of radiation in greenhousesduring the winter months. The yield and its quality areseverely damaged by artificial shading or excessiveaccumulation of dust on the external covering sheets,which reduce the quantity and intensity of the radiationpenetrating into the greenhouses.In an experiment conducted in the Besor experimentalstation in Israel’s southern desert, a significant reductionin the number of fruit in inflorescence and ripeningpercentage was found with 12, 34 and 55 % shading oflight intensity (according to A. Sagie). Shading was alsofound to have a negative influence on the percentage ofhollow (puffy) and blotchy fruit.

Table 2b. Influence of shading onfertility and ripening of tomatoes inthe Besor experimental station

Percentage ofundeveloped

fruit set

Shadingpercentage Fruit in

inflorescenceNumber offlowers in

inflorescence

Number offlowers in

inflorescence

12

34

55

10.0

10.4

9.0

7.1

6.7

5.6

71.0

66.0

63.0

29.0

32.0

41.0

Elongated fruit (Lemon shape) – low temperature

Short internodes, distortion andcracks in stem - low temperature

Deformations with cat face – low temperature

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4 GREENHOUSES FORTOMATOPRODUCTION

Growing tomatoes in greenhouses is a means to isolateplants from the environment, allowing growing conditionsthat are suitable for development of the plant and productionof a high quality and quantity yield.In greenhouse production, tomato plants are grown on asingle stem or two stems per plant, according to the varietyand season. In this method, the plants grow vertically onstrings or trellises and are arranged in single or doublerows on the beds. In order to achieve a maximum yield,technologies should be adapted to the growing conditions.Some important considerations are the shape and positionof the structure, covering material, insect-proof nets,heating and cooling methods and a large range ofaccessories. These technologies enable production underoptimum condit ions, or improved condit ions.When planning the greenhouse, the distance betweenthe greenhouse units should be considered, so as to allowefficient ventilation for the regulation of temperature andhumidity. Additional things to consider are how to optimizethe workers’ time when moving among the structures andthe convenience entailed when performing agro-technicaltasks, such as cultivation, harvest and spraying. Thegreenhouse design should facilitate transportation of theproduce from the greenhouse to the packing house.

Advantages of greenhouse production1. Protect ion from harsh cl imatic condit ions

Rain and hail Low temperature Winds and Storms Dew and excess humidity

2. Control over climatic factors Heating Cooling Shading CO2 enrichment

3. Adaptation of production and marketing to local andexport market requirements

Production during different growing seasons Production and marketing over an extended period Continuous supply

4. Savings in production costsIncreased yield per unitIncreased efficiency of agricultural inputs

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Convenient operation5. Decreased use of pesticides

Use of nets and films to keep out insects6. Improved product quality

Use of quality varietiesUniform fruit shape, color and size Use of varieties with a long shelf life

Characteristics1. A greenhouse for growing tomatoes should be designed

to hold a vertical load of 35 kg/m2.2. The greenhouse should be planned and approved by

an authorized engineer.3. The building materials should be durable: concrete,

galvanized steel, wood treated by impregnation, weldingafter galvanization coated with zinc-rich paint. Thescrews should be galvanized and vibration-resistant

4. The gutter direction should be north-south, to allowmaximum penetration of light and minimum shade onthe plants throughout the day.

5. If the greenhouse does not have roof vents, its length(gutters) should be limited to 36 - 40 m. The width,which is composed of the gable spans, is unlimited.

6. If the greenhouse has roof vents, its length and widthis not limited.

7. The gutter height required for producing tomatoes ontrellises over a long yielding period is at least 4 m.

8. There should be a distance of 10 to 12 m, or at leastthe equivalent of twice the structure height, betweennearby greenhouses.

9. The greenhouse should be able to withstand winds of150 km/h, and it should have a life span of at least tenyears.

10. It is recommended to install porches around thegreenhouse to reinforce its resistance to strong winds.

11. The greenhouse should be constructed on a 0.5%-1%linear and lateral slope, for efficient drainage ofrain and in soilless culture for the surplus irrigationwater.

12. There should be accessible approaches to and fromthe greenhouse for passage of agricultural equipmentand convenient transport and removal of fruit.

Notes:A. These principles are suitable for the conditions in Israel

and for countries with a similar climate. There are othergreenhouse models which are compatible with localconditions, such as in Almeria, Spain.

B. The above information relates only to polyhouses.

Essential accessories1. Roll-up curtains on each wall. The curtains on the long

side should be divided into two or more sections.2. Double entrances for convenient movement of produce.3. Preparation for connection of an insect-proof net by

installing horizontal beams on the wall at a suitableheight. It is recommended to install insect-proof netsat all openings to ensure complete sealing of thegreenhouse.

before germination. This results in partially fertilized,small, deformed and hollow (puffy) fruit. At relatively lowhumidity and high temperature, there is a high and rapidevaporation rate of water from the leaves. In theseconditions, the root system cannot supply the water volumerequired for evaporation via the leaves, and in extremecases, this may lead to partial wilting of the plant growingtip and increase of blossom end rot, which stems from ashortage of calcium (Ca) in the fruit tissue. It was foundthat excessive humidity in the greenhouses may reduceevaporation from the leaves, inducing root pressure onthe fruit. This increases incidence of fruit cracking.

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Span widthGreenhouses have different span widths. The type ofcovering greatly influences the span width when planningthe greenhouse. For example, when a rigid covering isused, greenhouses can have a span width of 9 or even12 meters. In this case, there will be fewer gutters perhectare, and there will, of course, be less shading on theplants. When a flexible covering such as plasticpolyethylene sheets is used, the greenhouse should havea span width of 6 to 8 m. Plastic coverings are sensitiveto climatic conditions and are susceptible to tearing. Forexample, in very hot weather, the sheets become tooslack and their grip on the frame is reduced. The sheetsmay also be damaged and tear during storms.An important consideration is that damage to the sheetsmay be partial, and they may be easily repaired or replacedat a relatively low cost. When the covering is flexible,the spans are narrower and therefore more gutters arerequired, so there is more shading compared to a wide-span greenhouse.

4. Climate control equipment. The greenhouse shouldbe prepared for installation of climate-control equipment,such as heating and air circulation fans, equipment forapplying pesticides and a thermal screen. The positionof the heater should be determined in advance toenable convenient access for ongoing maintenanceand refueling.

5. Vertical beams should be installed on the greenhousewalls, perpendicular to the crop rows. A crop wireruns from wall to wall. Long greenhouses with a pathin the middle should have support poles in the center,and the crop wire should be divided into two.

6. The crop wires that are parallel to the crop rowsare made of soft galvanized steel, and have a diameterof 3 - 3.5 mm.The wires should be stretched between the two beamsat either end of the greenhouse.

7. An infrastructure for soilless culture, recycling ofdrainage water and collection of rainwater.

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Greenhouse roofsThere are many types of greenhouses on the market, withdifferent span widths and roof models. Some structureshave an even-span roof, which is especially suitable forrigid covering, such as glass or polycarbonate. Structureswith a gable or arch roof are mainly suitable for plastic(flexible) coverings. A flexible covering on an arch roofenables the covering to be firmly attached and properlystretched, to prevent fluttering. This saves the investmentin a ridged or fixed roof such as glass. A rigid polycarbonatecovering is flexible in a certain direction and it can beplaced on curved roofs. Choice of roof shape will beadapted to the type of future covering and cost of coveringmaterial. In Israel and the Mediterranean Basin,polyethylene plastic films are usually used.Rigid coverings are not common in Mediterranean countries,for the following reasons:

High cost of constructionThe greenhouse frame, especially the roof, would needto be adapted to rigid covering materialRadiation transmission through these materials (notglass) could be reduced, as a result of reducedtransparency after a few years.

Diagram of greenhouse

Types of roofs

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Roof and side ventilation protected by net Roof ventilation protected by netSide ventilation protected by net

Roof ventsRoof, gutter or ridge vents are vents which open alongthe length of the span. The hot air, which accumulatesin the greenhouse, rises and is trapped in the upper partof the greenhouse (in the triangles), where it has a greatinfluence on the heat load in the greenhouse. A ventopening in the greenhouse roof releases this heat andgreatly reduces the heat load. Release of heat througha roof vent in greenhouses with rigid coverings, such asglass, has been applied for many years in Israel and othercountries. However, in greenhouses with plastic coverings

in Israel, installation of a vent along the span is not anoption, due to the labor required every year to seal thegreenhouse for heating and to keep out insects, whichserve as vectors for viruses.Developments in the greenhouse industry, the manymanufacturers and the competition between them, haveled to the development of new greenhouse models withroof vents which are also suitable for plastic coverings. Itis important to install insect-proof nets in the roof vents.All roof vent models can be opened manually or by acomputer-controlled motor.

Roof vents

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5Net houses for tomato production provide growingconditions that are similar to those in greenhouses, witha relatively low investment. Growing in net houses shouldbegin and terminate in seasons when the climatic conditionspermit it. Therefore, growing should be planned so thatmost of the yield is harvested before temperatures dropand the rainy season begins. If even the lightest rainpenetrates the nets and wets the plants, the fruit will crack,its quality will drop and in addition, the prevalence of leafdisease will increase, especially early blight (Alternariasolani), late blight (Phytophthora infestans) and leaf mold(Fulvia fulva).In the Israeli and Mediterranean climate, tomatoes areplanted in net houses in the spring or early summer. Inthe rainy season and when humidity is high, the plantsmay be severely damaged.The net house should be completely covered with insect-proof net (50 mesh), to protect against invasion of insectsand the following specifications should be strictly adheredto.

NET HOUSES FORTOMATOPRODUCTION

Specifications1. Net house height: 3.5-4.0 m2. Recommended unit size: 1 ha3. Suitable for simultaneous hanging of two nets: 50 mesh

covering and internal shading screen, according toneed

4. Crop wires attached to structure5. Spaces between poles: 4x4m or 4x6 m

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6. Double entrance, recommended in the center of thenet house, to allow passage of a tractor for cultivationand preparation of soil, loading produce and otheragro-technical activities.

7. The net is tied to the structure with 6-8 m straps, andburied in the ground around the frame.

8. The poles are anchored in the ground.9. The section of the net that is anchored in the soil and

the lower part of each pole are treated with tar up to20 cm above ground level.

10.The pole tops are protected with plastic to preventfriction and tearing of the net.

11. Materials: 2.2 mm thick, hot-dipped galvanized poles12.Steel cables to withstand 120 km/h winds13. A gable structure with gutters is preferable to a flat

one.14. Anchors around the structure are according to the

manufacturer’s specifications, examined and approvedby an authorized party.

15. It is recommended to purchase the structure from anauthorized manufacturer.

Greenhouse covering films isolate the plant from theexternal environment, and its properties influence itsrelationship with the environment. The most commoncoverings are made of plastic materials.Most of the flexible films used to cover greenhouses aremade of polyethylene (PE). PE has many advantages,including: light weight, relatively low cost, flexibility,transparency, easy handling and ability to withstand diverseclimatic conditions.The properties which are required by films for coveringgreenhouses in general and greenhouses for tomatoproduction in particular, can be divided into two maincategories: mechanical properties, and optical and thermalproperties.PE covering films with a thickness of about 120 micronare usually used for one year. Thicker films are used formore than one year.Mechanical propertiesThe mechanical properties are defined in Israeli Standard821, and relate to sheet strength, tensility (ability to endurestress), durability, parameters related to dimensions (length,width, thickness, density), and permitted deviation rate.UV stabilizer is the main additive in sheets, and is mostimportant in determining mechanical properties. Thisadditive provides the sheet with durability and resistanceto radiation ageing and prevents its degradation.Optical propertiesOptical properties have a decisive influence on the yieldlevel, fruit quality and energy balance in the greenhouseand the behavior of pests and diseases.

Net house with gable roof

Net house with flat roof

6 GREENHOUSECOVERING FILMS

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11

Diagram of net house - gable and flat roof

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Optical properties can be classified according to theirinfluence on the different radiation fields:1. Thermicity: IR additive enables sheets to absorb or

reflect infrared radiation in the range of 7 to 15 microns(IR 7-15), retaining the heat that accumulated duringthe day (energy).

2. Visible l ight (400-700 nm): maximum lighttransmission is required for proper plant developmentand optimum photosynthetic efficiency.

3. Light diffusion: This is important in greenhouse tomatoproduction, where there is a high degree of shadingamong the plants. High radiation diffusion helps toincrease photosynthetic efficiency in the shaded partsof the plants in greenhouses.

Special additivesCertain additives in the film coverings have a positiveinfluence on the plants due to secondary effects. Theseinclude the following additives:1. UV absorption: UV absorption or UV blocking additives

reduce pest damage and prevent spread of viraldisease in tomato plants, as insects becomedisorientated in a UV-free environment.

2. Anti-drip: This additive prevents condensation in aform of droplets on the sheets and consequent drippingon the plants, reducing incidence of diseases whichdevelop in moist conditions. Light transmission isalso more efficient when there is no condensation onthe films.

3. Anti-dust: This innovative and unique additive preventsaccumulation of dust on the outside layer of the film,so that radiation penetrating into the greenhouse isnot reduced. This saves the labor which is requiredto wash the accumulated dust off the covering.

4. EVA (ethylene vinyl acetate): EVA improves the film’smechanical and optical properties, as well as its heatretention capacity.

Protecting the film coveringAs well as the additives that are designed to reinforce thefilms, it is recommended to apply white acrylic paint to theoutside of the film’s contact points with the frame. Thisprevents degradation when the metal frame overheats.The upper side of the metal arch can also be painted whitebefore construction of the greenhouse. White plastic tapeadhered to the metal also prevents heating of the metaland decrease wear of the film at the contact points withthe frame.Insect-proof netsInsect-proof nets in greenhouses for tomato productionare defined as 50 mesh screens (50 openings per inch),and are designated to prevent infiltration of tobacco whitefly(Bemisia tabaci) - a vector for tomato yellow leaf curl virus(TYLCV) – and other insects. These screens, which weredeveloped in Israel, contribute greatly to reduced use ofpesticides, as they physically block passage of insectsinto the greenhouses. Reduced pesticide applicationenables the use of bumblebees for pollination of tomatoflowers in greenhouses and net houses.The 50 mesh screens were approved for use after havingbeen determined as impenetrable by tobacco whitefly, andfrom the aspect of their mechanical properties andresistance to air passage at different pressures.The screens are made of interwoven 22-24 micron threads

Soil preparationMost soil types are suitable for tomato production, exceptfor heavy limestone and poorly drained soils. However,in order to produce a high-quality fruit, it is recommendedto grow tomatoes on light or medium sandy soil. In regionswhere the soil is heavy, claylike and impervious, it isrecommended to grow tomatoes in soilless culture.For further details, see section on Soilless Culture.Well-crumbled growing soil, which is level and smooth, isimportant for proper planting and uniform depth. Uniformand rapid establishment of the plants greatly depends onthe quality of soil cultivation which is completed before soilsterilization and planting. The soil is cultivated to a depthof at least 35-40 cm. A shovel plow enables cultivationclose to the greenhouse poles, and does not leaveuncultivated rows or open furrows in the middle of thespans.In medium and heavy soils, it is recommended to cultivatedeeply once every two years, using a vibrating plow, whichpenetrates 60-70 cm into the ground.The plowing is needed to open up soils which becamesealed and compact due to the continuous growth especiallythe walking area. This deep plowing improves aerationof the soil and drainage of surplus water, preventsaccumulation of salts and improves soil sterilizationtreatments. After initial cultivation, fertilizers are appliedand the soil is irrigated with a sprinkler system. After 5-8days, the ground is cultivated to crumble the earth clodsand to continue preparing the soil for sterilization. Thereis no need to build raised beds for tomato production ingreenhouses and net houses. It is sufficient to determineand mark the paths between the rows and to avoid walkingon the growing area.

12

and are UV stabilized against radiation damage, whichprovides them with durability.BioNet© screens have recently been introduced to themarket. This is a 50 mesh screen with UV absorptionproperties, which significantly reduces insect damage andprevents incidence of viral diseases, especially TYLCV, intomatoes.

Painting arches white

7 PREPARATION FORNEW CROP

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Soil mulchingSoil mulching with polyethylene sheets is quite commonin the different growing methods, both when growing insoil, as well as in soilless culture in containers.Mulching is an agro-technical activity designed for differentobjectives, which are influenced by the sheet properties:

Mulching with transparent sheets results in heating ofthe upper soil layers and encourages growth, especiallywhen planting is in low temperatures.Mulching with black, silver, or black and white PE issuitable for autumn and spring and prevents germinationof weeds.Co-extruded mulching, which is black on the bottomand white on the top, or one white layer contributes toincreasing radiation by reflection to the plants. Thisis suitable for northern countries where there is littleradiation in the winter.

In general, mulching creates a climate that is suitable forgrowing. When the soil is covered with PE, it has beenfound that irrigation efficiency increases and the rootsystem is more active. Conditions for development of leafdiseases have also been found to decrease, followingimproved microclimate in the greenhouse space byreducing humidity.Mulching is applied over the entire span or in strips overthe beds.With PE mulching, the growers’ awareness of sanitationincreases, and leaves, stems and fruit are easily removedfrom between the rows.The recommended thickness of plastic used for soilmulching is 40-50 micron.The diameter of the holes in the plastic should be 8-12cm. Soil mulching in high temperatures, especially in thehot summer, increases the temperature under the plasticand creates negative and poor conditions for rooting andestablishment of the young plants. In high temperatures,it is recommended to prepare large holes in the mulchingsheets,in order to release the hot air and avoid heating ofthe soil.

Soil sterilizationTomatoes in greenhouses are susceptible to variousdiseases, especially soil-borne diseases. These pathogenscan survive in the soil from one season to the next andmoreover, these inoculates (infecting material) can multiplyin the soil to extreme values. As soon as tomatoes, orany other host plant which is sensitive to these diseases,are planted, they may be damaged by one or morepathogens.Tomato production, which is considered to be expensive,continues over a number of months and there is no croprotation in the greenhouses. Therefore, great effort isinvested to reduce the establishment of pathogens in soilsor growing medium in greenhouses, by performing someform of sterilization as well as by sanitation treatmentsduring and at the end of the season.Here are the main soil-borne pests that may cause damageto the new tomato crop:

13

Fungal diseases: fusarium wilt and verticillium wilt - mostcommercial varieties are resistant to these diseases,however part of them are resistant to nematodes and tocrown root rot (Fusarium oxysporum f.sp. radicis-lycopersici); but there is no resistance available for stemrot (Sclerotinia sclerotiorum), Southern blight (Sclerotiumrolfsii) or Corky root (Pyrenochaeta lycopersici). Since thegenetic sources for resistance to these diseases are limited,they must be control led by soil steri l ization.

Bacterial diseases: bacterial canker (Clavibactercorynebacterium michiganensis) ; bacterial wilt(Pseudomonas corrugate); soft rot (Erwinia carotovora);and southern bacterial wilt (Pseudomonas solanacearum)

Viral diseases: mainly tobacco mosaic virus (TMV).Most varieties are resistant to this disease, except forsome cherry varieties.

Pests: root knot nematode (Meloidogyne spp.), varioussoil-borne or airborne pests, some of which are vectorsfor viral diseases, such as western flower thrips (Frankliniellaoccidentalis)

Parasitic weeds: field dodder (Cuscuta campestris) andbroomrape (Orobanche spp). These weeds are establishedin the soil, propagate by seed and germinate with a suitablehost.Tomato plants are hosts for these parasites, and areseverely damaged when attacked.

Noxious weeds: many types of weeds may reproduceand germinate in tomato production greenhouses, if thereis no suitable soil sterilization.

Soil sterilization methods1. Methyl bromide: This is suitable for control of most

pathogens and noxious weeds in the soil and growingmedium, except for viruses and bacteria. Use of methylbromide is being phased out according to internationalpacts (the Montreal Protocol).

2. Solarization (sun/solar sterilization): Satisfactoryresults have been received with soil solarization insoilless culture. This method is effective in the hotseason.The efficiency of solarization is limited in soils.

3. Metham Sodium: This material is sufficient for controlof various soil fungi and partial control of weeds. It isvery effective in soilless culture for most pathogens.

4. Telodrip inline (Telon with chloropicrin). Thismultipurpose liquid fumigant is applied through thedrip irrigation system and covered with PE film. It isused to control nematodes, fungal soilborne diseasesand certain weeds.

5. Steaming: This method is suitable for control of mostpathogens, including viruses and bacteria. It is suitablefor disinfestations of soilless culture, but is not suitablefor all soils, especially heavy soils.

6. Formalin: This material is suitable for sterilization ofsoil or growing media which have been infested bybacteria.

7. Use of specific pesticides for control of soilbornepests, as well as specific fungicides, nematicides,and herbicides.

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Since innovative sterilization treatments are restricted toa limited amount of pathogens, it is recommended tocombine a number of sterilization methods according toneed. A combination of methods will ensure better resultsthan any separate treatment.Beside the chemical and the physical treatments for soilsterilization it is recommended to exploit the genetic factorto reduce damages of soil-born diseases by introducingthe resistance varieties or the use of rootstock incombination with graftingDetails regarding preparation of soil and sterilizationmethods can be found in the manual “Recommendationsfor Control of Pests in Vegetables”, published in Hebrewby the Agricultural Extension Service of the Ministry ofAgr icu l ture and Rural Development , Israel .

Sterilizing the greenhouse spaceGreenhouses can be sterilized in the summer. After acrop has been removed from a greenhouse, the greenhouseshould be sanitized by solar radiation (solarization) bysealing it hermetically for three to four weeks. Temperaturesin a greenhouse which is sealed in the summer monthsreach values which destroy most pathogens in the spaceand on the frame of the greenhouse. In order to increasethe sensitivity of pathogens to high temperature, it isrecommended to wet the greenhouse interior and soil oncea week by using a 5-10m3/h micro-sprinkler system. Thegreenhouse and soil should be wetted at night or in theearly morning, when temperatures are mild, to preventbursts in the irrigation system. Accessories and equipmentthat are sensitive to high temperatures and which may bedamaged by the heat should be removed before sealingthe greenhouse.The greenhouse is sterilized as part of a comprehensivemethod and a means for sanitation before planting a newcrop.

Preparing the greenhouseBefore planting, the greenhouse is prepared, covered andprotected against tobacco whitefly, which are vectors fortomato yellow leaf curl virus (TYLCV). Covering all thesidewalls with a net keeps these insects out of thegreenhouse. The greenhouse should be hermeticallysealed, especially in the gutter area, to provide maximumprotection against invasion of the pest. A double doorshould be installed at the entrance of each greenhouse,to create a separating passage between the greenhouseand the environment. The greenhouse film coveringshould be thermal IR PE film, with anti-drip additives, bothon the roof as well as on the sidewalls (curtains). Thefilms should have a thickness of at least 0.12 mm (120micron). In many cases, the effectiveness of the additive,which is designed to prevent condensation on the films,lessens in the second season, and therefore it is notrecommended to use the material for more than one year.

14

Covering the soil before sterilization with methyl bromideand other chemicals

Covering beds – soil solarization

Covering the substrate containers – soil solarization

Page 23: O. zaidan tomato production

8In order to reduce the heat load in the greenhouses inthe early season (summer-autumn), various methods canbe applied to improve the climate conditions in thegreenhouses, until a vegetative mass is created which isable to regulate the greenhouse temperatures byevaporation (self-cooling by the plants). These methodsinclude:

1. Evaporative cooling (adiabatic cooling)The principle of evaporative cooling is based on waterevaporation. In this process, the pressure of water vaporin the air increases and the air temperature in thegreenhouse drops. In other words, the sensible heat istransformed into latent heat by capturing the heat in thewater vapor.There are a number of methods for increasing humidity

Double entry in greenhouse

Double entry in net house

IMPROVING CLIMATECONDITIONS INSUMMER ANDAUTUMN

in the greenhouse atmosphere, in addition to humidityresulting from water that evaporates from the plants in thetranspiration process. In recent years, misting and foggingmethods have been developed, joining the wet pad andfan cooling method. The misting and fogging systems aredifferentiated by droplet size. The droplet size has asignificant effect on the process of heat replacement inthe air and the degree that foliage is wetted.When the droplets are smaller, cooling is more effectiveand the leaves are not wetted. In a system with smallerdroplets, the quality of water used for cooling is important,and this should be taken into account when planning thecooling system.

a. Cooling by misting:A misting system for cooling plants is composed of asystem of water lines with low-volume mini-sprinklers (100-250 droplet size), which have anti-drainage valves. Thesystem is usually installed at the height of the crop wireand below the gutter. The mini-sprinklers should be closeenough to each other to wet the entire floor area, withoutoverlapping. The misting system should operate for 0.5-1.0 minutes, every 15-20 minutes during the hot and dryhours. If the system has no control or sensors, operationfrequency and time should be based on the farmer’sexperience. The misting system is switched on and off byan automatic timer and electric valves. The water wetsthe foliage, and cools down the leaves when drying out.This system is effective on hot, dry days, and is suitablefor use with high quality water. Water with a highconcentration of chlorine and sodium may burn and damagethe plants. This cooling method is designed to reduce leafand plant temperatures. The misting system has a marginaleffect only on reducing air temperature.

b. Cooling by pad and fan:This cooling method, which is common in manygreenhouses, has a wet pad on one wall in the greenhouse,with fans on the opposite wall. The fans expel the air fromthe greenhouse, and as a result of the sub-pressure thatis created in the greenhouse, air is drawn from the wetpad on the wall opposite the fans. The cooling pad iscomposed of a special carton block with narrow airpassages over its entire surface. The carton block is wettedwith a large volume of water using a pump system, whichpumps water in a closed cycle. The air, which is drawninto the greenhouse, passes through the wet pad andabsorbs the water vapor. This increases the humidity inthe air and lowers the greenhouse temperature.The disadvantages of this system is that it are veryexpensive, the humidity and temperature in the greenhouseare not uniform, drainage of brackish water is required toprevent clogging in the wet pad, and the plants are at riskif there is a power failure, because the system will notoperated especially in hot summer days, when thegreenhouse is closed. The efficiency of the system dependson the relative humidity outside and the air exchange inand out of the greenhouse.

15

Page 24: O. zaidan tomato production

c. Fogging:This system is based on air vents in the roof, fans on allsides of the greenhouses and nozzles which are installeduniformly around the greenhouse. Water droplets (5 – 25micron) in the form of fog evaporate before reaching theplant. The air, which enters through the roof vents, carriesthe fine water droplets and the water evaporates with theair flow. Water evaporation in the air cools the air in thegreenhouses and lowers the temperature. The advantageof this system is uniform cooling of the entire greenhouse,which enables construction of greenhouses which arelarger than conventional.In this system, evaporation leaves small grains of saltwhich were in the water. These particles may float andmove out of the greenhouse with the air flow, howeversome may sink onto the plants and deposit salt on thefoliage. Care should be taken to prevent this by usingwater with a good quality or water which has been treatedbefore use in the fogging system.

2. Temperature reduction by shading -reducing solar radiation intensity thatpenetrates into the greenhousea. Whitewashing roofs:This is the most conventional technical solution for reducingsolar radiation penetrating into the greenhouse, therebyreducing heat load in the greenhouse. The exterior coveringis sprayed with suitable whitewashing material. It isrecommended to avoid using plaster, which corrodes themetal and damages the film covering.

16

Diagram of a cooling pad and fan system

Wet pad

Fans

Page 25: O. zaidan tomato production

When the white coating is new, it reflects some of theradiation back to the sky, reducing the radiation thatpenetrates into the greenhouse, and lowering thetemperature. If the whitewash is sprayed on the roof inthe spring, when the films are dusty, the color achievedwill be brown, and not white. This color usually absorbsthe radiation and generates heat, while producing excessshading. This combination of lack of radiation and increasedtemperature damages the plant, and therefore it is importantto clean the fi lms before applying whitewash.

b. Shade nets:The radiation intensity and temperature inside thegreenhouse can be reduced by covering the structure witha knitted or woven black shade net. The net is installedabove the gables, without being too close to the filmcovering. The radiation should not be reduced by morethan 20 to 25% of the radiation intensity under a transparentcovering. Shading with this method reduces thetransmission of radiation into the greenhouse, and preventsa drastic rise in temperature inside the greenhouses.

c. Moveable reflective screens:A reflective thermal screen, which is spread out during thehot hours of the day, is another method used to reduceradiation penetrating into the greenhouse. When the screenis completely spread out, it reduces the radiation intensitythat penetrates into the greenhouse and lowers thetemperature. The screen is spread out and closed by asystem of twines installed above the crop wire and belowthe gutters, and operated by a system of motors thatoperate according to thermostats or radiation sensors.This screen is also used to retain heat and save fuel costs,when it is spread out at night in the winter. It reduces heatloss in the greenhouse by blocking escape of infraredradiation (IR).

Whitewashing roofs to reduce solar radiation intensity

17

Shading with shade nets

Moveable reflective screen

Accumulation of dust on greenhouse andnet house coveringsCovering materials accumulate a great amount of dust,due to the static electricity on the covering surface, whichattracts dust particles. Dust accumulation reduces lighttransmission into the greenhouse or net house, whichdamages the yield quantity and quality.Dust starts to accumulate on the covering materialimmediately after it has been spread out. More dustaccumulates in bad weather and when heavy mechanicalequipment operates inside and outside the greenhouses.

Tests show that cleaning the covering films or nets leadsto improved light transmission, resulting in higher yieldsand improved quality.

Cleen insect - proof net

Accumulation of dust - low radiationand limit of ventilation

Page 26: O. zaidan tomato production

9

18

The nets should be cleaned to increase light transmissionand air movement, which improves ventilation inside thegreenhouses. The covering films should be cleaned toimprove light transmission into the greenhouses as well.

Cleaning screens to improve ventilationInsect-proof nets, which are installed on the greenhousewalls and roof vents, accumulate a lot of dust, whichadheres to the screen threads and blocks the holes throughwhich the air enters the greenhouse. In order to improveand increase air passage and ventilation through thescreens, it is important to remove accumulated dustwhenever the screens become clogged.The screens can be washed by spraying water on themfrom the inside of the greenhouse outwards, and from topto bottom. A high-volume sprayer connected to a suitablespraying gun, or a hosepipe with a regulated outlet attachedto a tap, can be used for this purpose, since a high-volumewater spray may damage the screen.

Cleaning film coveringIn the autumn, when the days become shorter and cloudsbegin to gather, dust and lime which is used for shading,should be removed from the film covering in order toincrease the radiation that penetrates into the greenhouse.Postponing this treatment damages the yield quality andquantity. The film covering should be cleaned again duringthe winter in order to ensure that they are transparent, toallow maximum penetration of radiation into the greenhouse.The film covering can be washed with water and a brushfor mechanical separation of dust from the film. Cleaningthe roofs and coverings increases the photosynthesisprocess, resulting in higher yields and improved quality.

Most greenhouse tomato production is dependent uponhybrid varieties. These seeds are developed by breedingspecialists and sold by commercial companies. Theadvantages of hybrid seeds are that they have very highvigor, good uniformity, high production and quality. Diseaseresistances are also bred into these varieties. Growersshould only purchase seeds that have been produced byreputable companies and are properly packaged in sealedpackages. Labeling should include information about thevariety and proper seed storage.The production of a seedling, frequently referred to as atransplant, is an extremely important procedure, as futureplant, growth and fruit production is affected by the characterof the seedling that is produced.Today, most tomatoes for fresh marketing are grown inplugs and rooted in a growing medium, which is usuallyorganic, such as peat, or vermiculite. A good plant isdisease- and pest-free, and has three to five developedleaves. It has a well-developed root system, with a stronghold in the growing medium in the tray cell, so that when

SEEDS, SEEDLINGPREPARATION ANDTRANSPLANTING

these seedlings are removed from the tray in the nurseryand brought to the field for transplanting, the growingmedium remains around the roots.Seedlings that are 3-5 weeks old are considered to beideal, while seedlings over 5 weeks old are less desirable.

Trays with 1.25” to 1.5” cells are used to produce qualitytomato seedlings. The seedlings are produced incommercial nurseries that specialize in seedling production.The farmer orders seedlings for planting in advance.Generally, 25 to 50 days are required from sowing untilsupply, depending on the season and climatic conditions.The seedlings should be planted within 24 hours afterremoval from the nursery. Early transplanting providesbetter conditions for the plants and the future field.Seedlings received from commercial nurseries are packedin cartons and kept in a shaded area that is protected frominsects until they are planted.Tomato plugs are planted in damp soil that has beenirrigated in advance. The seedling’s roots (the plug) shouldbe straight, and not folded when planted in the ground,and covered completely by soil. Air pockets are removedby pressing the soil around the roots with hands or atrowel. The seedlings should be irrigated lightly withinone to two hours after planting. A quality seedling andproper planting guarantee establishment of the seedlingin its new environment, and ensure that growing is notdelayed. If seedlings are planted on a hot day, the plugsshould be dipped in water before planting.

Uniform seedlings produced in a commercial nursery

A seedling that is suitable for planting

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Plant spacing and density –common tomatoesTomato plants in greenhouses are grown in double rows,which enable optimal growing, radiation and ventilationconditions, with wide passages between rows for easyaccess by workers. A distance of 170-185 cm betweenthe double-row centers is required, and the span widthshould be adapted accordingly. Greenhouses that aremarketed in Israel do not have a uniform span width, andthe span width is adapted to the number of double rows.The distance between seedlings in the rows is determinedaccordingly, and should not be less than 40 cm. A highyield is achieved with about 20,000-25,000 plants perhectare. More plants per hectare will not increase theproduction. The fruit will be small and puffy with a poorcolor, and there will be a higher incidence of disease inthe dense conditions.

Table 4. Recommendations for row spacingin greenhouses with varying span width

Estimateddensityper ha.

Plantspacing

Spanwidth

Doublerows

per span

50 cm

40 cm

50 cm

45 cm

50 cm

50 cm

50 cm

40 cm

40 cm

45 cm

22,000

25,000

20,000

23,500

21,000

25,000

22,000

23,000

25,000

22,000

5

4

4

4

4

4

3.5

3

3

3

9 m

8 m

8 m

7.5 m

7.5 m

6.4 m

6.4 m

6.4 m

6 m

6 m

Transplanting young plants in double rows

19

In order to increase the radiation that penetrates betweenthe crop rows and vertical growth, distance between doublerows should be 50-60 cm at the plant base.This distance can be maintained by fixing the horizontalcrop wires at the same distance or even slightly wider, onthe internal greenhouse frame.The best position for the double crop rows is one row oneither side of the gutter poles and the other rows areformed along the span width.This positioning is convenient for agro-technical activities.

The following diagram illustrates distribution ofcrop rows in greenhouses with span widths of7.5, 8.0 and 9.0 m.

Row spacing in different greenhousesand span widths

Enough space between the doublerows allows light penetration

9.0 m 9.0 m 9.0 m 9.0 m

7.5 m 7.5 m 7.5 m7.5 m

8 m 8 m 8 m 8 m

Greenhouse with 9.0 m spans

Greenhouse with 8.0 m spans

Greenhouse with 7.5 m spans

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Tomato plants that are grown in greenhouses are shapedinto one or two main stems by pruning all the sideshoots(suckers) that develop in the leaf buds on the main stem. The height of the crop wires in the greenhouse is plannedaccording to the duration of the harvest season.1. When the harvest season is limited to 3-4 months,

the crop wires should be 2.2-2.5 m high, so that theycan be reached by the workers. When the plant topsreach the crop wire, they are bent in one directionand tied to the central cable with plastic-coated twine.The plant tops are pruned about one month beforethe end of the harvest. Pruning the tops usuallyincreases the fruits’ diameter in the last 3-4inflorescences.With this trellising method, 10-12 inflorescences arepicked from each plant.Planting a short-season variety is common in variouscountries, including the Mediterranean Basin. Thismethod requires lower investment and fewer workdays, and enables planting of another crop in thesame year.

2. When the harvest season is longer than four months,a high crop wire system (at least 3.5 m) should beused. The plant tops are left upright throughout theharvest season. This method enables lowering of thecentral stem by releasing the twine from the hook onthe crop wire. Before lowering the plants, all leaveson the central stem below the ripened or pickedinflorescences should be removed, so that the stemfrom which fruit has been picked lies on the ground.In this method, the work of twisting plants on twineor string, pruning of side branches and other activitiesare performed when the plant tops reach the heightof the crop wire. Therefore, elevated work carts areneeded to reach the high areas. These carts arepropelled forward either by electric motors or bymechanical means such as pedal and chain. Onecart for every 0.2 ha is usually sufficient.

The advantage of this method is that inflorescences withripe fruit that are ready for harvest are at a convenientheight for picking, especially when harvest wagons areused. It is recommended to cut the plants’ tops to stopgrowth about one month before the end of the plannedharvest. In this trellising method, about 20-25 inflorescencesare picked from each plant.

10 TRAININGMETHODS

20

Plant spacing – cherry tomatoesPlant spacing of cherry tomato seedlings for single fruit orcluster harvest are the same as spacing of regular tomatoes.These seedlings are grown in double rows and the distancebetween row centers is 170-185 cm. However, the distancebetween the seedlings varies according to the number ofstems growing on each plant. If there is one stem perplant, the distance between seedlings in the rows is30-40 cm. This is recommended in light and sandy soils. When each plant has two stems, there can be a distanceof 60-80 cm between plants. This is conventional in mediumand heavy soils. The growing method of two stems onone plant is common and conventional when the varietyhas especially large fruit and the aim is to reduce the fruitsize, or when grafted seedlings are used.

Two stems from one plant

Pruning the top branches to encouragedevelopment of two identical stems

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Support for cherry tomato stemsThe inflorescences of cherry tomato plants are large andare not harvested in a shortperiod and at the same time,therefore it is recommended totie cherry tomato stems to asupport system to keep the fruitin inflorescence off the ground.The support system is made ofbent black or galvanized ironrods, with a 6-8 mm diameter, a50-60 cm surface width and a 3-5 cm raised lip on each side toprevent the stems from slidingand falling off the support. Afterinsertion into the ground, thesurface height of the support is40-50 cm. One support isinstalled every 1 meter along therow. In this way, when the plants

40 c

m a

bove

the

surf

ace

20 c

m in

the

soil

4.0

4.0

60 cm

60 c

m

21

Diagram of hooks

Various hooks

are lowered and stems with unpicked fruit rest on thesupports at a height of 40 – 50 cm, the fruit does not touchthe ground. With this method the fruit is free of sand anddoes not rot as a result of contact with the damp ground.

Training equipmentOne plastic or metal hook for each plant is used in highcrop wire training. The hooks are wrapped with 8-10 m ofplastic twine (recommended 900 m/kg). Twine from theprevious crop should not be used, as it may carry viraldisease or tear as a result of wear. New twine is attachedto the hooks for each new crop.With low crop wires, the same type of twine is used withouthooks and tied to the crop wires which are at a height ofabout 2.5 m.In both methods, the plants are tied to the crop wire byforming a loose ring around the central stem or by attachingthe twine to the plants with plastic clips. The plants arewrapped around the twine about once every 7-10 days,

Diagram of supporter

Cherry tomato plants with and without supports

Page 30: O. zaidan tomato production

depending on the temperature and the plant’s growth rate.The clips can also be used to attach the stems to the twineduring growth, which eliminates the need for wrapping theplants around the twine, and significantly reduces breakingof the plant crowns. When tying the twine to the plants,the knot or hook on the trellising cable should be movedsideways by at least 50 cm from the center of the plant,so that the plant grows at an angle towards the row, witheach row leaning in the opposite direction.This determines the direction of the plants when lowered,and the plant leans towards the row and not towards thework passages.

22

Inserting the twine into the stem

Tying clip and inflorescence support

Pruning suckers or side-shootsIn order to shape the plant into one central stem, all theside-shoots growing near the leaves should be prunedthroughout the growth period. The side-shoots are prunedwhen they are less than 5 cm long and removed from thebase without leaving any remnants on the central stem.Late pruning leaves a wound which does not dry outquickly, and is susceptible to penetration of bacterialdiseases and Botrytis. Side-shoots which are not prunedin time use nutrients and assimilates from the central stemand damage proper development of the plants. The cutbranches and leaves should be collected into containersand removed from the greenhouse on the same day.If a crop with two stems on one plant is planned, as isconventional with cherry tomatoes and grafted plants, thefirst secondary branch under the first inflorescence shouldbe left, or a plant with two stems should be purchasedfrom the nursery.

Removing leavesOld and yellowed leaves are removed after they havecompleted their function of photosynthesis. Lower leavesare removed to increase ventilation close to the ground.Leaves can be first removed when the plants reach aheight of 1-1.5 m and produce 5-6 inflorescences. At thisstage, 2- 3 lower leaves, which have limited efficiency andtouch the ground, are removed. Leaves are removedagain when the fruit in the first inflorescence is picked.All the leaves below the inflorescence are removed. Whenfruit in another inflorescence is picked, all the leaves belowthat inflorescence are removed. Leaves above theinflorescence with unripe fruit are not removed. Inindeterminate tomato plants, movement of assimilate fromthe leaves to the fruit is generally characterized by transitionof assimilates from one leaf below the inflorescence andanother two leaves above that inflorescence. Therefore,it is important not to remove leaves above or belowinflorescences where the fruit has not yet ripened. It isrecommended to remove leaves on a clear and dry day.If leaves are removed on rainy or humid days, pesticideshould be sprayed at the end of the process, especiallywith copper materials, to prevent bacterial disease.

Sunburn as a result of over exposure to radiation

Plastic clips and cluster supporter

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23

Excessive removalof leaves

Controlled removalof leaves

The leaves have many tasks apart from supplying nutrientsto the fruit:In summer, they provide shade for the green fruit andprevent sunburn or development of fruit with greenshoulders. In winter, the leaves protect the fruit againstchill by preventing heat radiation from the fruit to thegreenhouse atmosphere.Moderating the temperature change of the fruit reducesthe risk of fruit cracking, especially in autumn. Whenremoving leaves, they should be broken off at the base,close to the central stem, without leaving stubs or parts ofthe leafstalk on the stem. The leaves are removed byholding the leafstalk close to the stem in one hand, andthe plant in the other hand. The leaf is moved upwardsand downwards until it is detached from the stem. Anabscission layer (scar) forms where the leaf is removed,resulting in quick drying of the wound. However, when thestalk is not cut close to the stem, stubs are left. The wounddoes not dry out and it constitutes a source for penetrationof pathogens.

Movement of assimilates

Supporting clustersIn stress conditions, especially where there is lack ofradiation, the cluster stems close to the plant’s centralstem bend. This interferes with the movement of assimilatesto the fruit in the cluster, and in extreme cases it causescomplete abscission of the inflorescence from the stem,reducing yield and quality. Therefore, when there is anindication of this, it is recommended to install supports forthe clusters. Increased radiation transmission betweenplants in the rows and between the row pairs reducesdamage.

Tomato clusters witha bent stem

Cherry tomato clustersLeft: A bent stem –defective colorRight: Straight stem –normal color

In order to achieve a high quality and quantity yield,tomatoes should be planted in mild climatic conditions,which are suitable for flowering and fruit set (see sectionthat discusses climatic factors and their influence on tomatoplants). Therefore, tomatoes should not be planted whenclimatic conditions develop to extreme temperaturecombinations. Temperatures that are higher than 32ºC inthe day and 22ºC at night or lower than 18ºC in the dayand 10ºC at night are considered to be detrimental to thetomato plant and disrupt the flowering and fruit setprocesses. The plants’ development rate and propertiesare also damaged. In high temperatures, the plants developlong and sparse internodes. In low temperatures, theplants develop short and dense internodes.Tomatoes can be planted in greenhouses in differentseasons, and planting can be planned according to areas,required harvest period and required duration of yield.In Israel and countries with a similar climate, tomatoescan be planted at the end of summer. The crop can beharvested from the beginning of winter until mid-summer.

11 PLANTINGSEASONS

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24

In this way, high yields can be achieved, which justify theinvestments and various agro-technical treatments suchas the continuous plant twisting and sucker removal.Although tomatoes can be planted in other periods, andin fact, almost year round, the yield periods are short andthe yields level are lower compared to those received whenplanting in the optimum period.There may be various problems in the plants’ fertility insome planting periods, especially in summer, due totemperatures that rise to harmful values. Experienceshows that planting in June and July is considered to beproblematic, and the chances of receiving normative yieldsin this period are slight.In very hot regions, where both day and night temperaturesare very high, it is not recommended to plant tomatoesfrom the end of spring until the end of summer. The PEfilms covering greenhouse roofs and the insect proof netson sidewalls also raise temperatures to extreme and harmfulvalues. In cold regions, it is not recommended to planttomatoes in the winter, as plants may be damaged by thelow temperature. However, if the greenhouse is equippedwith a heater which operates in the winter (low temperature),tomatoes may also be planted in the cold months.Double-crop production is common in many regions. Thismethod enables production of a high quality and quantityyield, without the need to invest in the equipment and laborused when growing with high crop wires. The disadvantageof the double-crop method is that production is notcontinuous and yields tend to be lower. This method issuitable where there are many greenhouses and productionand marketing times need to be flexible.The period from planting until harvest is influenced by thevariety, planting date and climatic conditions in the region.In the hot season, harvest of early ripening varieties shouldstart after 60 to 65 days, and harvest of late ripeningvarieties should start after 75 to 85 days. However, whenplanting in the cold season, early ripening varieties areharvested after 100 days, while late ripening varietiesrequire about 120 days until harvest.

Lake of fertility (high temperature)

Collapse of the locules (low temperature)

12Indeterminate varieties, which are suitable for growing ingreenhouses, are grown on one central stem bycontinuously pruning the sideshoots. Researchers areworking to introduce favorable attributes related to fruitquality and disease-resistance. Varieties are selectedafter they have been studied in pilot plots, covering differentseasons and regions. The tests include yield level, fruitquality, compatibility to local and export market demandsand to different growing conditions. Great success hasbeen achieved by breeding varieties that are suitable forgrowing in greenhouses and which are resistant to soilbornediseases carried by fungi and nematodes.Effort has been invested in breeding varieties that areresistant to viral diseases, especially TYLCV, which iscarried by Bemisia tabaci (whitefly).If TYLCV-resistant tomato varieties with good yields andquality are developed, nets with a mesh density less than50 mesh can be used. This will lead to improved climateinside the greenhouses by increasing passive ventilation.

TABLE TOMATOVARIETIES

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25

Medium

Very Good

Very Good

Medium

Medium/good

Good

Very Good

Good

Good

Very Good

Medium/Good

Medium/Good

VeryGood

Good

Good

VeryGood

Good

Good

Good

Good

Flattenedglobe

Flattenedglobe

Flattenedglobe

Globe

Flattenedglobe

Globe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Globe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

ColorShapeVariety Resistance

DanielaR-144

Shirley

AnathFA-189

Nur259

DominiqueFA-593

Philippos

AbigailFA-870

Graziella

Cassius

Astona

Gironda

Trofeo

CharlotteFA-1402

Shannon

NeelyFA-1410

Rosaliya

HT 1141

770-Sandrin

Bonarda

9934-Mali

Firmness Plantingseason

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 N Tm

V F1 F2 N Tm

V F1 F2 N Tm

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 N Tm

V F1 F2 NTm

V F1 F2 Fr NTm

V F1 F2 Fr NTm

V F1 F2 Fr NTm

V F1 F2 Tm

V F1 F2 Fr NTm

V F1 F2 Tm

V F1 F2 NTm

Good

Good

Good

Good

Good

Good

Good

Good

Good

Good

Good

Good

VeryGood

Good

VeryGood

Good

Good

Good

Good

Good

Autumn/Spring

Autumn/Spring

Summer/Spring

Autumn/Spring

Autumn/Spring

Autumn/Spring

Autumn/Spring

Spring

Spring

Autumn/Winter

Autumn/Spring

Autumn

Autumn/Spring

Autumn/Winter

Autumn

Summer/autumn

Summer/Spring

Summer

Spring/Summer

Summer

Vigor

Strong

Medium

Strong

Medium/Strong

Strong

Medium

VeryStrong

Strong

Strong

Strong

Strong

Strong

Strong

VeryStrong

VeryStrong

Medium

Strong

Strong

Medium

Strong

Table 5. Common single-harvest tomato varieties and different growing seasons

The following tables present information about varieties that are suitable for growing in greenhouses andnethouses. The varieties in the table are recommended for planting in Israel, and may also be suitablefor planting in Mediterranean countries, North Africa, Latin America and other countries with similar climaticconditions.

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26

ColorShapeVariety Resistance Firmness Plantingseason

Vigor

Good

Good

Good

Good

Good

Very Good

Medium/good

Medium/good

Medium/good

Good

Good

Good

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Flattenedglobe

Globe

Flattenedglobe

Largeglobe

Flattenedglobe

MeitarFA-1907

MichaellaFA-1903

MelissaFA-1415

Nemoneta

Natalya

Bonaque

ColetteHA-832

HA-3209

DRW-6478

Minhir

BrillanteFA-179

NerissaFA-1420

V F1 F2 NTm

V F1 F2 Fr NTm

V F1 F2 Fr NTm

V F1 F2 NTm

V F1 F2 NTm

V F1 F2 NTm

V F1 F2 Tm

V F1 F2 NTm Ty

V F1 F2 NTm Ty

V F1 F2 NTm

V F1 F2 Tm

V F1 F2 Fr NTm

Good

Good

Good

Good

Good

Good

Good

Good

Good

Good

Medium

Good

Summer/autumn

Autumn

Spring

Autumn

Autumn

Autumn/Spring

Autumn/Spring

Autumn

Autumn

Autumn/Spring

Autumn/Spring

Spring/Summer

Strong

Medium/Strong

Strong

Strong

Strong

Strong

Strong

Strong

Strong

Medium/Strong

Medium

Medium

Table 5. Continuation

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For example, Spain is considered to be a large vegetableproducer, particularly of tomatoes.Tomatoes are produced year round for local and exportmarkets. Production areas are distributed in differentregions, including the mainland and Canary Islands. Spanishtomato production is characterized by its wide range ofcolors, sizes and shapes.

Main varieties for different market segments in Spain:Cluster harvest: Pitenza, Ikram, Durinta.Single red fruit: Daniela, Jamile, Boludo, Kampala,Doroty, Eldiez, Bombay, BrillanteBreaking color (Pinton): Isabella, Carolina, Tyrade,Caramba, Rafter, Raferty, Rambo, Salvador, Lido, ZinacSpecialty: Patrona, Realeza, Evaluna, Cencara, Reva,MiriadeCherry tomatoes for single and cluster harvest:Alina, Conchita, Josefina, Karmina, Katalina, Natacha,Lupita, Salome, Shiren, Zarina.

Resistance Code:Key to characterizing and identifying tomato varieties’resistance and tolerance to pests:

F1: Fusarium oxysporum f. sp. Lycopersici - race 1F2: Fusarium oxysporum f. sp. Lycopersici race 2V: Verticillium dahliaeFr, Cr: Fusarium oxysporum f.sp. radicis lycopersici

crown and root rotP, K: Pyrenochaeta lycopersic i - Corky rootN: Root-knot nematode - Meloidogyne sp.Tm: Tobacco mosaic virusTy: Tomato yellow leaf curl virusC: Leaf mold - Cladosporium fulvum-Fulvia FulvaWi: Silver leafSw: Tomato spotted wilt virus (TSWV)Pto: Bacterial speckLt: Powdery mildew

Many local and international breeding teams are involvedin the intensive activities surrounding breeding of tomatovarieties. It can be assumed that the list of varieties maychange according to progress of the breeding process.New varieties are usually selected because they havebetter yield, quality and resistances than the conventionalvarieties that are used.

Cherry tomatoes are one of the tomato products that aregrown in Israel and targeted for the local market as wellas for US and European markets. Cherry tomato productionis also common in many other countries. Production hasexpanded in recent years, because of longer shelf life andbetter taste.

Single cherry tomato Cherry tomato clusters

Cherry tomatoes in full bloom

These tomatoes are characterized by round fruit, high-quality taste and long shelf-life. Cherry tomatoes areproduced throughout the year, mostly in greenhouses andnet-houses, with a small percentage produced in openfields.The optimal diameter of cherry tomatoes is in the rangeof 18 to 30 mm, however fruit with a 30 to 35 mm diameteris also marketed, although on a smaller scope and tospecial markets.The cherry tomato is sorted into groups according todiameter and packed in different packages, according tothe buyers’ requirements. Cherry tomatoes can be grownfor cluster harvest. These are special varieties which haveclusters with symmetrical shapes, uniform fruit size anduniform ripening.In cluster cherry tomatoes the fruits are connectedsymmetrically, in a fishbone shape, to both sides of theinflorescence and create a cluster with 8 to 12 fruits.

13 CHERRYTOMATOVARIETIES

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Cherry tomato clusters before harvest Defective fertility in cherry tomatoes - high temperature

Table 6. Common cherry tomato varietiesfor greenhouse production

Cluster harvest

S ing le harvest

Var ie ty Resistance

-

VF1 Tm

F N Tm

F N Tm

V F1 Tm Pto

V F1 F2 Tm

F1 N Tm C5

V F1 F2 Fr N Tm Pto

V F1 F2 Fr N Tm Pto

Josef ina R-139

Bambino

Zarina

Natacha

Dominion DRC-316

Damita FA-1392

Katalina

Alina

Karmina

V F

VF Tm

Naomi R-124

Camellia R-819V F1 F2 Fr Tm C5 Wi

F1 F2 N Tm

F1 N Tm C5

F1 Tm

V F1 Tm Pto

V F1 F2 N Tm Ty C5

Conchita

Shiren Fa-1335

Rubino Top

Victories

Diamante

TyTy (C1002-20)

Planting periods for cherry tomatoesPlanting periods for cherry tomatoes are directly influencedby supply and marketing agreements which are determinedbetween the grower and exporter and of course by theclimatic conditions in the region.

Similar to regular tomatoes, cherry tomatoes are alsosensitive to extreme temperatures, both high and low.The planting season should be planned so that most ofthe growing, flowering and fruit set take place when thereare no continuous extreme temperatures. Under extremeclimatic conditions, there may be disruptions in the plants’fertility, inflorescence shape and flower size, and theflowers’ fertility may be defective.

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Marketing of vine ripened cluster tomatoes has recentlyexpanded in many countries. This innovative product ismarketed through a marketing channel which suppliestomatoes with a fresh appearance: fruit on a cluster withthe green cluster stem and calyx being hallmark signs ofrecently harvested fruit and thus freshness. Varieties thatare suitable for cluster harvesting must have a stem andcalyx that remain green and fresh for a long time andprevent the fruit from dropping off the cluster duringtransportation.All tomato varieties have fruit which grow on a truss/cluster;

14 GROWINGTOMATOES FORCLUSTERHARVESTING

29

Clusters: green and ready for harvest

Cluster tomatoes

however varieties that are suitable for cluster harvest havea central axis with the fruit attached symmetrically in afishbone shape. Tomatoes that are harvested in clusterscan be characterized and classified into groups by the fruitsize and diameter of the fruit on the cluster. Each grouphas varieties which meet different marketing requirements.

Groups according to fruit diameter:1. Regular tomatoes: fruit with a 55 to 75 mm diameter,

4 to 6 fruits per cluster.2. Cocktail/baby tomatoes: fruit with a 35 to 55 mm

diameter, 5 to 8 fruits per cluster.3. Cherry tomatoes: fruits with a 20 to 35 mm diameter,

8 to 12 fruits per cluster.

The chance of receiving a good cluster/truss, which isuniform in size, shape, color and firmness, depends onvarieties which are able to flower and ripen fully in arelatively short time between opening of the first and lastflowers in the inflorescence. Five to seven days isconventional for full flowering. This enables productionof a quality cluster with uniform ripening.

Production of clusters with high quality and uniform fruitrequires suitable and stable climatic conditions through-out the growing period. Changes in climatic conditions,especially in temperature, have a decisive influence onthe character and shape of the clusters that develop.

Cluster shapingUniformity of the fruit size in the inflorescence is achievedby agro-technical treatments applied throughout the growingperiod. These treatments include removal of the firstflower, when this flower is too large or clearly deformed.This is conventional in varieties that are targeted for clusterharvesting and which have particularly large fruit. Pruningthe last flowers in the inflorescence, after fruit set of aminimal number of fruit, is required according to the groups,which were defined by fruit diameter. This is conventionalin varieties with a large number of flowers in theinflorescence, especially cherry varieties.

Planting dates for cluster harvestingVarieties which are designated for cluster harvest shouldbe planted when the climatic conditions are good for fruitset from the first inflorescence, so that fruit set is notdamaged by high summer temperatures. Unsatisfactoryfruit set and ripening results in non-uniform clusters whichare not suitable for marketing as cluster tomatoes. It isrecommended to strive for the optimal planting time indifferent areas, in order to achieve perfect ripeningbeginning with the first cluster. In winter, it is recommendedto operate a heating system in greenhouses for bothagronomical and economical aspects:

Production of a normal inflorescenceUniform flowering and fruit-set rate in the inflorescenceUniform ripening of the fruit in the clusterIncrease of yield by accelerating the fruit’s ripeningrateIncrease in the number of clusters that are picked

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Following the market’s saturation with regular tomatoes,new tomato products are being developed, which aredesignated for local and export markets. Development isconducted in different, parallel and similar paths, from theaspect of the goals and objectives. Developing newproducts involves professional agro-technical investment,as well as development of special markets, which means

Cocktail tomato cluster, 35-50 mm

Plum tomatoes

Midi-plum tomatoes

Mini-plum tomatoes

Table 7. Tomato varieties suitable forharvesting in clusters

Var ie ty CommentsResistance

Symmetrical cluster,medium-sized fruit, goodfirmness, medium color

V F1 F2 N TmPrincess- AB 2536

Symmetrical cluster,medium-sized fruit, goodf i rmness and color.Requires special varietytreatments - sensitive tomicroelement deficit.

V F1 F2 TmDorinta

Symmetr ical c luster,medium/large-sized fruit,good firmness, mediumcolor, suitable for growingin brackish conditions.

V F1 F2 N TmDominiqueFA-593

Symmetr ical c luster,medium/large-sized fruit,good firmness, mediumcolor, suitable for growingin brackish conditions

V F1 F2 TmDaniella-R 144

Symmetrical cluster, 5-6fruits in cluster, goodfirmness and color,medium-sized

F1 F2 N TmIkram

Symmetr ica l c luster,globe, 5-7 fruits in cluster,good color, medium-sized

V F1 F2 Fr NTm C5

Risoka

Symmetrical cluster, 6-8fruits in cluster, mediumcolor and medium-sized

V F1 F2 TmPetenza

Symmetrical cluster, 5-7fruits in cluster medium-sized

V F1 F2 TmFH-1476

Symmetrical cluster,medium sized fruit, 6-8fruits in cluster medium-sized

V F1 F2 TmFA-62203

Symmetr ical c luster,globe,good color, relativelysmall-medium size of fruits

V F1 TmR-62202

15 NEW TOMATOPRODUCTS

changes in consumer behavior and the acceptance of thenew products as something new and innovative and notsimply an alternative to tomatoes. The production andmarketing of the new products demands perseveranceand professionalism because of the time it takes for themarket to absorb new products.Main properties of the new products: Unconventional shape and color Consumed in smaller amounts High value and returns

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Colorful cluster tomatoes

Development of the new product requiresthe following:

Definition and characterization of the productAgro-technical developmentMarket developmentPenetration of product

New products include:Deep globe tomatoes: with different colors and sizes,such as plum, midi-plum and mini-plumColorful tomatoes: orange or yellow, as well as theconventional and common red. Can be grown forsingle or cluster harvest.Flavor tomatoes: with especially high TSS and sugarlevel. Different sizes, deep globe or globe. Can begrown for single or cluster harvest.Beef tomatoes: large tomatoes, which are flat and havea diameter of over 82 mm. When the fruit is cut in half,its fleshiness and large number of locules are apparent.Tomatoes with special nutritional value or with highlevels of lycopene or β carotene, which are known tohave special medical value.

Colorful deep globe tomatoes

Orange cherry tomatoes

Single colorful tomatoes

Yellow cherry tomatoes

Flat beef tomatoes

Aranka tomatoes

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Cencara-deep globe fruit

32

Italdor-very deep globe fruit

Mix of tomato products

Mini-plum packed for export

Regular tomatoes

Yellow and red cherry tomatoes

Cherry tomato Cluster

Marinda (Marmande type)

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Table 8. Varieties of special tomatoes (Different Products)

Single/cluster

Variety Features

Goldita DRC-89 Yellow, globe cherry

FA-1339 Yellow, globe cherry

Drk-941 deep globe cocktail, deep red with green stripes

OrangenoDRC-1039

Orange, Mini plumDrk-927

Orange, globe cocktail

Melody AB-8061 Mini-plum deep globe cherry

DRC-353 Mini-plum deep globe cherry

DRC-377 Mini-plumHA-4801 Mini-plumHA-1331 Mini-plum

FA-1328 Mini-plumRevello Mini-plum - mini S. MarzanoFA-654 Deep globe midi-plum

Columbus-RZ Deep globe midi-plumFlavorinoDRC-186

Deep globe midi-plum

NR-8387 Midi-plum98-AB-550 Deep globe plumFA-1413 Deep globe plum

Romana Deep globe plum

FA-62201 Deep globe plumFA-1463 Deep globe plum

Ovata-RZ Deep globe plum

Pisa Deep globe plumCencara Deep globe plum

Oscar

Italdor Long plum, S. Marzano typeAranka Medium cocktail, globe

RosalindeFA-631

Large cocktail, globe

FA-643 Large cocktail, flattened globe

Baby MayaFA-646

Medium cocktail, globe

FA-612 Globe cocktail

Single

Harvest

Single

Single

Single

Cluster

SingleSingleSingleClusterSingle

Single/clusterSingle/clusterSingle

SingleSingle/cluster

Single/clusterSingleSingle

Single

SingleSingle

Single/cluster

Single/clusterSingle

Single

SingleCluster

Cluster

Cluster

Cluster

Single

Resistance

Tm C5

V F1 Tm

V N Tm

V F1 F2 Tm

V F1 F2 Tm C5

V F1 N Tm

V F1 F2 N TmV F1 F2 Tm C5

V F1 F2 Tm PtoV F1 N Tm

F TmV F1 Fr N Tm PtoV F1 F2 Tm

V F1 F2 Fr Tm C5

V F1 F2 N Tm

V F1 F2 N TmV F1 F2 N TmV F1 F2 Tm

V F1 F2 N Tm Lt

V F1 N TmV F1 Tm

V F1 F2 N Tm

V F1 F2 N TmV F1 N Tm C3

V F1 F2 Fr N Tm C5

V F1 N TmV F1 F2 Tm C5 Wi

V F1 F2 Tm

V F1 F2 Tm

V F1 F2 Fr N Tm

V F1 F2 Tm

DRK 903 V F1 F2 Tm Orange, medium size

Marinda V F1 Tm Marmande type, flattened rib Single/cluster

33

Long plum, S. Marzano type

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34

16 PARTIAL RESISTANCETO ROOT KNOTNEMATODES

There are many types of nematodes that cause damageto tomatoes. The most common type is the root knotnematode (Meloidogyne spp.), which causes a diseasethat is recognized by swollen nodules on the plant roots.Nematode infestation severely damages the plants, causinglack of absorption of water and nutrients. The plants becomeweak and the yield is low. In severe infestation, the knotson the roots multiply, until absorption of water and nutrientsstops completely and the plants wilt and die.There are four common types of Meloidogyne spp.nematodes: M. Javanica, M. Incognita, M. Arenaria andM. Hapla.Today, tomato varieties which are resistant to root knotnematodes contain the MI gene. This gene providesresistance to M. Javanica, M. Incognita and M. Arenariaspecies, but not to M. Hapla species. The resistanceprovided by the MI gene breaks down in soil temperaturesabove 27-28ºC, causing heavy damage to the plants,sometimes to the extent of collapse and wilting. If a farmerplans to plant a nematode-resistant variety in greenhousesduring the hot season, it is recommended to apply allpossible means to ensure that the soil (or growing medium)temperature does not exceed 27-28ºC. If the soil is infestedwith nematodes, it is recommended to sterilize beforeplanting, applying one of the methods that reduces thenematode population.Resistant plants develop small knots on the roots, evenwhen the soil temperature is not high. This may occur inresistant plants that are heterozygous around the MI gene(contain only one copy of the gene in each cell). In thiscase, the resistance does not break down and the plantscontinue to develop normally, without any damage to yieldlevel, despite the appearance of small knots on the roots.

Diagram of nematode symptoms in various plants

Right: resistant variety; left: sensitive variety

Propagation by grafting is a well-known and conventionalmethod used in orchard and rose crops. Over the lastseveral years, grafting has been introduced in vegetables.

In this method, a scion of a variety or cultivar, which iscapable of producing a quality commercial yield, is graftedonto rootstock which is capable of growing in harsh soilconditions. These adverse conditions include soil infestedwith nematodes and soilborne diseases, lack of aeration,high salinity and other problems. In this way, a susceptiblevariety/cultivar can be grown in soil which was previouslyunsuitable, achieving commercial yields.Propagation by grafting has become conventional invegetables, especially tomatoes, and it serves as a meansto control soil problems, such as root diseases. In somecases, it was found that the grafted plant develops greatervegetative growth as compared to a regular plant. Thepossibility of growing two stems on each grafted plant isbeing examined. This will reduce plant density and ofcourse save the grower money.Tomato rootstock varieties have a wide range of resistanceto soilborne diseases. The grafting method can thereforereduce the need to sanitize soil with every planting.Moreover, the use of methyl bromide can be dramaticallyreduced and even eliminated as grafted varieties, togetherwith a range of new chemicals to control soil diseases,are used.

17 ROOTSTOCKAND GRAFTING

Grafted plants

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35

Growing three branches froma grafted plant (cherry tomatoes)

Growing two branches froma grafted plant (regular tomatoes)

Grafted plants -attachedby plastic clips

Generally the rootstock is a hybrid plant, as a result ofcross breeding of wild species such as Lycopersiconhirsutum with the cultivated type Lycopersicon esculentum.The combination of the two types is the main factorinfluencing the vigor and strength of the rootstock and thegrafted plants.

Advantages of grafting: Resistant rootstock is widely available Wide resistance range for soilborne diseases Strong vegetative growth and reduced plant stress Methyl bromide substitute Reduced need for crop rotation

Disadvantages of grafting: High production cost Risk of disease infection during grafting Investment in expensive mechanization Limited production capacity in nurseries Risk of incompatibility between scion and rootstock

Success in grafting tomato plants requires know-how andskill in performing the process, and especially in determiningthe suitable planting depth in the field so as to prevent the

risk of adventitious roots from the scion, which maypenetrate into the soil and take root. If such a root systemdevelops, the scion may be infected by a soilborne pathogento which it is susceptible.

Transplanting ofgrafted plant

Grafted seedling

Incompatibility / compatibility

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35

Growing three branches froma grafted plant (cherry tomatoes)

Growing two branches froma grafted plant (regular tomatoes)

Grafted plants -attachedby plastic clips

Generally the rootstock is a hybrid plant, as a result ofcross breeding of wild species such as Lycopersiconhirsutum with the cultivated type Lycopersicon esculentum.The combination of the two types is the main factorinfluencing the vigor and strength of the rootstock and thegrafted plants.

Advantages of grafting: Resistant rootstock is widely available Wide resistance range for soilborne diseases Strong vegetative growth and reduced plant stress Methyl bromide substitute Reduced need for crop rotation

Disadvantages of grafting: High production cost Risk of disease infection during grafting Investment in expensive mechanization Limited production capacity in nurseries Risk of incompatibility between scion and rootstock

Success in grafting tomato plants requires know-how andskill in performing the process, and especially in determiningthe suitable planting depth in the field so as to prevent the

risk of adventitious roots from the scion, which maypenetrate into the soil and take root. If such a root systemdevelops, the scion may be infected by a soilborne pathogento which it is susceptible.

Transplanting ofgrafted plant

Grafted seedling

Incompatibility / compatibility

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36

Scion roots infected by nematode

Table 9. Resistance of common andexperimental rootstock suitable forgrafting of different tomato varieties

Rootstock CompanyResistance

BEAUFORT

ENERGY

HE-MAN

UNIGENE

AX-105

MAXIFORT

W-393

6153

6776

SUKKETO

RESISTAR - 4402

SPIRIT

TRIOFORT – 217

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm

V F1 F2 Fr N K

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm C5

V F1 F2 Fr N Tm C5

V F1 F2 Fr N K Tm

V F1 F2 Fr N K Tm

V F1 F2 Fr N K (partly) Pto Tm

V F1 F2 F3 Fr N Pto Tm

DERUITER

VILMORIN

S&G

UNITED-GENETIC

AGROTIP

DERUITER

WESTERN SEEDS

RIJK ZWAAN

BRUINSMA

KANEKO SEED

HAZERA

NUNHEMS

A.B - SEEDS

Resistance data on varieties and rootstocks inTables 5-9 was submitted by the seed companies

Tomato flowers contain both male parts (stamens andpollen grains) and female parts (ovaries, ovules, stylesand stigma). In most cases, the flowers are self pollinated.However sometimes there is cross pollination, especiallyby insects. After the flower buds open, the pollen chambersopen and pollen spills onto the stigma. The pollen grainsstick to the style, and reach the ovaries and ovules, wherefertilization takes place. After the ovules are fertilized theybecome seeds and the fertilized ovule starts to grow and

develop until its final size. The fruit size and shape areinfluenced by the number of seeds which develop insideit. A flower that has been fertilized with a good quantityof pollen may produce fruit with a shape and size that arecompatible with the variety, while a partially fertilized flowermay produce irregular and small fruit, since it containsfewer seeds.In open-field production under optimal growing conditions,there is cross and self-pollination in the tomato flowers.The natural wind improves the propagation process andencourages the opening of the pollen chambers and spillingof pollen. In plants which are grown in greenhouses, self-pollination is often only partial and insufficient to producea good yield. Therefore various methods are applied toassist the pollination process.

18 POLLINATIONAND FRUIT SET OFGREENHOUSETOMATOES

Methods to improve pollination ingreenhouses

Vibrator (electric bee): A battery-operated device witha vibrating unit at the end touches the inflorescencestem, vibrating the flowers. The pollen grains arereleased from the stamen and fall onto the stigma.Air pulsator: A motorized backpack sprayer with anair-blast unit shakes the plants. The air currentsrelease the pollen grains.Bumblebees: The bumblebee is attracted to the tomatoflowers which do not have nectar and collects pollengrains from the flowers. Common honeybees are onlyattracted to flowers with nectar.Use of bumblebees has become the most commonmethod for pol l inat ion of tomato f lowers.Details of this method appear later on in this booklet.

A vibrator or air pulse is applied every one to two days,in the late morning after humidity in the greenhouse hasdropped and the flowers are dry. When wet flowers areshaken, the pollen is not released properly, resulting indefective fertility. The tip of the electric bee is placed ontothe inflorescent stem and operated for one or two seconds.The entire inflorescence is shaken and the flowers arepollinated. Tomato flowers do not open up together,therefore the process should be repeated whenever thereare new open flowers in the inflorescence.

Small fruit as a result of faulty pollination

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3 7

Shaking an inflorescence with an electric vibrator

Flowers and fruit of different ages in an inflorescence

Table 10. The influence of climaticconditions on the number of pollen grainsof the stigma after vibrating

Comment: Estimated average number of pollen grainsper flower: 76,000

Time 08:00

Air temperature

Relative humidity

No. of pollen grainson stigma

10ºC

95%

225

10:00

16ºC

81%

375

12:00

19ºC

70%

450

Table no. 11: Improved yield perplant with different treatments ingreenhouses – Angela variety(according to Rilska I.)

Use of growth hormones for fruit set

In extreme temperature conditions, when it is either veryhot or very cold, and there is no pollen in the flowers forthree consecutive days, bees or vibrating will not beeffective. In this case, it is recommended to use growthhormones to improve fruit set. The hormones should besprayed onto the inflorescence only, and not onto the planttops. The materials recommended for use belong to theß- naphthoxy acetic acids. These hormones enable divisionand growing of cells in tomato plants without the need forthe pollination process. Fruit formed after spraying withgrowth hormones are usually seedless. The hormonesare sprayed with the concentration that is recommendedby the manufacturer, as it appears on the label, and witha spraying volume of 70 to 100 l/ha in each spraying cycle.Excessive use of hormones should be avoided as thismay increase fruit puffiness. Each inflorescence is sprayedtwice. The first spray is when three or four flowers haveopened in the inflorescence, and the second spray is whena new inflorescence has developed, also with three or fouropen flowers. From this point, the first spray is on thenew inflorescence, and the second is on the previousinflorescence, and so on. This method ensures that eachinflorescence is sprayed twice only, since not all the flowersin the inflorescence open together. The second sprayingis necessary, since it ensures full fruit set in all the flowersin the inflorescence.

TreatmentAveragefruitweight(g)

Fruitweightper plant(kg)

5.32

4.86

4.17

3.72

43

21

6

... . . .

89

83

77

72

24

15

7

.......

Vibrating witha vibrator

Vibrating with airpulse

Spraying withhormones

Control

Improvem

ent(%

)

Improvem

ent(%

)

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38

Spraying flowers with growth hormones

Hollow fruit resulting from a highconcentration of growth hormones

Distorted foliage resulting from a highconcentration of growth hormones

Hormonal fruit set without side effects

Blossoms which remain vital aftertreatment with growth hormones

Note:In many cases it has been observed that following sprayingwith hormones, the petals remain close to the fruit andbelow the sepal. In high humidity, the petals are susceptibleto pathogenic fungi, mainly Botrytis and Rhizopus. Thesefungi create a fuzzy mat of spores and mycelium whichdevelop rapidly and result in fruit rot and great damage.

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Pollinating services: A standard bumblebee hive contains one queen anddozens of workers, larvae and eggs. One hive is suitablefor pollinating about 0.2 to 0.25 hectares of greenhousesfor five to eight weeks. The first hive that is installedconstitutes the basic population, after which other hivesare introduced, or old hives are replaced with new ones.Cherry tomato varieties have a large number of flowersand therefore, there should be twice as many hives perunit than in regular varieties.The petals of the fruit pollinated by bumblebees adhereto the fruit base and dry together with the style. Theseusually abscise before harvest.

Bumblebee activity on the flowerIn tomatoes, the bumblebee’s visit to the flower is visiblewithin a few hours, because it leaves a rusty-brown spoton the flower’s pistil. If no spots are visible, then thebumblebee’s activities have ceased or been reduced, andinquiries should be made with the pollination serviceprovider. Activities may cease for a number of reasons,such as:

Ageing and degeneration of the hive populationPresence of toxins on the plantsHigh temperatures in the greenhousesThe hive entrance remained closed after sprayingLack of grain pollen in flowers

39

Using bumblebees to pollinate tomatoesin greenhousesAdvantages:The bumblebee is a large insect (2 to 4 cm long) coveredby black hairs, with two lateral yellow lines and a whitestomach. This bee has three significant advantages whichprovide it with an advantage over use of other pollinators,including the honeybee:

The bumblebee shakes the flower with its buzzpollination mechanism, which is its specialty. Tomatoflowers in greenhouses or net-houses need to be shakenfor pollination, and the bumblebee is most effective forthis purpose, and is superior to any manual alternative,such as an electric bee, air pulse or application ofhormones.Bumblebees are less sensitive to extreme weather thanthe honeybee. For example, when the temperature isbelow 10ºC, with rain and clouds, the honeybee staysin the hive. However, these conditions do not interferewith the bumblebee’s activities.When the greenhouse is opened for ventilation, thebumblebee does not fly out to search for nectar andpollen. It stays in the greenhouse and does not searchfor other pastures. In general, the bumblebee’sorientation and survival in a closed greenhouse issuperior to that of the honeybee.

This comparison does not indicate that the honeybee issuitable for pollinating tomato flowers. On the contrary, itis not at all suitable for pollinating tomato flowers.Basic principles for using bumblebees in greenhouses

Bumblebee hives

Tomato inflorescence pollinated by bumblebees

A bumblebee at work

Brown spot on the pistil – sign of bumblebee activity

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40

Perfect pollination – high quality fruits

Comparison of methods for pollinatingtomato flowers: shaking compared tobumblebees (bombus terrestris), accordingto Pressman E.Tests show that bumblebees are more effective pollinatorsthan electric bees or air pulses, especially in lowtemperatures and when there are fewer pollen grains inthe flowers. This effectiveness apparently stems from thebumblebee’s frequent visits to and shaking of the flowerin these difficult conditions. Shaking by electric bee, airpulses or bumblebees to increase pollination is onlypossible when there are pollen grains in the flowers. Inwinter, when night temperatures drop below 10ºC and daytemperatures are also low, the quantity and vitality of thepollen grains in the tomato flowers decline. This is alsorelevant in summer, when temperatures are very high inthe day and also at night. There is a trend of low fertilityin the tomato flowers, which is expressed in few pollengrains in the flowers and in elongation of the style andstigma beyond the anthers, and in certain cases, theflowers do not open.

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41

Sugar water:A sugar-water solution is supplied to hives as a substitutefor nectar which is not present in tomato flowers. Thesolution constitutes an integral part of the hive. The feedingsystem provides an ongoing supply of sugar-water, whichis essential for the hive’s performance for the entire periodthat it is in use.

Placing the hive:

Place the hive in a prominent position in the greenhouse,where it is sufficiently ventilated (in winter and summer)and shaded (in the hot season). The hive should not beexposed to direct sunlight.Place the hive on a support pole, which has beenespecially planned for this purpose. Spread a line ofinsect-trapping glue on the lower third part of the poleto prevent ants fromentering the hive, as this may result in disquiet in thecolony.Ensure that the area around the hive is free of vegetation.Train the plants away from the hive. If possible, thefol iage should provide shade for the hive.

After placing the hive, allow the colony inside to calmdown, and after a few minutes, carefully open the exithole by removing the shutter that blocks it. The beeswill leave the hive and start their orientation flight, whichprovides them with the ability to find their way back tothe hive with no problem.

A hive which is set up close to sunset should not beopened until the following morning.

The original position of the hive in the greenhouse shouldnot be changed.

During the first three days, until the hive has entered intocomplete activity, an electric bee, air blower or hormonesshould be used. Manual support should only beterminated when the bumblebee has become fully active.

The bumblebee and Integrated PestManagment (IPM) in the greenhouseThe use of bumblebees in a greenhouse requires a differentpest control approach. In principle, non-chemical pest controlalternatives should be used in the greenhouse. For example,natural enemies, which have no adverse effect on bumblebees,can be used to control insects such as red spider mite andleafminer. Pesticide suppliers provide lists of pesticides thatcan be used with bumblebees, based on experience in thefield, and results of laboratory and semi-laboratory tests. Thelist is divided into groups according to the level of severity ofthe substance’s affect on the bees, and IPM is based accordingly,combining the presence of the bees in the greenhouse withthe application of pesticides.The introduction of bumblebees into tomato greenhouses hasclearly led to a significant reduction in the use of pesticides,which was an unforeseen benefit. Reduced use of pesticidesallows the development of unique marketing brands under thelabel of reduced pesticide products. Reduced pesticide usehas also resulted in significant savings in pest control expenses.

The fertigation systemThe irrigation and fertilization (fertigation) system fortomato production in greenhouses allows maximumdistribution uniformity to the entire area and proportionalinjection of fertilizer solution into the irrigation system.The irrigation system includes drip laterals for each row. The distance between drippers is determined by theplanned distance between plants, so that each plant hasits own dripper. In light soils, the drippers are closertogether, so that the entire growing strip is wetted, withoutwasting large amounts of water and fertilizers. In thesecases, there are two drippers for each plant. The seedlingsare planted next to the drippers. The dripper dischargeis 1.5 - 2 l/h, depending on the type of soil and hourlydischarge in the plot. Heavy soils have a slow infiltrationrate, therefore it is not recommended to use high volumedrippers, in order to prevent runoff as a result of excessdischarge.The fertilizer system generally includes one central pumpfor injecting the principal fertilizer and another pump forinjecting other elements such as iron, manganese,magnes ium and ca lc ium, when necessary.Large greenhouses with a number of varieties and differentplant ages, which require different water applications andfrequency, should have an irrigation system which allowscontrol and command of smaller field units. This alsosupports the operation systems, discharge capacity andcontrol system in the fertigation head and allows applicationof water and nutrients according to the requirements ofthe different varieties and planting ages.

IrrigationThe plant’s water requirements are influenced by manyfactors. The main factors are: climate, includingtemperature, relative humidity, radiation and wind; andvegetative growth, which is influenced by the age andtype of plant and the leaf shape. A combination of thesefactors or each one separately, may change the evapo-transpiration rate, changing the plant’s water requirements.

19 IRRIGATION ANDNUTRITION

A combination of a number of agrotechnical factors ingreenhouses for tomato production constitutes a guaranteefor the success of IPM. These factors include: resistantvarieties; soil covering; insect protection nets; UV-blockingplastic covers; and use of bumblebees for pollination. Allthese factors, together and separately, contribute to reduceduse of pesticides.

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Irrigation principlesAfter planting, the irrigation application rate is increasedmore than the plant’s requirement. The irrigation frequencyis one or two daily applications, depending on the seasonand soil type. This special regime creates suitableconditions and maintains wetness of the root zone, whichencourages quick establishment of the seedling in the soil.

When the plant has become established in the soil (7 - 10days after planting), irrigation is applied according to 30 -40% of the pan evaporation rate. The irrigation scheduleaccording to pan evaporation increases gradually up to65-80%, at the stage when the plant fully covers the surface(flowering and fruit set of the fourth and fifth clusters). Inlight soils, hot climates or with brackish water, the coefficientmay reach 100% or more. Irrigation with this high coefficientprevents accumulation of salts in the upper soil layers andreduces the risk of sudden lack of water which createsstress conditions.Irrigation frequency varies according to soil type. In sandysoils, irrigation is applied once or twice a day. In medium-heavy soils, the frequency will be longer, according to thewater content in the root zone after irrigation. In any case,the irrigation frequency should not be more than three tofive days, as fertilizers should be applied in short intervals.

In general, irrigation intervals should not be too short, asthis does not enable development of a deep and branchedroot system. A deep, well developed root system allowsabsorption of sufficient water and nutrients, especiallywhen there is a great load of fruit on the plants or under

extreme climatic conditions, such ashot winds, when the plant’s waterrequirements increase.Table 12 discribes the radicaldifferences of daily evaporation ratesamong regions in Israel, even thoughit’s a small country. The details in thetable are used to set the dailyevaporation coefficient.

Irrigation controlIrrigation control includes a basiccontrol mechanism to monitorirrigation and ensure that it is indeedconducted as planned. A water meteris installed at the plot head andirrigation duration and its compatibilitywith the requirements is examinedperiodically, taking into account thearea discharge and water which wasallocated for that irrigation application. Another method of irrigation controluses tensiometers which provideinformation regarding the daily waterapplication required and the timingof the next irrigation.

42

Factors influencing evaportion rate

The above figure presents the factors that influence theplant’s evapo-transpiration rate and water requirements.

Table 12. Daily evaporation rate inmonths, multi-annual averages inmm/day

Month

Station1 2 3 4 5 6 7 8 9 10 11 12

AkkoGeva CarmelRamat DavidEden StationEin HahoreshBeit DaganSde MosheErezGilatBesor StationJerichoEin YahavEilat

2.33.12.11.72.41.82.81.92.92.62.43.24.2

2.83.62.22.32.82.43.02.33.43.73.44.55.5

2.64.53.43.43.93.54.23.54.94.94.56.57.5

5.05.24.45.84.85.05.64.66.76.96.810.19.8

6.05.86.38.45.76.27.86.08.38.08.311.512.5

6.86.68.99.86.37.08.86.49.48.8

10.512.914.4

6.96.68.5

10.26.57.08.56.89.38.8

10.513.114.4

6.86.27.99.56.06.67.86.38.68.09.711.513.6

6.05.66.98.25.35.87.25.57.36.77.99.911.7

4.64.64.95.84.04.35.44.15.75.35.77.28.5

3.44.03.63.32.92.73.92.54.13.93.54.46.1

2.33.22.21.92.31.82.72.03.12.62.23.14.4

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Extractor: Extracts the soil solution and enables the growerto check the nutrient elements in the soil solution. In thisway the quantity of fertilizers used can be adjusted tomaintain optimum growth.Tensiometers: Used to control irrigation and soil moisture. They help determine the quantity and frequency of irrigation.

NutritionThe tomato plant’s nutrition requirements are influencedby the basic requirements for establishing vegetative mass,stems and foliage, as well as from the yield quantity thatis expected in a specific time. The plant’s nutritionrequirements have been examined in many studies, whichhave calculated the quantity of dry material produced bythe plant and the percentages of the different nutrientelements in the leaf, stem and fruit tissue. As a result ofthis work, conventional fertilizer formulas were formulated. Most of the studies demonstrated that there is a higherpotassium concentration in the fruit than in the leaves,while there is a higher nitrogen concentration in the leavesthan in the fruit. The phosphorus concentration is similarin both leaves and fruit. There is also reference to theplant’s requirements regarding other nutrient elements,and according to the findings, Ca, Mg and SO4 elementsare also taken into account when determining fertilizersand fertilizer formulas. The microelements Mo, B, Mn, Cuand Fe in the plant tissue are checked in the same way,and their concentration in the fertilizer compound isdetermined accordingly.

Evaporation pan

Mercury tensiometers

Tensiometers and Extractors

Electronic tensiometers

43

It is recommended to place two tensiometers stations inevery plot (variety X planting date). In medium to heavysoils, three tensiometers should be placed at each station,at a depth of 25, 50 and 75 cm. The tensiometers areinstalled at a distance of 10 cm from the dripper and theplant.The upper tensiometer is inserted at the center of the rootzone and provides information on irrigation timing. Thetensiometer at the bottom part of the root zone indicateswhether the water application wetted the entire root zone. The deeper tensiometer displays whether part of the waterapplication penetrates too deeply and is wasted, or whetherall the water remains in the root zone area.In light soils, tensiometers are installed at depths of 20,40 and 60 cm. These tensiometers operate similarly tothose that are installed in medium-heavy soils.The tensiometers should be read every day at a fixed time,preferably in the morning, and the readings should berecorded continuously. Entering the data into a graphcontributes to analysis of the irrigation process and helpsto draw conclusions for future use.New technology of electronic tensiometers are used intomato greenhouses. The data and information about thesoil tension or water content in the soil are transferred tothe farmer’s PC, who consequently can control and managethe irrigation intervals and the water amount without beingphysically in the field.

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As well as the basic chemical fertilizers, it is recommendedto add organic compost to the soil once every two years.The compost should be well prepared and applied at avolume of 40 - 50 m3/ha, when the soil is being preparedand cultivated.

Fertilization during the seasonDuring the initial growing period, in the first one or twoweeks, when the plants are taking root and becomingstabilized, it is customary to apply fertilizer with a nitrogen:phosphorus: potassium ratio (N:P2O5:K2O) of 1:1:1, whichalso contains the required level of microelements. Thisencourages development of a branched and deep rootsystem. The required daily applications are about 1,000to 1,500 g/ha of nitrogen. Another compound fertilizer isapplied when the first inflorescence appears, at a ratio of1:0.3-0.5:1.5-2, and the average daily requirements ofnitrogen are 2,500 to 3,000 g/ha. This is gradually increasedto the maximum level of 4,000 to 6,000 g/ha/day of nitrogenat the flowering stage and in fruit set in four and fiveinflorescences and throughout the harvest season. Aftercutting off the plant tops, fertilizer volume can be reducedby 50 – 60%.Proportional fertilizer is started according to 100 to 150ppm nitrogen in the flowering of the first inflorescence,and the concentration is increased up to 180 to 200 ppmof nitrogen in the stage of full coverage. The phosphorusand potassium concentrations are calculated accordingto the nitrogen concentration, at a ratio of1:0.3-0.5:1.5-2.0.A study conducted in the Besor region (B. Bar Yosef)demonstrated that in the mid-winter harvest stage, theoptimal nitrogen level for a high quality yield is 200 ppmof nitrogen in fertilizer, where the N-P-K ratio is1:0.3-0.5:1.5-2. Other studies in Israel and other countriesshowed similar results for the optimum fertilizerconcentration in the harvest stage. This ratio isrecommended in the harvest stage in order to receive ahigher quality fruit.In spring, the daily fertilizer quantities are maintained,however since the daily water applications increase as aresult of higher temperatures, the fertilizer concentrationis lowered to a level of 150 to 180 ppm of nitrogen. Theother element concentrations are also reduced, howeverthe ratio between them is maintained. In compound

fertilizers, microelements can besupplied as part of the commercialfertilizer components or can beapplied separately through theirrigation system.by the plant in two ionic forms:ammonium (NH4+) and nitrate(NO3), both of which are found incommercial fertilizers. In manystudies, it was found that a highNH4+ concentration will reduce fruitsize, increase the incidence ofblossom-end rot (BER) and, in somecases, affect plant growth. Accordingto these findings, it is recommendedthat the NH4 ammonium ratio in thetotal nitrogen (N) does not exceed25% for soil nutrition.

44

Basic fertilizationBefore planting tomatoes in greenhouses, a soil test shouldbe taken so as to check the amount of potassium andphosphorus in the soil. When the phosphorus level in theupper soil layer is 35 ppm and more (according to theOlsen method), it is not necessary to add phosphorus.When the results of the soil analysis show that thephosphorus level is lower than 35 ppm, about 100 kg/haof superphosphate should be added in order to increasethe phosphorus level by 1 ppm.The required potassium level is 12 ppm CaCl2 or∆F = 3,200, or 1 meq/L. When the results of the potassiumanalysis are lower than the required values, potassiumchloride should be applied, as recommended in Table 14.

Positions of tensiometers and extractors

Macroelements (%)

Microelements(ppm)

N

4.0-5.0

Fe

70-100

P

0.4-0.6

Mn

100-250

K

3.5-6.0

Zn

35-80

Ca

2.0-4.0

CU

5-20

Mg

0.4-0.8

B

30-80

S

0.1-0.15

Table 13. Analysis of element nutrientsin tomato plants

Table 14. Fertilizing with potassium chloride(kg/ha) according to laboratory test findings

Potassiumchloride orpotassium

sulfate(kg/ha)

Results according to testing method

Soil extract (meq/L)for light soils

CaCl2 extract (mg/l)for medium and

heavy soils

over - 15

10-15

less than 10

Over - 3,200

From -3,400 to -3,300

Less than - 3,400

Over 1.0

0.5-1.0

Less than 0.5

No need to apply

500

1,000

for all soilsCal/mol

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45

Recommendation of general nutritionfor Daniela type tomatoesBase dressing-Application without soil analysis(1000m2=0.1 ha)

Organic compost (processed) 600-800 kg/1000m2

or organic compost (well prepared) 4-5 m3 /1000 m2

+100 kg of 5:11:22 per 1000 m2

+Magnesium sulfate-50kg/1000 m2

(especially for light soils)

Seasonal nutrition accordingto growth stages1. After transplanting till flowering of first cluster

Starter fertilizer-N: P2O5:K2O =1:1:1100-150gm N per day per 1000 m2

2. First cluster until flowering of fourth/fifth clusterFertilizer-N: P2O5:K2O=1: 0.3-0.5:1.5-2200-300 gm N per day per 1000 m2

3. Fourth/fifth cluster flowering until first harvestFertilizer - N: P2O5:K2O =1: 0.3- 0.5: 2400-600 gm N per day per 1000m2

4. Harvesting period until topping the plantsFertilizer - N: P2O5:K2O =1: 0.3: 2500-600 gm N per day per 1000 m2

5. Topping the plants until the end of harvest Fertilizer - N: P2O5:K2O = 1: 0: 2

400-200 gm N per day per 1000 m2

Micro-elementsMicro-elements should be supplied continuously aftertransplanting. Use a prepared micro-element mix.Keep 40-50 ppm of Mg in the drip irrigation.Keep 100-120 ppm of Ca in the drip irrigation.

Table No.15 describes the influence of fertilizerconcentrations and water quantities on the general yieldand on the percentage of fruit that is suitable for export.The results show that yield quality and quantity increasedsignificantly when fertilizer concentrations are increasedup to 400 ppm (osmotic stress). The same result isachieved when the irrigation water application is reducedto 30% of the evaporation rate (water stress). In bothapproaches improved quality and a higher percentage ofexport-quality fruit is accompanied by smaller fruit and alower general yield level. The information in the table canbe used to decide which means and stress method (osmoticor water stress) should be applied to achieve a high qualityfruit.

Producing quality fruitQuality tomatoes can be produced if a number of irrigationand fertilization principles are adhered to:

Adequate potassium and nitrogen ratios, as describedabove, especially towards the harvest season, help tocreate a fruit with a long shelf life and a uniform redcolor. Potassium deficiency results in blotchy ripening,soft fruit and a shorter shelf life.Adequate nitrogen level contributes to a strong growth,high yield and fruit of the right color and size, withoutsunscald or yellow shoulders.Suitable humidity and water tension in the soil contributeto satisfactory fruit size, quality and shelf life. Extremechanges may damage these properties.

Nutrition control and fertilizer monitoringNutrition control is similar to irrigation control and is basedon the knowledge of the contents of the soil solutions.This control method includes an electric conductivity (EC)test of the dripper water by collecting irrigation water duringirrigation. The tests show whether the fertilizers are beingapplied as planned. The soil solution is examined afterremoving it from the soil with extractors, which are installedin the root zone area at two depths: 20 cm and 40 cm inlight soil; and 30 cm and 50 cm in medium-heavy soil.

Treatment

AII

AIII

BII

BIII

CI

CII

R

Accumulatedirrigation

m3/ha

Accumulated fertilizers (kg/ha) Panevaporation

Coef.

Nitrogenconcentrationin irrigationwater ppm

Yield per ha

Totalyield(ton)

Yieldfor export

(ton)

Exportquality

fruit(%)

Nitrogen Phosphorus Potassium

5,050

12,000

5,700

12,400

2,400

4,900

3,350

390

910

880

1,800

740

1,460

530

70

170

160

330

140

270

500

490

1,140

1,100

2,270

920

1,820

960

0.75

1.60

0.75

1.60

0.30

0.75

0.57

100

100

200

200

400

400

165

165

166

153

166

63

113

100

69

32

83

36

46

74

76

42

19

54

22

73

65

76

Table 15. Effect of different fertilization and irrigation regimes on total productionand exportable quantity

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46

Iron and/or manganese deficienciesIron and manganese deficiencies are common in thedifferent growing stages and in all seasons. Extreme ironand manganese deficiencies appear in lime-rich soils andin soils lacking aeration, where flooding and excess watercause lack of oxygen and leach ions from the root zone.The deficiencies are characterized by chlorosis that appears

Magnesium deficiencyMagnesium deficiency is characterized by yellowing of themature leaves in the lower and central part of the plant.The veins remain green. Magnesium deficiency is commonin autumn and winter, when soil temperatures dropsignificantly, especially in regions where there is a lowlevel of magnesium in the water. Magnesium deficiencyis also common when the EC values in the root zone arehigh as a result of high concentrations of potassium.

on the plant crowns. In extreme situations, it results innecrosis and drying out of the young foliage anddegeneration of the plant crowns.Iron deficiency is characterized by a general lightening ofthe entire leaf, including the veins. In the beginning, signsof deficiency appear close to the leaf base, and quicklyspread to the leaf tips. Manganese deficiency ischaracterized by changes in spots of color on the leaf,which grow and join up to form general chlorosis. Veinsremain green in cases of manganese deficiency.

Soil treatmentsIf the signs of deficiency are severe, it is recommendedto apply one full application of iron chelate (6% Fe): 5-10kg/ha with two liters of manganese chelate (13% Mn), andto continue with the same materials: 8 g iron chelate and30 cc manganese chelate for every m3 of water, untilsymptoms disappear. To prevent deficiency, it isrecommended to apply 80 - 100 cc of a commercialmicroelement compound mix to one m3 of water.

The extractors are set once a week, just after the irrigationwater for that day has stopped seeping/draining in the soil,and a few hours later, the solution that has accumulatedin them is removed. The EC of this solution is tested toensure that it is not significantly higher than the EC of thedripper water. The nitrogen level in the soil solution is alsotested by using a nitrate (NO3) kit. If both of these testsare positive (dripper and extractor solutions produce thesame results), it indicates that irrigation and fertilizationare satisfactory.

A significant difference in the EC and nitrogen levels inthe dripper water and extract solution indicates that irrigationand fertilization is unsatisfactory. If the EC and nitrogenlevels in the extract are low, application of nutrients shouldbe increased. If the EC and nitrogen levels in the extractare very high compared to the dripper water, the fertilizerconcentration in the irrigation water should be reduced.As well as the tests, which are conducted by removing thesoil solution with an extractor, the soil should be analyzedin a laboratory test two or three times every season, withthe aim of adjusting fertilization to the actual soil conditionduring the growing season.

Acidifying the irrigation waterOptimal absorption of phosphorus and microelementstakes place in an acidic environment (pH=5.5-6.5).The irrigation water and much of the soils in Israel and inother neighboring countries have a high lime concentration,and bicarbonates are formed when the lime dissolves inthe soil. The irrigation and lime in the soil create an alkalinepH of 7-8. This high pH level interferes with the absorptionof some of the nutrient elements. In order to improve theabsorption of these elements by the root system, theirrigation water can be acidified with phosphoric acid (85%),nitric acid (60%) or sulfuric acid (98%).Phosphoric or nitric acids constitute a source of macro-nutrient elements and this should be taken into accountwhen planning the fertilizer formula. Acidifying irrigationwater prevents the formation of calcium sediments in thedripper, which causes gradual clogging and lack ofdistribution uniformity. It also improves the absorption ofnutrient elements. The acids should not be combined withthe fertilizer, therefore two fertilizer pumps can be installedat the control head: one to inject the fertilizer, and the otherto inject the acid. The acid is injected into the water lineabout 20-30 cm before the fertilizer is injected.

20 MICRO-ELEMENTDEFICIENCYIN TOMATO PLANTS

Iron deficiency

Manganese deficiency

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Magnesium deficiency – yellowing between veins

Phosphorus deficiency – purple leaves

Calcium deficiency - Blossom - end rotCalcium (Ca) is considered to be one of the macroelementsthat is required by the plants in large quantities, and ispresent in high concentrations in the cell walls andmembranes. In stress conditions, the supply of calciumto the young fruit is irregular, and as a result of thisdeficiency, the tissue in the blossom end of the tomatocollapses, and the damaged tissue turns dark brown. Thisis known as blossom - end rot and is characteristic in young

fruits which are still 30-70% of their final size. Tests showthat when the EC level in the soil solution exceeds 3dS/m-1 and the calcium concentration is lower than 100ppm, the plant is more susceptible to blossom-end rot.Calcium generally moves through the xylem via the waterflow in the transpiration process. However, most of thewater which reaches the tomato fruit comes from thephloem system and therefore the quantity of calcium thatreaches the fruit is relatively small compared to the quantitythat reaches the leaves. The problem may be intensifiedwhen there are short stress periods.Since cells and membranes are created in the growingzones of the plants, they may be the first plant parts inwhich calcium deficiency is apparent. Calcium is an ionthat moves with difficulty within the plant and is nottransferred from older plant tissue to younger tissue,therefore calcium deficiency is invariably noted in the youngplant tissue and especially in growing fruits. In extremecases of deficiency, damage is caused to the young planttissue, resulting in browning of young leaf edges or yellowingof the tissue between the veins in the young leaves.For tomato fruit dry matter, calcium concentrations in fruitdamaged by blossom-end rot were less than 0.08%, whilecalcium concentrations in tissues from healthy fruits werebetween 0.12 and 0.25%. Calcium concentrations in leaveswith calcium deficiency symptoms were less than 0.2%,while concentration levels in healthy leaves were between2 and 4 %.

Principal factors that encourageappearance of blossom-end rot1. Calcium deficiency in the soil or soilless culture2. Unexpected temporary soil stress3. Salinity stress as a result of salt accumulation in the

root zone4. Competition with other elements in the soil or substrate5. Relatively low humidity and hot wind conditions6. High temperatures accompanied by relatively high

humidity7. Under-developed root system8. Sensitive varieties: elongated varieties are usually

more sensitive to blossom-end rot9. High levels of ammonium (NH4).

Means to control blossom-end rot1. Sufficient calcium (Ca) supply in the irrigation water2. Regular irrigation and prevention of water stress3. Prevention of fertilizer accumulation in the soil or

substrate. In these cases, irrigation applicationsshould be sufficient to leach excessive salts.

4. Application of potassium and magnesium, accordingto plant requirements. High concentrations of theseelements in the soil inhibit calcium absorption.

5. Maintenance of proper relative humidity (about 70%)in the greenhouse, especially in autumn and spring

6. Good establishment of the plant and development ofa wide and deep root system, which provides theplant with the ability to withstand adverse conditions.

7. Planting of varieties which are tolerant to blossom-end rot

8. Avoidance of excess NH4- in the nutritional formula.

It is recommended to increase the magnesium concentrationin the water by applying fertilizer, which also containsmagnesium or by using special fertilizers, which are injectedby another pump when applying fertilizer.The magnesium level in the irrigation water should not beless than 40 - 50 ppm from the beginning of the season.The quantity of fertilizer to be added is determined aftera chemical analysis of the water that shows the magnesiumconcentration. In some studies, it was found thatmagnesium can also be supplied by spraying the foliagewith 2.5% Magnite or 2% Magnisol, both of which aremagnesium nitrate. Spraying in hot weather may burnthe foliage.

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Calcium deficiency (BER)

Calcium deficiency (BER)

Boron deficiency

Tomato plants are considered to be tolerant to salinity andare capable of growing and producing commercial yieldswhen grown in saline soils and even when irrigated withsaline water. These facts are known in Israel and aroundthe world, and this knowledge is used to establish agro-technical methods to improve the taste and quality of thetomato. However, when salinity is uncontrolled, situationsmay be created which have a negative influence on bothsoil and plants, as a result of salt accumulation in the soil.Heavy soil is damaged by the accumulation of sodiumwhich leads to the dispersal of clay particles and the soilbecoming brackish.High soil salinity results in defective water absorption bythe plant as a result of an increase in the soil solution’sosmotic potential. This leads to a reduction in cell volume,fruit size and yield quantity. In certain situations, whenthere is a rise of harmful elements in the soil (such assodium and chlorine), they are absorbed and signs oftoxins appear in the foliage. The soil salinity index iselectric conductivity (EC), which is measured in units ofdeciSiemens per meter (dS/m). The EC expresses theconductivity level, which is from all the salts in the solution.Some salts are beneficial elements (such as potassium,phosphorus and nitrogen), which the plant requires andabsorbs, and some are harmful elements (such as chlorineand sodium), which are not absorbed by the plant but theycan increase the EC and even change soil texture.Soil samples are analyzed in a laboratory for each of theions required by the plants, in order to learn the specificcomposition of salts in the soil, and to learn which factorsinfluence the increase of the soils’ EC values. The ionsinclude: phosphorus, nitrogen, potassium, calcium,magnesium, iron, zinc, manganese and copper.The analysis is also conducted on ions that are known tobe harmful to plants, such as sodium and chlorine.Main factors that encourage accumulation of salt in thesoil:1. The concentration of salts in the water which is an

indication of its quality2. Types and quality of fertilizers3. Uncontrolled nutrition- large fertilizer applications4. Volume and frequency of water application.

Improving quality and taste by irrigationwith saline waterMuch research has been conducted in Israel and othercountries, and has demonstrated that the irrigation oftomato plants with saline water increases fruit quality asexpressed in significant changes in the fruit’s externalappearance, which becomes rounder and has a strongred color. The fruit’s taste improves as a result of a sharpincrease in the concentration of total soluble solids (TSS),especially regarding the sugar and acid concentration,

21 SOIL SALINITY

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which together determine the quality of the fruit’s taste.Irrigation of tomatoes with saline water led to a reductionin the yield level by reducing the fruit size, compared tofruit on plants grown with regular fertigation regimes. Inprinciple, irrigation with water that has an EC of 2.5 doesnot damage the tomato yield.Research and accumulated experience in growing tomatoesin saline water indicate that an EC level of 4.0-6.0 dS/min irrigation water may result in changes which improvethe quality and taste of the tomato fruit, without significantharm to the yield level. Most researches show that thedecreased yield is a result of a smaller fruit size anddiameter. Good results in yield level were achieved whensalinization (increasing salinity) continued for 60 to 75days, followed by a gradual reduction. In this way a drasticreduction in the yield level was avoided. It was also foundthat with proper salinization the yield is reduced by about25-30%, compared with the yield of plants that grow innon-salinized fertigation conditions.

Salinization principles for improved fruitquality1. Irrigation with natural saline water from local wells.2. Artificial salinization by adding salt solutions:

15 % CaCl2 + 85% NaCl30% MgCl2 + 30 % CaCl2 + 40% NaCl

3. Salinization after plants have become established andflowers appear in the first inflorescence.

4. Gradual reduction of saline concentration after 60 to70 days.

5. Irrigation with large water applications at the end ofthe salinization process to leach salt whichaccumulates in the root zone.

6. Monitoring and follow-up to prevent accumulation ofsurplus salts in the soil or growing medium, by usingextractors during the salinization period to analyzeand control the soil solution.

When irrigating with saline water, steps should be takento avoid stress caused by a water deficit in the soil, andthe water tension in the root zone should be low throughoutthe salinization period. A combination of water deficit andsaline conditions leads to a significant decline in the yieldlevel, and sudden water deficiency increases appearanceof blossom-end rot.The efficiency of irrigation with saline water increases insandy soil or soil-less culture. In these conditions, theroot zone can be easily flushed when there is excessaccumulation of salts. On the other hand, in soils with ahigh level of clay, there is a risk of salt accumulation,especially with salts containing sodium (Na). Sodium maycause damage to the soil structure and texture and is verydifficult to flush out in clay soils. Therefore, salinizationtreatments to improve tomato quality are recommendedonly when tomatoes are grown in light sandy soil or insoilless culture.

Salinization of irrigation water

Increasing EC by adding Sodium Chloride and CalciumChloride in distilled water

gr./l

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50

The following graph describes the response of fruit sizeto saline water during the season (plant age is in daysfrom planting). The key indicates the number of salinizationdays (S) and salt leaching at the end of the period(+L,-L).

Response of the fruit size to salt

Vegetable production in substrates has been used formany years. In Israel, tomato production in substrates isgrowing steadily and covers close to 70 hectares. Growing

GROWINGTOMATOES INSUBSTRATES(SOILLESS CULTURE)

in substrates in greenhouses is suitable for intensive cropsand enables production in all geographical conditions.The advantages of this method are: good control andmonitoring of nutrients and irrigation, early ripening,improved fruit quality, quick transition from one crop toanother and reduced risk of soil-borne diseases. Soillessculture can be sanitized with several different methods,which are more effective in substrates than in soil. Thesemethods include soil solarization, which is highly effective,and application of Metham Sodium substances.Growing in soilless culture requires extensive professionalknowledge in fertigation methods, as well as skills inoperating automated control and command systems.

Growing media: (Substrates):Growing media which is suitable for tomato productionhas the capacity to store a sufficient quantity of water, airand nutrient elements that are available to the plant andalso has a high drainage capacity. In suitable growingmedia, excess salts that accumulate in the media andcause damage to plants can be rapidly removed. Goodgrowing media should also be lightweight with a texturethat remains stable in the long term.

Suitable growing media:Mineral media

Volcanic gravel or rock (tuff)RockwoolPerlite

Organic mediaPeatCompostCoconut coir

Mineral and organic media mixturesTuff and compostPerlite and compostPeat or coconut coir with Styrofoam beads

Tuff media packed in polypropylene containers

In experiments and observations that were conducted ontomato production in greenhouses, it was found that thesubstrates that are most suitable for tomato production arePerlite 2, Tuff rock M 0.8 or a mixture of tuff or Perlite withorganic media. The mixed growing media have a highwater retention capacity and a relatively high buffer capacity.This provides tolerance to extreme changes in the supply

Burn folaige by high salinity in the soil

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Nutrient Film Technique (NFT)The Nutrient Film Technique is an additional method usedfor growing tomatoes under soilless conditions. NFT wasdeveloped in the 1970s in the British Isles, the principlebeing that the roots of the plants grow in a shallow nutrientsolution that is kept circulating continuously.

The basic features of NFT are based on:Growing gullies that are made out of plastic film laid ona suitable slopeA tank containing nutrient solutionA catchment tank at the lowest point of the greenhouseA pump that delivers the solution to the upper ends ofthe gulliesA monitoring and control system to maintain the nutrientsolution of EC and pH

The NTF system is susceptible to damage if there is asudden interruption in the flow of the nutrient solution tothe plants, especially on sunny days. Therefore, it isessential to make adequate provisions for electrical and/ormechanical failure by ensuring safety devices, keeping aspare pump, a stand-by generator and an alarm system.

Growing containers: Size and growingmediaTypes of containers1. Styrofoam containers, with a volume of 70 liters and

internal dimensions of 115 x 40 x 15 cm. About4,000 containers are used per hectare.

2. Black PE buckets or bags, with a volume of 10 litersfor one plant. About 22,000 - 24,000 buckets orbags are used per hectare.

3. Black PE bags, with a volume of 20 liters, whichare up to 25 cm high, and are suitable for growingtwo plants per bag. About 11,000 - 12,000 bagsare used per hectare.

4. Polypropylene and polycarbonate growing troughs, of different sizes.

Dimensions of polypropylene and polycarbonate troughsHeight: 17cmBase width: 40 -50cmLength: According to the slope in the greenhouse and thedrainage holes of the trough. If the slope is sharp and thetrough has no holes, it is recommended to use shorttroughs of 10 to 15 m. If the troughs have drainage holesat the sides, troughs of up to 30 m or more can be used.

Types of growing media according tocontainer type1. In large containers (Styrofoam, polypropylene, and

polycarbonate troughs): unsifted tuff 0-8 M, Perlite, oran organic mixture. Media volume: 300 – 500 m3/ha.

The compost that is used in the mixture is composedof mule manure and grape dregs at a ratio of 1:1re: to volume.

Growing tomatoes in rockwool substrate

Table 16. Physical propertiesof various substrates

* Natural tuff moistness

Property

Air capacityat 10 cmtension

Hermonittuff

0.8 MAgrimanCocount

Salitrockwool

Perlite 2 foragricultural

use

OptimalValues

Calculatedporosity (%)

MeasuredPorosity (%)

A WP-Availablewatercapacity (%)(10-50 cm)

WBC-WaterBufferingcapacity (%)50-100 cm)LRAW-Lessreadilyavailablewater (%)(100 cm andabove)

Bulkdensity(kg/m3)*

20-6

55-65

43-46

12-15

2.5-3.5

17-22

1,200-1,300

30-33

85-93

20-24

2-2.5

30-34

80-90

23

80-85

55

0.2

6

90-110

24

85-90

83

21

33

60-80

5

20-30

20-30

4-10

_85+

of water and nutrient elements to the plants which mayoccur during the growing process. On the other hand, theuse of mineral growing media without any added organicsubstance, such as rockwool, Perlite or tuff, requiresmeticulous control of the fertigation system in order toprevent extreme changes in the supply of water and nutrientelements.Research shows that the addition of organicsubstances to the substrate freguently reduces theincidence of soil-born diseases.

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2. In small containers (bags or buckets): A mixture ofsifted Tuff B 0-8 or Perlite (70%) with 30% compost.The growing media volume is about 250 – 300m3/ha.

3. Rockwool packed with plastic cover, no need forcontainers.

CommentsVarieties that are sensitive to blossom-end rot shouldbe grown in large containers.It is recommended to paint the exterior of the blackbuckets or bags white to prevent the growing mediumand root zone from over heating.

Drainage of containersDrainage of excess water from the growing containers isnecessary to ensure healthy plants. Water that accumulatesin containers with no drainage reduces the oxygen levelin the growing medium. This damages the root system’sability to absorb nutrient elements, especially microelementsand creates chemical compounds that are harmful to theplants. A good example can occur when nitrates (NO3)encounter lack of aeration and are converted to nitrites(NO2) which is toxic to the plants. In addition, when thereis insufficient aeration in the growing medium, the risks ofdeveloping root diseases are higher. In order to drain thecontainers and remove the surplus water, steps should betaken to ensure that the water drains off easily from theoutlets in these containers.Styrofoam containers should be perforated before planting,with 3-4 drainage holes on each side, totaling 6 – 8 drainageoutlets for each unit.There are two methods for draining polypropylenecontainers:1. Drainage along the length of the growing container:

A drain, which is attached to a collection pipeperpendicular to the crop rows, is installed at the endof the unit (the crop unit is 10-15m in length).

2. Drainage on the sides of the containers: There is anoutlet every 30-40cm. Options for this drainagemethod include:

Side drainage to two gravel ditches, which are oneither side of the containerSide drainage to a central gravel ditchunder the containers

In small containers, buckets or bags, 4 - 5 holes shouldbe punched in the lower part of the container (not in thebase). It is recommended to punch holes around the entirecontainer diameter. The diameter of the holes should be8-10 mm.Advantages: Polypropylene containers are heat resistantand are suitable for steam sterilization, unlike Styrofoamcontainers which are not suitable for this, as they aredamaged at temperatures around 80ºC.

Covering the containersThe containers are separated from the soil by a black0.15-0.2 mm PE sheet which is spread over the soil.Before spreading out the PE sheet, the area is leveledand a suitable slope is created (0.8 – 1.0 percent), whichallows excess water to flow out of the greenhouse. Waterthat stagnates in the greenhouse constitutes a source ofdisease. The Styrofoam containers are wrapped withblack-white PE film (white on the outside), which is 1.3 mwide. This creates a drainage canal to carry the drainagewater along the row. The PE sheet is spread out beforethe containers are placed on the ground. Holes arepunched in the upper side of the PE sheet as preparationfor planting the seedlings. PE sheets are used as acovering or as a means to carry drainage water along therow. Polypropylene sheets, which are thinner, can alsobe used for this purpose. This material is usually durablefor many years.

Containers filled with agricultural Perlite

Preparation for soilless culture:polypropylene containers

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Preparation for soilless culture

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Rinsing the growing media before planting

New organic growing media mix: After the containers arefilled and placed in the growing area, they are irrigated toleach salts from the growing media. After rinsing, the EClevel in the drainage water should be lower than 1.5 dS/m.Old growing media: Experience shows that there is asignificant accumulation of salts at the end of the growingseason. This may cause serious damage to the new cropand therefore the growing media should be rinsed in thesame way as new growing media.

Enriching new tuff with phosphorusSince the new tuff absorbs most of the phosphorus in theirrigation water, restricting phosphorus absorption by theplant, it is recommended to enrich the tuff with this elementbefore planting. The tuff is enriched with 100-190 cc ofphosphoric acid per 1 m3 of water (according to thebicarbonate content in the water). During the acidifyingprocess, acids cause a titration of bicarbonate in the water. It is usually possible to titrate 1 ppm of bicarbonate byadding 1 cc of phosphoric acid to 1 m3 of water. About 50ppm of bicarbonate should be maintained in the waterduring the acidification process to prevent a drastic declinein the pH. For example, 50 cc of phosphoric acid for each1 m3 of water is added to water which contains 100 ppmof bicarbonate while 100 cc of phosphoric acid for each1 m3 of water is added to water which contains 150 ppmof bicarbonate. The phosphoric acid is applied with aheavy irrigation session, while ensuring proper drainageand wetting of the growing media. When the phosphoricacid is injected into the irrigation water, the pH level of thedripper water is tested to ensure that it does not drop below5.5.

Irrigation equipmentThe irrigation equipment is chosen according to the typeof container. One dripper with 2-4 l/h discharge is usedfor each plant in small containers (bags or buckets). Thisallows effective salt leaching. In containers that arearranged in a row, such as Styrofoam or polypropylenecontainers, two drip laterals with 1-2 l/h drippers are used,with 15-20 cm between drippers. Low-volume drippersare recommended.

Irrigation regimeThe irrigation regime during the growing season is influencedby a number of factors.Main factors:1. The plant’s daily water consumption is influenced by

the different growing stages, the season, region andclimatic conditions.

2. Volume of irrigation is influenced by daily consumptionand drainage rate. An adequate quantity is requiredto prevent accumulation of salts - especially sodiumand chlorides - in the growing media.

Table 17. Recommended drainage rateaccording to Chloride concentration in theirrigation water

Chloride concentration(mg/l)

Below 150

150-250

250-300

Over 300

Drainage rate (%)

20-25

30-40

40-50

50-60

3. Irrigation frequency is influenced by the plant’srequirements and the percentage of water that is availableto the plant. This depends on the type, volume and ageof the growing media. Growing media that is composedof an organic matter mix usually has a high water retentioncapacity and accordingly the water volume that is availablefor the plant is relatively high. On the other hand, the watervolume that is available for the plant is lower in growingmedia with a low water retention capacity.The age of the growing media also influences the waterretention capacity. For example, tuff that has been usedseveral times has a greater volume of small aggregatesin the growing media. This leads to a higher water retentioncapacity, resulting in an increase in the available watercapacity. The growing media volume has a decisiveinfluence on determining irrigation frequency. In a smallvolume of growing media, irrigation frequency is high, andin a large volume of growing media, irrigation frequencyis low. This approach is relevant to all types of growingmedia.

The irrigation regime and irrigation management for cropsgrown in soilless culture are determined on the basis ofinformation on the plant’s requirements, irrigation frequencyand size of irrigation application.

Collection of drainage and irrigation water

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NutritionCompound (NPK) fertilizers can be used, or fertilizer solutioncan be prepared by mixing a number of different types offertilizers. One or two tanks are used, with a size that iscompatible with the size of the area. The use of more thanone tank enables application of fertilizers that cannot bemixed due to sedimentation or disintegration of some ofthe nutrient elements. In addition, the use of more thanone tank allows nutrient elements, such as calcium,manganese and sulfur, to be added to the irrigation wateraccording to the crop requirements, and enables controlof the pH level in the growing media through use of acidsor by changing the ammonia-nitrate ratio in the fertilizersolution. The use of more than one tank requires a numberof pumps (one pump per tank) which operate simultaneouslyand inject fertilizer solution into the irrigation system. Infertilization which is applied with one tank and one pump,compound fertilizers or fertilizer mixtures – such asammonium sulfate, phosphoric acid and potassium – canbe used. In soilless culture it is important to acidify theirrigation water in order to prevent sedimentation of saltsand clogging of drippers, and in order to stabilize the pHlevel in the growing media.

Table 18. Fertilizer compositionrecommended in two tanks (one pumpper tank)

Concentration of required microelements in the irrigationwater is expressed in ppm Fe: 1.2-1.4; Mn: 0.6-0.7;Zn: 0.3-0.4; Cu: 0.1-0.2; Mo: 0.05-0.1; B: 0.25-0.3

Comments:

When mixing fertilizers independently, 120-150 ccmicroelement mix and 5 g iron chelate (6%) are addedfor every m3 of water. When fertilizing with compoundfertilizers (NPK), it is recommended to enrich them withmicroelement solution (6%) and magnesium (0.5%).It is recommended to prepare a container to collectdripper water by connecting a dripper and tube to theirrigation pipe. The dripper water is collected in a closedcontainer for chemical analysis and the results arecompared with those of the drainage water.Ammonium-nitrate ratio: The quantity of ammoniumconstitutes about 10-20 % of the total nitrogen in thefertilizer solution (according to growing season).The calcium and magnesium concentration in the fertilizersolution is calculated after determining the level of theseelements in the tap water.

Irrigation and fertilization controlGrowing tomatoes in soilless culture requires strict irrigationand fertilization control throughout the growing stages:It is recommended to test pH, EC, nitrate and chlorinefrequently, using field kits. Once a month, pH, EC, NO3,P, K, Ca, Mg, CI and B should be tested in a laboratory.

pH: The pH level in the dripper water should be6.0-6.5. Acid can be used to bring the pH level downto these values. The bicarbonate content in the wateris determined and then acid quantities are calculated.EC: The electric conductivity of the dripper waterdepends on the EC of the tap water plus the fertilizersolution. The difference between the EC of the drainagewater and the EC of the dripper water should not exceed0.4-0.5 dS/m (according to water quality). If thedrainage water EC exceeds these values, the chloridelevel in the drainage water from the growing mediashould be tested. If the chloride level exceeds thechloride level in the tap water by 50-100 mg/l (but thenitrate level is satisfactory), it should be rinsed withwater, without reducing the fertilizer concentration.If the chloride level is satisfactory, but the nitrate levelin the drainage water is much higher than in the dripperwater, it should be flushed with water containing half ofthe fertilizer concentration. The chlorine test is alsoimportant to determine the size of the irrigationapplication.Nitrate (NO3) test: The nitrate level in the drainagewater should be about 500-850 ppm. The nitrateconcentration in the dripper water varies according tothe crop cycle and growing season. If the Litmus papertest shows concentration exceeds 500 ppm (red dark),the solution should be diluted with distilled water at aratio of 1:1, and the result should be multiplied by two.It is recommended to measure the daily quantity ofdrainage water to determine the fertigation regime. Ifdrainage is higher than recommended (30%), the waterapplication is reduced, and if drainage is lower than

Table 19. Concentration of elements inirrigation water (dripper)

Tank A

Calcium nitrate(powder or liquid)

Tank B

Magnesium nitrate(if required)

Potassium nitrate(half the quantity)

Phosphoric acid

Potassium nitrate(half the quantity)

Nitric acid

Microelement mix(with Boron, if required)

Sulfuric acid (if required)

Chelate iron Ammonium sulfate

Liquid ammonium(if required)

Stage of plant growth

Planting and establishment

g/m3 (ppm)

100-120N

40-50P

150-180K

100-120Ca

40-50Mg

Flowering in firstinflorescence until floweringand fruit set in 4-5inflorescences

150-180 40-50 250-350 100-120 40-50

Flowering and fruit setin 4-5 inflorescences and soon and picking period

180-200 40-50 300-400 100-120 50-60

Hot season(spring-summer)

150-180 35-40 250-300 100-120 40-50

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30%, the number of irrigation sessions and total dailyapplication is increased.The dripper and drainage water tests are conductedwith reliable field kits, which are calibrated and adjustedto the conventional values in qualified laboratories.

Ensuring reserve waterReserve water tanks are required when growing crops insoilless culture. These tanks should have a volume ofabout 100-150 m3 per hectare, which is sufficient irrigationwater for one or two days. This will ensure a continuouswater supply if there is a disruption in the regular watersupply or a malfunction in the central irrigation system.

Field kits for chemical testsA number of tests, which provide the grower with basicdata, can be easily conducted in field conditions. Thesetests can be used to compare solutions that are collectedfrom drainage or pumps with dripper water. The kits thatare chosen should be reliable, easy to use and inexpensive.

The following kits can be used in field conditions:1. EC meter (digital): Requires daily calibration; the

electrode should be rinsed after use with a solutionthat has a known EC.

2. Kit for testing pH:Electric pH meter (digital): Requires dailycalibration; is sensitive due to accumulation ofsalts on the electrode.Drops for testing pH: Usually produce reliableresults.Sticks for testing pH: Usually produce reliableresults.

Influence of pH on availability of essential nutrients in soil

Curling of top leaves – surplus fertilizer

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3. Nitrate and nitrite kit: The litmus paper has two bands.The upper checks nitrite (NO2) and the lower checksnitrate (N03). When there is no nitrite, the striperemains white, however, when there is nitrite, the stripeturns pink or red. Nitrite is toxic and damages the rootsystem, and indicates a lack of oxygen in the growingmedia.

The nitrate kit tests up to 500 ppm. If the color is toodark, the solutions should be diluted with distilled waterwith a ratio of 1:1, and the result should be doubled.Comment: The nitrate kit tests nitrate only and doesnot provide data for all the Nitrogen in the solution.

4. Chloride kit: This is based on drops and titration.It supplies data on the Chloride concentration in thesolution that is being tested. Using the informationthat is received, it is possible to analyze irrigationprocedures especially the size of the irrigationapplication.

In greenhouse tomato production, where crops are grownin soilless culture, a significant amount of drainage waterruns off from the greenhouse to the environment. Thisconstitutes an environmental hazard for various reasons,some of which are listed below:

Environmental pollution and constant wet soil aroundthe greenhouse.Growth of unwanted weeds in the different seasons,which serve as a host for diseases and pests.Penetration of nitrates and other toxins into the soil thatcan pollute the ground water.

A high percentage of drainage water runs off from thegrowing media after each irrigation application. Thisconstitutes a waste of water which is valuable, as it containsa high concentration of fertilizers. The drainage percentageis influenced by the irrigation frequency and initial waterquality (chloride concentration in water). This watercontains a high level of elements, which is similar to theconcentration of microelements in the dripper water. Thehigh level of elements in the drainage water increases theeconomic value of the water, and thus by collecting theexcess water in tanks, it can be reused for irrigation.The most efficient system for recycling drainage water isa closed recycling system. This system collects the drainagewater and returns it to the crop after a sterilizing processwhich eliminates pathogens such as fungi, bacteria andviruses.When planning a closed recycling system, the following

Field kits for chemical tests

23 RECYCLINGDRAINAGEWATER

Diagram of a recycling system

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Containers for collecting drainagewater and reservoirs

Sterilizing drainage waterMethods for sterilizing drainage water:

UV radiation: This system destroys fungi, bacteriaand some viruses. The method requires meticulousfiltration of the drainage water to increase its claritybefore sterilizing with the UV tube.Filtration by a biological filter: This method is efficientand is recommended for selective sterilization ofpathogens, especially fungi.Chlorination: Active chlorine is added to the drainagewater. The chlorine concentration is suitable fordestroying the pathogens and does not damage theplants. The method is already being applied incommercial farms.Thermal sterilization: In this method, the drainagewater is heated to between 65ºC and 85ºC for threeminutes. This method is efficient for destruction of mostpathogens, fungi, bacteria and viruses.

Ventilation in greenhousesVentilation in greenhouses for tomato production hasmany purposes, the main ones being:1. To remove humidity2. To remove excess heat3. For CO2 enrichment4. To remove noxious gases

Ventilation to remove humidityPlants grown in closed structures emit great amounts ofwater vapor into the atmosphere, and consequently thehumidity rises to high levels. When the externaltemperature of the greenhouse is lower than the internaltemperature (usually at night), the plants cool rapidly andcondensation forms on the foliage. Moreover, water vaporaccumulates on the internal surface of the structure’scovering. If the plastic film does not have anti-drip additives,the accumulated moisture drips back onto the plants.High relative humidity also creates conditions fordevelopment of various fungal and bacterial leaf and fruitdiseases. In high humidity, the propagation and ripeningprocesses are disrupted, stamens do not open, pollen isnot released, and the quality of the fruit is damaged. Inwinter, it is often necessary to ventilate the greenhouseto remove excess humidity, even though this causes lowtemperature.

Ventilation instructions1. In non-heated greenhouses, it is recommended to

have narrow openings along opposite sides of thegreenhouse at night. On nights when frost is expected,the sides should be closed down if thermal plastic film(IR) is used, however the openings should not beclosed if regular film is used.

2. In heated greenhouses that do not have ventilationsystems, it is recommended to remove humid air byopening two opposite sides of the greenhouse duringthe evening hours and in the early morning, whileincreasing the heating.

3. In heated greenhouses, with ventilation system fans,the fans should be operated for 1-2 minutes every20-30 minutes (20 fans per hectare). The operationand regulation of ventilation depends on the amountof water vapor emitted by the plants and the humiditylevel inside the greenhouse.

4. If there is a climate-control system, the humidity controlshould be based on the combination of air exchangeand heating manipulation.

Ventilation to remove excess heatOn clear sunny days, temperatures inside a closedgreenhouse may become too high and could damage theplants, encourage development of diseases and pestinfestation, and harm the proper development of the plants.Exchanging the air inside the greenhouse with outside

24 GREENHOUSEVENTILATION

basic needs should be taken into account:Preparation of infrastructure to collect the drainagewater and rainfall, and if necessary improve the tapwater. The infrastructure should include a pipe system,reservoirs and pumps.Dilution of the drainage water with tap water or rainwater to reduce brackishness in the drainage water.Filtration and disinfection of the drainage water witha system that takes into account the sensitivity of theplants to pathogens that are transferred in the drainagewater.Control system to monitor fertigation and to determinethe EC and pH level and the concentration of nutrientsrequired by the plants.In a closed recycling system, chemical testing shouldbe constantly performed, to ascertain the quantity ofelements and for pathological control, to ensure theefficiency of the drainage water’s sterilization system.

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air helps regulate the temperatures, especially when theexternal temperature is lower than the internal temperature.

Excess heat can be removed in thefollowing ways:1. In winter, it is sufficient to operate twenty 48” - 50”

extractor fans for each hectare to remove excess heatand humidity. The fans are operated by a regulatorset to the required temperature of 26º-28ºC. Thecurtain on the side of the greenhouse where the fansare installed remains closed while the curtain on theopposite side is opened to a height of 30 cm, allowingfresh air to enter the greenhouse.

2. In greenhouses without fans, the curtains should beopened in accordance with outside wind velocity anddirection. The opening on the side facing the windshould be narrow, while the opposite side should beopened to its maximum. In principle, curtains shouldbe left open as much as possible.

3. During spring and summer, when the outside air ishot, it is difficult to maintain the required temperaturesinside the greenhouse. Every means available to thegrower, such as opening side curtains and roofwindows, and operating extraction and circulation fans,should be used. When the temperature rises to highvalues, one of the shading methods described in theShading chapter can be used to reduce the heat load.

Ventilation for passive CO2 enrichmentAll ventilation methods result in passive CO2 enrichmentin the greenhouses. In closed structures, the CO2concentration in the greenhouse air and plant environment

Greenhouses with roof vents, passive ventilation

As stated in the chapter dealing with climate, tomato plantsrequire precise temperatures. When the temperaturedrops below a certain minimum, tomato plants are damagedconsiderably, resulting in inferior yields and quality.Experiments and observations carried out at experimentalstations and tomato farms show that optimum yields anddesired quality are obtained in Israel when the minimumtemperature is increased to 12º-14ºC. In countries withlow day temperatures, more night heating is usuallyrequired.Main advantages of heating tomato greenhouses:1. Regulated growth and development2. Good plant fertility and fruit set3. Efficient absorption of nutrients by plants4. Improved quality of fruit color and shape5. Continuous and reliable product supply to the market

and for export6. Reduced use of pesticides

25 GREENHOUSEHEATING

Frost - damage to foliage

Frost - damage to fruit and foliage

is drastically reduced to 180-200 ppm, compared to theconcentration outside which is 320-340 ppm.Air replacement changes the CO2 concentration in thegreenhouse and increases the concentration to the samelevel as on the outside. These ventilation methods allowthe plants to function normally, without any damage to thephotosynthesis process or to the yield and fruit quality.

Greenhouse with fans, active ventilation

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Heat transmission via hot water pipesCirculation of hot air via plastic sleeves

60

rows, to provide better circulation of hot air throughoutthe greenhouse. The heater should be placed on araised concrete platform to prevent corrosion andother damage to its casing. The wind direction andvelocity, as well as the location of the extractor fansand wind shear, should be taken into account whenpositioning the heater. The heater booth should havea door to the outside, allowing easy access withoutthe need to pass through the greenhouse. A light andelectricity socket should be installed in the booth foruse at night.

3. Control regulators should be installed in a waterproofbox. Regulator sensors are placed in ventilatedcontainers that protect the measuring equipment fromdripping water and direct sunlight. The sensors shouldbe installed where they can read the temperaturerequired in the greenhouse.

4. A system of plastic sleeves for heating with hot air isplaced along the floor to distribute hot air. The sleeveshave holes all along the length. The holes are notspaced uniformly - they are closer together at the endfarthest from the heater and become further apartcloser to heater. The diameter of the air circulationsleeves is usually 23 - 25 cm.

5. An external fuel tank should be positioned close tothe greenhouse, in accordance with safety regulationsand with easy access for refilling. Heaters requireregular maintenance and periodic services to ensurethat they are in efficient working condition. When thegreenhouse is completely sealed and a thermal screenis used efficiently, the required heat output will be20 -30% lower.

Heating methodsThere are three main methods for heating greenhouses:1. Heating with hot air: Hot air circulates through

perforated plastic sleeves that are placed in the pathsbetween the plant rows or between row pairs.

2. Heating with hot water: Heat transmitted by hot waterflows through a system of metal pipes that arepositioned along the plant beds or in the paths betweenthe rows. These are also used for moving and operatingequipment and as an accessory for greenhousetreatments.

3. Combination of the two systems: hot water system anddistribution of heat through heat exchange using sleeves.

Positioning and operating heaters in tomato greenhouses:1. Even when heating the greenhouse, heat is lost to

the ambient. To reduce heat loss and minimize heatingcosts, ensure that the curtains, windows and entrancesare well sealed.

2. A hot air heater is designed to draw in air, heat it anddischarge the heated air back into the greenhouseatmosphere. The heater’s kcal per hour output isselected according to the temperature (∆T) differencebetween the prevalent minimum temperature and therequired temperature. If the outside temperature oftendrops to 4ºC, the heater required to raise thetemperature to 12ºC should be able to provide the8ºC difference per 0.1 hectare. About 10,000 kcal/hare required to raise the temperature by 1ºC in a 0.1hectare greenhouse. Therefore an 180,000 kcal/hheater would be suitable for heating a 0.2 hectaretomato greenhouse. An air heater that heats andcirculates air throughout the greenhouse should beinstalled inside the greenhouse or in a special boothadjoining it. The booth, which is closed from theoutside and open from the inside, should be attachedto the side of the greenhouse.The heater should be centered on the side of thegreenhouse, opposite the pathway at the end of the

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26 CO2ENRICHMENTFOR TOMATOES

The photosynthetic process:CO2 + H2O + light } C6Hl2O6 + O2CO2 is considered to be one of the most importantcompounds in plant life. During photosynthesis, plantsutilize the CO2 from the atmosphere in order to producesugars. The concentration of CO2 in fresh air is about 330ppm. When the greenhouse is closed, the plants use theCO2 in the greenhouse for photosynthesis. This results ina drop of the CO2 concentration the greenhouse air. Inaddition to ventilation for the removal of heat and humidity,CO2 enrichment ventilation is introduced to restore thegreenhouse CO2 concentration to fresh air levels. Researchshows that the introduction of CO2 into the greenhouseatmosphere greatly increases the vegetative growth ofmany plants, including tomatoes.Results of studies in Israel indicate a positive response toCO2 enrichment in greenhouse tomatoes grown duringthe winter and spring months, with yield increases of8-12%. Financially, this increase does not justify the requiredinvestment and running costs. The relatively low yieldincrease stems from the fact that in Israel, wheretemperatures rise to extreme levels even in winter andrequire ventilation and opening of curtains, CO2 enrichment,which is performed in closed greenhouses to prevent lossof gas, is applied for relatively short periods. On the otherhand, in countries further north, such as Holland, Franceand Belgium, where the climatic conditions enable morehours of enrichment during the day, CO2 enrichment intomato greenhouses is found to have significant advantagesand financial justification. Therefore many greenhousesin these countries incorporate CO2 enrichment systemsto improve yield and quality.The recommended enrichment level is 700-1,000 ppm,and the conventional enrichment level is 900-1,000 ppm.

Ethylene (C2H4) is a colorless and odorless gas whichacts as a hormone even in low concentrations. It servesas a growth regulator and constitutes a positive factor byencouraging seed germination, root development and fruitripening.In high concentrations, ethylene is harmful to plants. Thetomato plant is considered to be very sensitive to ethylene,and it serves as an indicator for the presence of the gas. Tomato plants are damaged by ethylene at concentrationsof 0.01-0.05 ppm. The symptoms and damage areexpressed as deformation of leaves and flowers.The leaves curl downwards and become yellow, growthis stunted and flowers abscise, especially those whichhave not started to develop as fruit. Since it is not possibleto discover the ethylene in the greenhouse air in advance,increased ethylene concentration is indicated by damageto plants.There are different reasons for increased ethylene levelsand these include the release of ethylene by ripening orrotting fruit. However, the most common reason is a faultyheating system that produces ethylene as a by-productof poor combustion.The most common cases of ethylene damage wereobserved when there was uncontrolled use of liquid CO2tanks used for CO2 enrichment.The heating system in the greenhouse should be checkedregularly and there should be proper ventilation to removetoxic gases before they accumulate to harmful levels.

27 ETHYLENEDAMAGE

Photosynthesis

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Disappearance of growing crownWhen indeterminate plants stop growing for unknownreasons, an inflorescence or leaf appears at the crown,similar to that at the end of growth in determinate varieties.This is common in fields where the plants have densevegetation, a thick stem and large leaves, as a result ofuncontrolled irrigation and fertilization. It appears in differentseasons and in most commercial varieties.In general, disappearance of crown occurs following5-6 normal inflorescences in the plant, and it appears inonly a small percentage of the entire crop. In certain cases,termination is complete, while in other cases a newsecondary branch grows to replace the original crown.When disappearance of growing crown is encounteredand the determinate plant stops growing, a secondarystem should be developed to replace the main stem, or asecondary stem should be allowed to grow on an adjacentplant, to compensate for the plant which has stoppedgrowing.

62

Leaf rollPlants with leaf roll have a lower photosynthetic andtranspiration rate, which may result in a significant reductionin yield. Leaf roll is the plant’s response to extreme stressconditions, such as continuous low or high temperature.In harsh conditions, the leaves curl inwards and take ona shape of deep, half-closed teaspoons. The curled leavesbecome brittle and fragile. When leaf roll is more severe,the fruit is exposed to the extreme climatic conditions andquality is damaged by susceptibility to fruit cracking, differentlevels of sunburn and even damage to their firmness. Thecurled leaves maintain full turgidity and do not wither.Different varieties have different levels of sensitivity to leafroll. These differences are also expressed in less extremeconditions. Leaf roll becomes more severe when the plantrows are east-west. There is a greater incidence of thisdisorder on the southern side of the rows. Planting innorth-south rows significantly decreases incidence of leafroll.

Curled leaves, low temperature

Stopped growthwithout renewalof secondary

branches

Development ofa secondary

branch followingend of growth

Curled leaves, direct radiation

28 GROWTH ANDFRUITDISORDERS

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Cracks in tomatoesThere are three types of cracks in tomato fruit:1. Radial cracks: cracks that develop from the calyx

towards the tip of the fruit2. Concentric cracks: cracks that partially or completely

encircle the calyx3. Micro cracks: minute cracks that develop around the

shoulders of the fruit and are usually not uniform inappearance or quantity

Micro cracks

Concentric and Radial cracks

Concentric cracks

The main causes of fruit cracking are:1. Fluctuation in soil moisture, which causes concentric

cracking.2. Wet vegetation, usually by rain in open fields.3. Extreme differences between day and night

temperatures, which create conditions for the expansionand contraction of the cells in the fruit.

4. High atmospheric humidity that limits evaporationthrough the foliage and creates water stress, causingcracks.

5. Tomatoes that are exposed to direct sunrays and lackfoliage cover. Generally the higher clusters, which areclose to the support wires, are especially affected bythe extreme temperature differences.

6. High sugar concentrations and general soluble solidsin fruits generate lower osmotic potential in the fruitthan in other parts of the plant, encouraging flow ofwater into the fruit and thus forming cracks. This isvery common in cherry tomatoes.

7. Old plants and plants with sparse vegetation, small,damaged and defective leaves, have limitedevaporation through the foliage and this can result incracking due to excess water reaching the fruit.

8. Strong removal of leaves results in reduced evaporationand lack of fruit cover, which increases cracking dueto root pressure.

9. Low levels of nutrients, especially of potassium (K)and calcium (Ca), which are essential for building andstrengthening cell walls.

10. Early morning condensation on fruit, when the fruittemperature is lower than the air temperature,par t icu lar ly encourages micro crack ing.

Cracks on all the fruitof the cluster

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Means to reduce cracking on tomato fruit1. Extreme soil dryness followed by a large volume of

irrigation causes fruit cracking. Therefore, it is importantto follow a regular irrigation routine and maintain astable soil moisture level.

2. In winter when temperatures are low, days are shortand plants are not in the best condition, it is necessaryto irrigate with very small amounts of water to preventaccumulation of excess moisture that might not beabsorbed by the plants due to climatic conditions andlimited growth. On the other hand, the excess moisturecould be absorbed by the roots, which creates pressureon the fruit and causes cracks.

3. Leaves should not be removed from plants, especiallyin winter, to increase the vegetative evaporation surfaceand thereby reduce water stress on fruit.

4. Suitable greenhouse ventilation is required to removeexcess humidity from around the foliage and fruit.Damp fruit absorbs the condensation, which results infruit cracking.

5. New and continuous growth and healthy foliage shouldbe encouraged, to promote a continuous transpirationstream and evaporation of water absorbed by the roots.

6. Plant protection, to maintain healthy plants. Damagecaused by mildew, leaf mold and other diseasessignificantly reduces the foliage evaporation surfacesand causes over-exposure of fruit, which encouragescracks.

7. Fertilization with Calcium (Ca): Calcium should beapplied, and its availability to and absorption by plantsshould be ensured, without creating competition withvarious nutrients in the soil or bedding material.The recommended concentration is 100-120 ppm.

8. Fertilization with magnesium (Mg): In winter whenthe temperatures are low, magnesium is more difficultto absorb, causing deficiencies in foliage, especiallyyellowing between the veins. This reduces evaporationthrough the leaves, causing water stress on the fruitand increasing cracking. Therefore, during this seasonthe Mg concentration should be increased to 50-60ppm (including the initial concentration in water).

9. Because a large amount of fruit cracks after beingpicked, cherry tomatoes should be left in crates in thepacking shed for at least one day to ensure that thefruit that cracks during this period can then beeliminated during the grading and packing process.

Puffiness in tomato fruitThe formation of a gap between the fruit wall and the carpelseed pulp is known as fruit puffiness or hollowness. Hollowtomato fruit lack firmness and have a short shelf-life. Theyrot quickly and their shape is not characteristic of thevariety.Factors encouraging puff iness in tomato fruit1. Excessive use of Nitrogen when applying fertilizers:

prevalent during all seasons.2. Excessive use of fruit-set hormones: prevalent in fruit

treated with hormones.3. Lack of sunlight: widespread in spring, and especially

in winter fruit set (short, cloudy and cold days).

4. Genetic susceptibility: certain varieties are especiallysusceptible to puffiness, while others are relativelytolerant.

Hollowness, Excess of hormones

Triangular hollow fruit – internal view

Triangular hollow fruit – external view

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Control of puffiness1. Controlled fertigation and creation of slight stress to

prevent unbalanced growth.2. Careful use of frui t-set growth hormones.3. Increase the sunlight in the greenhouse and between

plants by:a. Cleaning roofs especially in autumn and winter

and whenever they are covered with dust.b. Arranging the support system to allow sunrays to

penetrate between the double rows, by maintaininga distance of 60-70 cm between the horizontalsupport wires.

4. Prevention of overcrowding of plants in the rows.5. Planting of varieties that are less susceptible to puffiness.

Blotchy ripeningBlotchy ripening in tomatoes appears as lack of color incertain areas of the fruit. The blotches are not uniform inshape or size and often run into one another, spreadingover a large area of the fruit surface.These blotchy areas do not turn red, but tend to remaingreen with brown spots. The fruit turns brown on the inside,especially around the walls, which is known as brown wall.The un-ripened areas usually remain firmer than the redareas. This problem is prevalent in the winter and spring,and usually affects the first, second and third fruit clusters.

Research and experiments indicate that climatic conditionsgreatly influence development of blotchy fruit. There is ahigh probability that blotchy ripening will develop on fruiton the first clusters under conditions of low temperature,lack of sunlight and high humidity.In autumn plantings and harsh winter conditions, the plantsgrow and develop slowly and a dense vegetative masswith short internodes and large leaves is produced, whichcovers the first clusters This type of growth greatly reducesthe amount of sunlight that reaches the clusters, does notallow proper airflow, and the humidity surroundinginflorescences will not dissipate. Consequently, the fruiton these clusters are more susceptible to blotchy ripening.

Other reports note that a potassium deficiency aggravatesthis problem, and in addition some varieties have beenfound to be more susceptible to blotchy ripening thanothers.

Blotches on fruit

Fruit affected by blotchy ripening

Reducing blotchy ripening1. Avoid planting during the cold autumn and winter

months, when days are short and cloudy and there islittle sunlight.

2. Raise greenhouse temperatures at night by heating.3. Apply sufficient nutrients with Potassium and maintain

the N:K ratio at 1:2 respectively.4. Ventilate the greenhouse and prevent accumulation

of excess humidity around the clusters and the ground.5. Avoid dense planting, which reduces the passage of

light and air between plants, especially on the lowerparts of the plant.

6. In late transplanting, use white PE mulching to increaselight reflection to the plants.

7. Remove leaves in order to allow penetration of sunlightto the base of the plant, when vegetation is dense.

8. Control irrigation and avoid over watering, especiallyin medium-heavy soil, by placing tensiometers in thesoil to determine correct irrigation times and quantity.

9. Avoid planting varieties that are susceptible to blotchyripening.Discoloration - Blotchy ripening

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Diameter (mm)

50-57

57-62

62-67

67-77

77-82

more then 82

HarvestingFruit destined for the fresh market, or fruit that is consideredto be choice grade, has to be of high quality, without flawsand without bruises. Fruit damaged by bruising andperforation during harvest is not immediately detected inthe packinghouse. Damage marks, excessive softnessand even rotting only appear after shipping, when the fruitis marketed. In order to avoid damage to fruit it is importantto be extremely careful during harvesting and grading.

Quality and standardsThe following table indicates the recommended fruitdiameters (in centimeters) for grading of single tomatoes,in accordance with local and export market demands.

Table 20. Export market and local market sizes andmarkings for packaging

29 TOMATOHARVESTINGANDPOSTHARVEST

When packing, the smaller fruits are packed in two or threelayers, while the larger fruits are packed in one or twolayers.

Quality requirements for grading tomatoes1. Characteristics of variety2. Uniform shape and size3. Uniform color4. Firm, with long shelf life5. No puffiness (hollow fruit).6. No blotches and discoloration7. Fresh stems and calyx8. Clean of dust and pesticide residue9. Short zippers on the fruit10. No mechanical damage11. Free of diseases and pests12. Good taste and improved flavor

Recommendations1. Fruit should be picked at the proper stage of ripeness,

cor respond ing to market requ i rements .2. Fruit should be picked during the cooler hours of the

day. Morning picking should be after condensationon plants and fruit dries up.

Name

Small

Medium

Large

Extra large

Giant

Super-Giant

3. It is advisable not to pick the fruits when temperaturesare high. Fruit that is picked at high temperaturessoftens quickly and is of poor quality.

4. Fruit should be picked into special containers, basins,cartons or crates that are padded with a double layerof plastic film to prevent pressure.

5. Picking containers should be dry and cleaned of allsand and plant debris.

6. Picking containers should hold only two layers ofpicked fruit. Fruit in the bottom layer should beplaced with stems facing downwards and fruit in thetop layer should be placed with stems facing upwards.

7. It is recommended to use picking trolleys that holdthe containers and can maneuver between the rows,to increase efficiency of the picking process.

8. The filled containers should be placed in a shadedarea to avoid overheating of the fruits.

9. Picking frequency depends on the rate of ripeningand color development. Tomatoes usually need tobe picked every two to five days, depending on thetemperature and ripening rate.

10. Care should be taken to avoid shaking the fruit whentransferring to the packinghouse because of themechanical damage that may occur.

11. Care should be taken to prevent mechanical damageto the fruit during the grading and packing process.

Picking trolley for picking between rows

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Grading and PackingThe fruit is marketed in various sizes, according to theirdiameter. Each size is packed into separate cartonsmarked with the size and weight. Size grading is performedmechanically on a grading table. The various sizes aregraded into separate compartments by setting the heightof the grading table rulers (accordingto diameter) or by weight. Qualitygrading is manual: fruit that is not suitablefor marketing is removed as it movesalong a conveyor. During qualitygrading, damaged fruit, fruit withblotches, uneven color, irregularity,puffiness and sand or spray residuesare removed. The high quality fruit isthen packed into the various cartonsthat are weighed and marked accordingto their quality.

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Stages in color developmentof tomato fruitThis illustration shows the development of tomato fruitcolor, from the mature green stage (1) through to the fullred stage (12). The tomato fruit reaches its maximum sizeat the mature green stage, when the chemical processesbegin, as presented in the Changes Graph on page 7.The most important stage is the start of color developmentat the turning point. The mature green stage can berecognized in fruit that set and develop after pollination bythe condition of the parenchyma tissue attached to thepericarp that coats the seeds. When a tomato fruit is cutwidthwise with knife and the seeds are also cut, thisindicates that the paranchyma tissue is stable and the fruitis not yet ripe. On the other hand, when a ripe tomato iscut widthwise, the seeds cannot be cut through, since theparenchyma tissue has changed, forming a mucous-likesubstance around the seeds and protecting them with itsglutinous property.

Simple grading table

System for grading cherrytomatoes according to color

and diameter

Lift on a cherrytomato grading table

Harvesting and handling cluster tomatoesAlthough cluster tomatoes are considered to be a topquality product, they are vulnerable to jostling, and thereforethe option of incorporating final packaging during thepicking process should be considered. This process couldalso be laborsaving.

1 - Green mature 12 - Full red

Green and mature fruits

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One of the possibilities for packing during the pickingprocess is to use picking trolleys equipped with packagingfor export. The trolleys will also have containers for fruitthat has to be removed from the clusters for various reasons,such as cracked fruit (usually the first fruit on the cluster),small fruit at the end of the cluster, and other damagedfruit that is unsuitable for marketing.In addition to removing the unsuitable fruit from the clusters,it is necessary to make sure that the rest of the fruit on thecluster is free of dust and pesticide residue and thereforea small soft brush for cleaning fruit during picking shouldbe part of the equipment. After cleaning the cluster, it isgently laid into the export carton. The cartons are finallyweighed in a shaded area in the packing shed.An alternative possibility for packing is to pick the clustersinto larger containers on picking trolleys that run on aconveyor that moves between the rows. Handling, suchas removal of unsuitable fruit, cleaning off dust and pesticideresidue, packaging and weighing, is performed in thepacking shed.

Cleaning systemsIt is recommended to wash cluster, regular and cherrytomatoes after harvest, in order to remove dust particles,chemical residue and soil, and to minimize spread ofdiseases. There are two main systems for cleaning fruitbefore final packing.

1. Cleaning dust off clusters by brushingIn order to clean dust from the tomato clusters prior topackaging, it is necessary to construct a device (cleaningstand) suitable for cleaning cluster tomatoes of varioussizes (large, regular, cherry) without damaging the fruit.The device should contain two brushes placed horizontallyadjacent to one another and that rotate in oppositedirections. The bristles should be very soft and gentle toavoid scratching the fruit and dropping them from theclusters during cleaning. The bristles should be of nylonfibers in rows of varying heights, so that the brush appearsto be stepped. The brush diameter should be about 290mm with embedded bristles. The brushes should rotateat a speed of about 80 rpm.It is recommended to build a double cleaning stand foreasy and speedy operation. The motor and operatingsystem are usually placed in the center of the stand whiletwo sets of brushes operate on either side. The fruit-filledcontainers coming in from the field should be placed abovethe cleaning stand for easy access during cleaning.Cleaning is performed by holding the cluster between thefingers at the end of the cluster stem and “dipping”it between the brushes two or three times. The cleancluster is then placed on a moving round table close by.This table is used to collect the cleaned clusters andperform additional cleaning if necessary, and therefore thework surface should be large enough (the recommendeddiameter of the table is two meters). A container shouldbe placed under each set of brushes to collect any fruitthat may fall during cleaning. At the end of each day, thebrushes and packaging apparatus should be cleaned andprepared for the next day.

2. Washing machines for cleaning cluster, regular andcherry tomatoesWashing machines for cleaning cluster tomatoes have afeeding belt, rinsing compartment (with spray nozzlesinstalled above and below the conveyor belt) and aconveyor belt with fans for drying the fruit. The washingmachines are differentiated mainly by the structure of theconveyer system, which transports the trays or clustertomatoes.The machine for washing trays is suitable for 40 x 60 cmtrays. The trays are fed widthwise, and therefore thesemachines are at least 60 cm wide. Machines that areused for individual clusters have different widths, varyingfrom 50 cm to 1 m, according to the required output andthe daily volume of fruit.One worker is needed to feed the plastic trays, while twoworkers are needed to feed individual clusters.A motor adjusts the speed of the conveyor belt, so thatwhen the cluster tomatoes are removed from the washingmachine, the drying action is also completed (althoughcomplete drying is not necessary).The different machines are similar only on the outside.Length is determined by the following parameters:- Feeding section: up to one meter- Closed washing compartment: about 1.2 m long- Drying section: up to 5 m longThe washing system has two nozzles systems (upper andlower). It is important to use full cone nozzles with bigdroplets (over 300 micron) to ensure the wetting andcleaning of the clusters.There is a water-collection tray system at the bottom ofthe machine, which drains the dripping water and enablesrecycling of water used for washing.A filtration and sterilization system, (using chlorine) whichis integrated into the collection tank and pump, is requiredfor recycling this water.The recycling system can be adjusted as needed, accordingto the water volume used for washing and according tothe number of daily work hours.When choosing a machine for washing trays, it is importantto take into account the size of the general area, theharvest intervals and the quantity of planned harvest, andto ensure there are sufficient trays.At least 200 trays are needed for one ton of pickedtomatoes.Do not use hot water for washing. The water shouldbe the temperature of the water pipe.

Cleaning clusters by brushing

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Packaging house with washingand grading machines.

Packaging systemPacking is mainly performed after the washing machine.Other components, which complement the system, include:a conveyor belt, along which packing is performed atindividual work stations; a gravitational or motorized rollerconveyor to box the full cartons; and a weighing stationfor weighing and palleting the full cartons.Although the packing line is simple and short, it is importantto plan the packing house to ensure optimal exploitationof the area and to achieve efficient work.It is recommended to position the packing conveyor beltdirectly after the washing system. Each worker shouldhave an organized work station on which the packingcarton is placed. The full carton is transferred to thegravitational or motorized roller conveyor. The conveyorfor empty cartons (new) is above the roller conveyor.A weighing station at the end of the roller conveyor isimportant. When packing cluster tomatoes, the cartonsoften weigh more than necessary. Payment is not receivedfor surplus addition, and therefore it is important to use astable and level electronic scale, which is accurate to 10grams.Packing systems for cluster tomatoes are suitable for alltomato varieties: cluster, cherry, midi, baby and regulartomatoes.

Coarse spraying - pesticide residue

Green shoulders

Irregular fruit

Gold speckles

Malformed - Cat face

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Mechanical damage and perforations

Direct sunlight and sun burn

Zippering ( Sutures )

Effect of sun burn internal view

Blossom-end rot

Crack injury

Chilling injury

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Improving the quality of tomato fruit1. Climate: ensure appropriate temperature by heating

and cooling as needed to prevent frost damage, improvecolor and ensure a continuous and reliable supply.

2. Controlled irrigation and fertilization prevents hollownessand blotchy ripening, improves color, increases firmness,extends shelf life and improves taste (by increasingthe fruit sugar level).

3. Gentle handling during the harvesting, grading andpacking processes prevents bruising, damage fromstems perforating other fruit, and mechanical scratches.

4. Appropriate foliage-fruit ratio protects the fruit from frostdamage in winter and sunburn caused by direct sunlightin summer.

5. Removal of excess humidity from the greenhouseimproves growing conditions, reducing appearance ofblotchy ripening and micro cracking and minimizingdevelopment of diseases.

6. Better fruit set improves shape uniformity and reducesfruit puffiness.

7. Better penetration of sunlight by cleaning roofs in winterreduces puffiness, increases yields and improves color.

8. Shading in summer prevents sunscald and greenshoulders. It also prevents fruit turning white inside,especially around the pericarp tissue or from the stemtowards the center, along the walls between the carpels.

9. Growing tomatoes in a soilless culture improves theshape and color.

10. Fine spraying with the correct nozzle and at the propertime reduces chimical residue and prevents diseaseand rotting during shipment.

Storage of tomato fruitsThe optimal temperature for storing tomatoes for periodsof 10 to 14 days is 10-12ºC. Varieties that are known tohave a long shelf life are suitable for storing under theseconditions, while varieties lacking firmness should be soldimmediately after harvesting.Storage at 10º-12ºC has var ious purposes:

To store fruit after packing until shipping to the market.This period is usually from a few hours to a few days.To refrigerate fruit during land and sea transportationto distant destinations.

The storage method and the color at harvesting both affectthe storage period suitable for tomatoes. For example,when the harvested tomatoes are in color they can bestored for longer, while fruit harvested at a more developedcolor stage can be stored for shorter periods. If the fruitis harvested at a more advanced color stage, it can bestored at a lower temperature, for example 10ºC.In general, tomato fruit can be stored for two to threeweeks, depending on the ripening stage at harvest.When stored for an extended period, fruit may start to rot.Therefore the various packages have to be resorted afterthe storage period and before marketing, to remove anydamaged or rotten fruit.Fruit is not usually refrigerated at 12ºC before grading andpackaging since condensation forms on cold fruit once itis removed from refrigeration. It is therefore preferablethat fruit be kept in a cool packing shed after beingharvested. It is important to ensure that the fruit is gradedand packaged within a short period, and that the packed

product is quickly stored at 12ºC.The relative humidity recommended for storage is90-95%.

Onset of rot during storage

Spread of rot

Etheral is a commercial product containing 48% ethephon(2-chloroethyl) phosphoric acid that accelerates the ripeningprocess when coming into contact with fruit, by increasingthe production of plant ethylene. Israeli studies have foundthat fruit treated with Etheral ripen and become red quickerthan untreated fruit.General review and findings of studies:

Mature green processing tomatoes that were dippedin a 1,500-3,000 ppm Etheral solution ripened to fullred in 12 days.Etheral sprayed on foliage of processing tomatoesworks well when 25% of the yield is beyond turningstage. The suitable dosage is 30 gm active ingredientin 50 liters water per 0.1 hectare.

ETHERALTREATMENT TOACCELERATETOMATORIPENING

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Eighty percent of mature green tomato clusters in agreenhouse sprayed with a 0.4% Etheral solutionripened within 11 days, compared to only 67% in theuntreated plots.In a greenhouse, ripening was accelerated in 88% ofmature green tomatoes that were picked seven daysafter their shoulders were brushed with a 0.5% Etheralsolution, compared to only 12% in the untreated plots.In a greenhouse, ripening was accelerated in maturegreen tomatoes four days after cluster stems werebrushed with a 6% Etheral solution. 61% of the fruitripened compared to 41% in the untreated plots.

Etheral treatment is not common in regular tomatoproduction in Israel although it is used in various placesaround the world to accelerate ripening. It is used inprocessing tomatoes, to accelerate ripening of fresh markettomatoes when the price is high and to accelerate ripeningin greenhouses at the end of the season. Spraying Etheralon plants causes leaves to dry up and can also causemuch damage to the plants. A combination of hightemperature and high concentration of Etheral solutionaffects the severity of the damage.

IntroductionThe growing awareness of health and environment, togetherwith the demand for uncompromising quality of organicproduce requires the use of advanced technologies whengrowing organic tomatoes. This combination has resultedin a growing system which meets the requirements of allorganic standards, while producing a high quality andquantity yield. The produce is free of pesticide residueand the production method encourages re-cycling of wasteand improves the quality of the immediate environment.Production is user-friendly and contributes to the immediateenvironment.Production of organic tomatoes in greenhouses requiresa long-term commitment, attention to small details,performance of tasks on time, and a long-term view.Growers and field extension staff tend to test a crop by itseconomic performance in a single growing season. Whilethis may be feasible with a regular crop, with organicproduction the crop results should be tested over a longerperiod.

31 OVER VIEWOF ORGANICPRODUCTIONOF TOMATOES

Organic standards and inspectionModern organic agriculture should adapt itself to the localorganic standard and to the standard of the target markets. In Israel, produce should be grown according to the Israeliorganic standard, while adapting to the requirements ofthe European standard - EU 2091/92 Directive - if it istargeted for the European market, and the National OrganicProgram (NOP) of the United States Department ofAgriculture, if it is targeted for the USA market. Somemarkets also require approval from the InternationalFederation of Organic Agriculture Movements (IFOAM).Organic production should be inspected by a certifiedinspector for the organic standards in the target marketand the regulations and standards in the source country.In the organic greenhouse, only materials and technologiesmeeting the approved standards and checked by thecertified inspector may be used. Approval by a certifiedinspector constitutes reliable evidence that the productthat is marketed as organic does indeed meet the organicstandard for that market.

Agrotechnical aspectsIn principle, there are no significant differences betweena greenhouse for organic production and regular tomatoproduction. It is important to maintain complete sealing byusing an insect-proof net, and the greenhouse shouldhave a double entrance to prevent penetration of insectsinto the greenhouse. The greenhouse should be coveredwith IR and UV blocking plastic to reduce the activity ofwhitefly and aphids. In the Arava desert in southern Israel,tomatoes can also be grown in net houses.

Soils, Soil fertility and crop rotationIn the organic greenhouse, crops must be planted in thelocal soil. All organic standards prohibit growing in soillessculture. In order to produce a successful crop, properconstruction of the soil fertility should be ensured, as aprincipal component of nutrition for the crop and for controlof weeds and soilborne diseases.

The main component in soil fertility in the greenhouse isapplication of a generous volume of quality compost.The compost quality is important, and there should be nocompromise on well-prepared compost which hascompleted the process of rapid decomposition and wasleft for a further ripening period, in which positive micro-organisms develop. These micro-organisms createresistance to the establishment of soilborne diseases andserve as a major substitute for soil sterilization. Thecompost should be at the same temperature as theenvironment when ripening, in which it does not heat upeven if wetted or turned over. It should be free of weedseeds and vectors of pathogens. It is recommended tospread the compost over the greenhouse surface and tocover it with the upper soil layer. In the first years, arelatively large amount of compost is spread out, whichdecreases with the development of soil fertility. Theamount of compost stems from the condition of soil fertilityand is based on accumulated experience in the area andthe condition of the plot’s fertility. The compost should be

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moistened at least two weeks before planting to ensurebiological activity.

If possible, it is recommended to sow a soil-improving cropsuch as legumes or cereals in the greenhouse beforeplanting tomatoes. The type of crop is determined accordingto the season and time available for growing the crop inthe greenhouse. Short-term crops, such as millet alsohave a positive contribution to soil behavior. A soil-improvingcrop or intermediate crop may serve as a partial substitutefor crop rotation, which is difficult to apply in organicgreenhouses due to the limited variety of crops that canbe grown.

One of the basic requirements of organic production is thedesire to apply full crop rotation of a range of crops fromdifferent families in the organic greenhouse. It isrecommended to integrate crops from the Cruciferae family,such as cabbage, cauliflower and broccoli betweensolanaceous crops. It is important to bury the crop debrisin the greenhouse. If this cannot be performed for economicreasons, intermediate crops should be integrated for greenmanure.

Irrigation systemA drip irrigation system is recommended, with two driplaterals per bed and close dripper spacing. The drippersshould have a relatively high discharge and should beresistant to clogging by organic nutrients applied throughthe irrigation system. The irrigation system should be wellplanned for uniform distribution of water over the entiregreenhouse area. A collection pipe should be installed atthe end of the laterals, to allow easy flushing of the drip-lines to remove any accumulated nutrient material.

VarietiesThese should be selected according to conventionalstandards in the region and according to marketrequirements, especially for export markets. In most cases,the conventional varieties are also compatible with regularagriculture. Multi-resistant varieties are recommended,especially those that are resistant to soilborne pests, aswell as show resistance to viral or leaf diseases. Graftedplants may also be considered in nematode-infested plotsif there is no suitable variety that is nematode-resistant, orresistant to other soil-borne diseases.

Preparation of greenhouse for plantingThe greenhouse should be sealed and cleaned of weedsand crop after-growth at least two weeks before planting,to prevent establishment of pests in the greenhouse. Ifthe soil fertility is low, feather meal can be added to enrichthe soil with nitrogen. If feather meal is added beforeautumn planting, care should be taken to avoid excessnitrogen in the soil, which may damage the young plants.During this period, irrigation should be applied and the soilshould be kept moist, to ensure proper microbial activityin the compost. It is recommended to hang up yellowsticky traps and to wrap greenhouse posts and coveringswith yellow sticky film to trap whitefly, and with blue stickyfilm to trap thrips.The greenhouse should be brought to biological balance

by crop rotation, intermediate crops, green manure anduse of good compost. If nematodes or pathogenic soilfungi have developed in the greenhouse, it is recommendedto integrate soil solarization. In particularly severe cases,it is recommended to consult a field extension specialistand to consider steam sterilization or use of grafted plants.

PlantingBefore planting, weeds that germinated in the greenhouseafter application of compost should be removed by lightplowing or raking. The seedlings should be protected fromBemisia tabaci (whitefly) from the time that they are removedfrom the nursery until they are brought into the greenhouse.It is important to ensure that the greenhouse is sealedduring planting. Before planting, the plant’s root plugshould be saturated with water. If the plug is dry, it isimportant to wet it before planting, by dipping it in water.The seedling should be planted in moist soil with plantingholes dug by hand or with a planting pick. The seedlingshould be placed in the hole and the soil around it shouldbe gently pressed down.

Post-planting activities in the greenhouseAfter planting, it is important to irrigate lightly and to continuewith light irrigation until white shoots develop from the plug. When the shoots develop, irrigation intervals should bespread out to the maximum, without causing damage tothe seedlings. These irrigation intervals encourageestablishment of a large root zone and prevent lack ofaeration in the soil. Lack of aeration encourages wiltingdiseases and accumulation of nitrites, due to terminationof the nitrification process as a result of oxygen deficiency(nitrite is toxic for plants).

Fertilization and irrigationAt the beginning of growing, irrigation is applied withoutnutrients. The soil in the organic greenhouse is rich innutrients from the compost and feather meal. Cropdevelopment does not need to be encouraged too muchbefore fruit set, to avoid development of a plant which istoo large and vegetative. In regular agriculture, wherecompost is not applied, it is customary to apply moderateamounts of fertilizer. When the plants develop, it isrecommended to consider addition of approved organicfertilizer near the drippers, or application of liquid organicfertilizer through the irrigation system, according to theplant’s appearance and the fertility of the soil. Fertilizershould be applied carefully and excess fertilization shouldbe avoided, as it may encourage damage and lead tounbalance in the plant. The types and quantities of fertilizersare determined by their accessibility, the condition of theplants and the fertility of the greenhouse. Therefore theyare adapted to the time and place and it is not possible toprovide an accurate growing recipe.

In Israel, it is conventional to use solid guano or guanoextract (bird manure from Peru or Namibia) and fermentedcow manure, which is approved by certified inspectors.Soil-improving elements can also be added, such as aminoacids and microelements approved for use in organicagriculture.

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Plant protectionLeaf diseases and pests are controlled according to organicstandards in the season and area, while striving to createoptimum conditions for growing and poor conditions forthe pest or fungus. Creation of a biological balance ispreferred, and if intervention is required, mass trapping ordisorientation is recommended. When there is no othersolution, pesticides approved for use in organic agricultureare applied. When pesticides are applied, it isrecommended to use substances and methods that do notharm natural enemies.

Principal pests and possible solutionsin organic agriculture

Tomato yellow leaf curl virus (TYLC)Control is by sealing greenhouses with a suitable screen,hanging yellow sticky traps, covering poles and greenhousecoverings with yellow sticky film and application of approvedsubstances, such as LQ215 detergent combined withAzadirachtin, which is the active ingredient of neem seedextract. When using these substances, it is important toensure that they are included in the list of materials approvedfor use in organic agriculture, which is updated periodicallyand published on the website of the Ministry of AgriculturePPIS department Israel or other local certification body.It is recommended to remove contaminated plants fromthe greenhouse.

Russet miteThis pest can be controlled by powdering, spraying orvaporization with approved sulfur materials, preferablyliquid sulfur, which are less harmful to natural enemiesand to the plastic covering the greenhouse. Sulfuricvaporization can also be considered, with a lower applicationper hectare and operation of 4 hours at night. Care shouldbe taken when applying sulfur when bumblebees are usedin the greenhouse for pollination. Sulfuric treatment is alsoefficient for control of powdery mildew.

Late blightIntegrated control is required for late blight, includingsanitation, removal of lower leaves and contaminated leaves,spraying with approved substances and maintenance oflow humidity. In humid regions, it is recommended toconsider covering soil with plastic to reduce the humidityin the greenhouse. The recommended method today iscombination of neem oil with approved copper substances. Use of copper may be prohibited soon, and efforts arebeing made to find an efficient substitute. It is recommendedto consult with a field extension specialist for informationon control of other pests.

PostharvestWhen harvesting, sorting and packing, it is recommendedto maintain proper conditions for preserving the fruit qualityand to apply conventional treatments, such as hot brushing,which is also suitable for organic fruit. However, othertreatments are prohibited, and therefore special care shouldbe taken to ensure sanitation in all handling processes.

Organic production is a way of life, requiring long-termcommitment, and is not just another production method.Organic production is still developing, and therefore it isrecommended to work together with field extensionspecialists researchers and experienced organic growers,who are familiar with the subject of organic agriculture, inorder to achieve crop management which is compatiblewith the time, place and grower.

Tomato plants are susceptible to many diseases and pests,some of which affect numerous other crops and some ofwhich are specific only to tomatoes. Tables describingthe various types of damage according to their specificgroups appear below.Pest control is a significant part of tomato production costs.In recent years, efforts have been made to reduce the useof pesticides for various reasons:1. Saving in production costs2. Prevention of toxic residues on fresh produce and in

foodstuff3. Prevention of air pollution and environmental damage

Pest control methods are divided intogroups:1. Conventional pest control: the application of chemical

pesticides as routine preventative treatment (proactiveapproach), and then following the appearance of aparticular disease or pest.

2. Agro-technical methods which are complementary toor are an alternative to chemical pest control. Thesemethods include physical protection of crops usingspecial greenhouse coverings such as special plastics,nets (insect proof), double doors, soil mulching andclimatic manipulation to minimize conditions for thedevelopment and spread of insects and diseases, soilmulching reduce conditions for development of leafdiseases. Solar sterilization of the soil and greenhousespace is now a common and widely used method. Inaddition there is steam sterilization which is limited tosubstrates and light soils.

3. Biological pest control: Using predators to controlinsects and colored sticky traps that attract insects, inorder to monitor and reduce the insect population.

4. Genetics: Growing varieties that are resistant or tolerantto specific diseases and the use of rootstocks toprevent soil-borne diseases.

32 DISEASE ANDPEST CONTROL

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Undoubtedly, these auxiliary means are beneficial and areintended to reduce the use of chemical pesticides.Nevertheless, the application of chemical pesticides is stillthe most commonly used and important method forprotect ing plants f rom pests and diseases.Details of the recommended chemical preparations canbe found in the booklet “Recommendations for Pest Controlin Vegetables”, published by the Agricultural ExtensionDepartment of the Ministry of Agriculture and RuralDevelopment in Israel (published in Hebrew).

Sanitation of greenhousesand surroundingsGreenhouse crops should not be planted unless thegreenhouse has undergone suitable preparation to includesterilization of the soil or soilless culture media. Cleanthe greenhouse of refuse, and ensure that the waterdrainage system in the greenhouse is operating properly.

All remaining stalks, leaves and fruit, as well as all theweeds inside and outside the greenhouse, which couldhost diseases, hide pests, and prevent proper airflow,should be removed from the greenhouse. It is extremelyimportant to ensure good ventilation and hence a goodenvironment for healthy plants.The following cleanup process is recommended forgreenhouses at the end of a crop and before planting anew crop:

At the end of the crop, the plants should be pulled outof the soil. Every effort should be made to remove allparts of the plants, including as much of the root systemas possible.

In soilless culture, where large containers such as longpolystyrene tubs are used, it is easier to remove theplants with their root system after they dry out slightly.In other containers such as buckets or bags, the plantstems should be cut as close as possible to the substratesurface.

The plants should be removed whole, and unnecessaryshaking should be avoided to preventspreading sporesor broken off parts of diseased plants. The plants thathave been removed should be collected and destroyedby burning in a remote area that is not intended foragriculture and is not close to residences.

Before replanting and after preparing the greenhouse,a basin or tray containing a foam mat soaked in a 3%chlorine solution, should be placed at the entranceto the greenhouse. This device is for cleaning shoesevery time anyone enters the greenhouse, to preventthe recently sterilized soil becoming contaminatedwith pathogens (which cause soil diseases). Everytime the foam dries out, it should be re-soaked withthe solution.

Yellow sticky trap for insect monitoring

P. persimilis - spider mite predator

Diglyphus – leaf miner predator

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Clean healthy environment

Materials for plant protectionThe use of plant protection materials in tomato productionfor the export and local markets are su bject to the directivesof the target markets. Pesticide residue on fruit is examinedin Israel and abroad, and the fruit is rejected if residues ofprohibited products or levels higher than those permittedare found. Instructions regarding these subjects arepublished every year in many countries and in Israel bythe Plant Protection Department of the Ministry of Agricultureand Rural Development (in Hebrew).Lists of products permitted for use on tomato crops arefound in these publications. Information is also includedregarding the number of days a specific chemical can beused before harvesting. This is based on the assumptionthat the material will begin to break down over this periodand that the residue level will decrease to non-harmfullevels.

Pesticides are applied to greenhouse tomato crops aspreventative measures and as reactive treatments to stopinsects from spreading and to prevent establishment inthe greenhouse of any type of pest that might cause director indirect damage to the plants.Most commonly used pesticides are marketed in variousforms, such as soluble and suspendible powders, solublegranules, concentrated suspensions, emulsions and liquidsolutions.Pesticides are usually applied to plants by spraying. Theplants should be sprayed in such a way that the solutionreaches all parts of the plants, entirely covering the foliage,to ensure total control of all pests and pathogens on thevarious parts of the plants.Pesticides are usually applied in small quantities per plotand it is difficult to spread them evenly in their marketedform. To ensure even distribution on foliage and to preventdamage to plants, the various pesticides are diluted andmixed with water, separately or in combinations. Thisdepends on the type of damage the chemicals are meantto prevent, the sprayer volume and size of plot to besprayed. Directions for use appear on the packaging foreach product, indicating quantities of solution to be usedper plot size, and these recommendations should befollowed.Various methods and types of sprayers are used to applypesticides. The different types of sprayers have diverseactions, droplet size and volume requirements in order toobtain the best results.

Pesticide applicationmethods for greenhouses1. Motorized backpack sprayer: operated by a gasoline

motor. The motor activates a blower that drives highvelocity air (more than 80 m/sec) through the sprayhose and nozzles. The solution is delivered throughthe nozzles to the plants in tiny airborne droplets. Thesize of the droplets ranges from 50 to 200 micron.Motorized backpack sprayers are considered the mostimportant greenhouse pesticide application tool.

33 CHEMICAL SPRAYAPPLICATIONTECHNOLOGIES

Motorized backpack sprayer

Poor sanitation – source of diseases and pests

Poor sanitation

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The volume of solution in this spraying method is 500- 800 liters per ha. of mature plants. The operatorsof this type of sprayer carry the sprayer on their backand hold the spray gun in their right hand while the lefthand gradually activates the fuel lever to its maximumposition when starting to spray. The worker first opensthe valve for the fluids and then directs the spray guntowards the plants in such a way that the airflow reachesthe plants 3 meters ahead. The spray height shouldbe directed towards the middle and upper plant partsand the hand and nozzle kept level and steady. An“up and down” hand movement should never be used.

2. Fixed greenhouse sprayer: usually positioned outsidethe greenhouse and attached to it by a system of pipesfixed along the length of the greenhouse. The pipesystem includes valves with quick couplings forconnecting to a flexible hose that is attached to thespraying mechanism, either a spray gun or a mobilevertical spray-pole. The sprayer tank is fitted to apump that operates according to various factors suchas pressure, flow and rpm. Minimum 30 atm. pumppressure is required and flow capacity required ingreenhouses is 60 l/min. The fixed pipe system usuallyconsists of half inch galvanized tubes and has valveswith quick couplings for connecting the flexible hose,fitted along the length, and a valve for cleaning anddraining the pipe system fitted at the end. A portionof flexible pressure hose should be connected betweenthe fixed pipe system and the tank, to prevent the tankfrom being damaged when the sprayer vibrates. Themobile hose is usually a 3/8 inch flexible hose able towithstand 40 atm. The length of the flexible hoseshould equal the length of the row, plus half the distancebetween the row and the valve fitted to the fixed pipes.The spray gun for greenhouses is operated by a valvethat is also the handle.

The spray gun handle can be fitted to a vertical polemade of sections of thin, lightweight tubing that enablenozzles to be attached at 25-30 cm spacing. Thebottom of the spray-pole should be 20 - 30 cm fromthe ground with the option of fitting two nozzles at thebottom to cover the lower parts of the plants. Theheight of the spray-pole should be according to the

Sprayer tank

The conventional solution volume for this spray methodis 500-1,200 l/ha of mature plants. During spraying,the operator activates the spray gun and directs it upand down to ensure complete coverage of the foliage.This action is usually performed by holding the spraygun in the right hand and spraying the left side whilewalking up the row and repeating the operation whilecoming back down the row. The operators pace shouldbe 1.5-3 km\hour. On the other hand, in order to avoidgetting wet from the spray pole and the sprayed plantswhen spraying with a vertical spray-pole, it isrecommended that the operator walks up to the endof the row with the spray-pole and then operates it byopening the activation valve while slowly walkingbackwards back down the row.

3. Air sprayers: Israeli manufacturers have recentlydeveloped several types of sprayers for sprayinggreenhouses with air. The principle of the method isto force the solution out of the sprayer with the aircurrent. This action turns the leaves, so that both topand bottom sides are covered almost equally. The

plant height, with the option of extending and addingnozzles when needed as the plants grow.A single or double adjustable spray-tip nozzle is fittedat each spray junction. A quick coupling should beconnected to the spray-pole to attach it to the solutionsupply hose. The spray-pole is connected verticallyto the centre of a two-wheel trolley with a handlebar.The width of the wheels should enable easy passagealong the paths between the rows. The trolley shouldbe fitted with a coupling for a flexible hose, an activationvalve for operating the spray-pole and a pressuregauge similar to the one attached to the spray gun,so that the true spray pressure can be seen. A flexibletube is also necessary for the flow of solution from thegauge to the spray pole.

Vertical pool of nozzles

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spray nozzles suitable for this method are elbows orspray system nozzles, which are hollow cone nozzlesthat generate the required pressure of between 5-10bars.The air sprayers are narrow vertical sleeve boomsprayers and track-driven greenhouse sprayers.A width of 70 cm between rows is required for thisequipment. Narrower equipment (60 - 64 cm has alsobeen developed, such as, sleeve sprayers and boomsprayers) . This spraying method is more efficientthan the other methods.

Air sprayer

4. Low volume sprayers: Cold foggers in greenhouses.In the search for more efficient greenhouse chemicalspray application methods that are both labor savingand minimize the use of chemicals, new technologiessuch as foggers that dispense cold fog have beenintroduced. Fogging disperses chemical spraythroughout the greenhouse without the operator beingpresent. This technology is based on two consecutiveoperations: creating aerosol (tiny droplets, less than20 microns) and distributing it throughout thegreenhouse atmosphere with the regular air currents.The aerosol created by the cold fogger does notrequire the pesticides to be heated to high temperaturesand therefore a very wide range of products can beused with this form of application.

A small volume of solution is required for fogger application,10 liters per ha. is sufficient. Recent experiments showthat distribution is more even when circulation fans operateinside the greenhouse during the fogging process. Pesticideapplication by cold fog requires the use of equipmentapproved by the Institute for Agricultural Engineering. Aircurrents easily carry the tiny droplets (5 - 25 microns)through any tear or hole and are liable to pollute the outsideenvironment, causing possible harm to people, animals,and even to other plants. Therefore, to prevent pesticideclouds from escaping to the outside atmosphere, it isessential to ensure that the greenhouse is completelysealed while operating a fogger. It is recommended tofog in the late afternoon or evening. The greenhouse canbe reopened three hours after the fogging process hasbeen completed.

There are many flaws and disorders in tomato fruit andplants that are not caused by insects or pathogens. Someof these disorders appear on the plant foliage and/or onthe fruit. These disorders usually cause damage to fruitquality as well as to the yield.These non-pathogenic disorders are affected mainly byclimatic conditions and by agro-technical methods whichencourage their appearance. The table below presents ageneral review of the non-pathogenic disorders in tomatoproduction.

34 NON -PARASITICDISORDERS

Cold fogger

Air sprayer

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Table 22. Non-parasitic disorders

Blossom-end rot

Light tan, water-soaked lesion spot at the baseof the fruit that grows and usually turns blackand leathery.

All year round

Regular irrigation; balanced fertilization;correct calcium concentration; usevarieties tolerant to BER.

Goldspeckles

Golden spots around the calyx and on the fruitshoulders that usually spoil the externalappearance and cause the fruit to softenquickly, thus reducing shelf life. This is anaccumulation of calcium oxalate crystals in cellsunder the epidermis.

Winterandspring

Use varieties tolerant to this condition.Proper levels of nitrogen and generalplant nutrition.

Fruitcracking

Micro, Radial and Concentric cracks.Cracked fruits are not suitable for marketing.

Spring,summer andautumn

Tolerant varieties, proper fertigationprogram to prevent succulent plants, limitfruit exposure by encouraging leaf coverof fruit, reduce humidity

Chillinginjury

Glassy or watery marks on the fruit. Plant foliagebecomes purple or black and dries up.

Winter whentemperaturesdrop below6oC

Prevent chiling by heating thegreenhouse. In addition ensure good aircirculation. Use IR thermal plasticcovering.

Nutritionaldeficiencies

Generaly yellowing leaves and a typicalelement deficient.

All year round Adding the deficient elements, usuallyiron, magnesium and manganese;avoiding deficiency by proper nutrition.

Phytotoxicityof chemicals

Leaves or other parts of the plant appear burnedby fertilizers or chemical sprays.

All year round Use correct dosages of chemical andfertilizer sprays; only use recommendedchemical combinations.

Diease

Sunscald

Damage

The part of the fruit that is exposed to directsunlight becomes yellow or white.Varieties with green shoulders are moresusceptible.

Season

Summerandautumn

Control

Prevent fruit that has been shaded fromsudden exposure to the sun.The greenhouses should be shaded orwhitewashed during the risky seasons.Grow thick foliage to protect clustersfrom being exposed to direct radiation.

Silvering Sudden change in the leaf color, starting withparts of the leaf turning silver and spreading tothe whole leaf. The fertility of these plants isreduced and fruit does not form. Incidents ofsilvering and symptoms appear under poor climateconditions, as a combination of low temperaturesduring the days (below 180C) and a lack ofradiation.

Poor climateconditions

Avoid sensitive varieties; leave sideshoots as thay may not show thesymptoms. Replace by growing sideshoot of the neighbor plant.

Puffiness(hollow fruit)

Fruit shape is usually distorted, appearing flatsided or angular; when cut spaces can be seenbetween the locules contents and the wallsof the fruit.

All year round Tolerant varieties; balanced fertilization;aviod excess irrigation; proper use ofgrowth hormones.

Winter Proper spacing between plants in thegreenhouse; cleaning roofs to improvelight intensity; heating during cold winter.

Blotchyripening

Gray - brown spots or stripes that are visible onthe skin as well as inside the fruit.The phenomenon is known as Brownwall.

Winter and Tolerant varieties; properfertilization, good light and removal ofexcess humidity; heating during coldwinter.

Spring

Zippering Thin brown necrotic scars from the calyx towardsthe base of the fruit, in different lengths causedby anthers being attached to overy wall.

Summer andautumn

Tolerant varieties; prevent stresscondition; extreme temperatures andexcess humidity.

Oedema Small bumps that split on the underside of theleaf and are caused by a combination of highhumidity and low temperature.

Autumnand winter

Good ventilation and reduction ofhumidity.

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Oedem on leaves

Table 23. Parasitic plants and other weeds that attack tomato plants

Disease

Orobanchespp

Damage

Parasitic plants cause direct damage totomato plants. There are different typesof Orobanche with typical flowers, whiteand purple.

Season

All year round

Control

Soil sterilization, avoid spreading seedson cultivation equipment; avoid grazingand entry of animals into the growingarea.

Cuscutacampestris

Parasitic plant, yellowish, clings to all partsof the tomato plant and causes it to distort.

Late spring,summer andautumn

Chemical herbicides; avoid spreadingseeds as above and through watersystem. Clean external greenhousesurroundings.

OtherWeeds

All kinds. Could germinate in greenhousesused for growing tomatoes and cause directdamage to tomato plants. Weeds are alsohosts for insects and diseases.

All yearround

Cleanliness - weeding the greenhousesurroundings; soil sterilization; use ofsoil mulching and herbicides.

Application of wrong material (chemical)

Silvering

Weeds are plants that grow in unwanted places atunsuitable times. Weeds cause damage to cultured plants,including tomatoes, in various ways:1. They compete for and deplete nutrients and water in soil.2. When weeds grow next to cultured plants, they undergo

rapid growth and elongation of the stem because ofcompetition for light. This causes the cultured plantsto weaken and reduces their yield.

3. Weeds are host to pests and diseases that are easilytransferred to cultured plants and contaminate themin various ways.

4. Certain weeds cling directly to the cultured plants andthereby deplete the moisture and nutrients in theplants causing them to weaken and eventually die.

Various ways to fight weeds:1. Mechanical eradication by tilling, plowing, and rotovating.2. Chemical eradication by soil sterilization such as Methyl

Bromide or selective use of herbicides.3. The use of opaque plastic film that prevents the sprouting

and development of seeds that lie under the plastic.

35 WEEDS ANDPARASITIC PLANTS

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Soil-borne diseases are usually caused by fungi andbacteria that can be sustained in the soil for years. Thedamage caused by these pathogens is severe and causesenormous financial losses. Contamination by some ofthese pathogens can result in young plants dying offimmediately after planting. Examples of this are thedamping off diseases. In older plants, there can be wiltingbefore or even during harvest, due to root rot or damageto the xylem vessels. In both cases, where both youngseedlings and adult plants are damaged, the yield loss isgreat in quantity as well as quality.Efforts are made to minimize these types of affliction asmuch as possible, based on the assumption that a constantnumber of plants throughout the season will guaranteethe potential yield per plant and the expected yield perplanting. Soil sterilization is the conventional method tocontrol these soil diseases. Crop rotation helps reducethe pathogen population while traditional genetic breedingdevelops varieties that are tolerant or resistant to thesediseases.Based on the assumption that in the future fewer pesticideswill be used and the fact that crop rotation is not possiblein greenhouse production, it appears that development ofresistant varieties is the most efficient method forsuccessfully fighting soil-borne pathogens. Successfulgenetically engineered disease-resistant tomato varietiesinclude resistance to Fusarium oxysporum f.sp. lycopersici,Verticillium dahliae, and Fusarium oxysporum f.sp. radicis,and the successful development of varieties that arepartially resistant to root-knot nematode that have becomevery common.Among the most efficient methods for controlling soil-bornediseases are soil sterilization (chemical and solar) andtraditional plant breeding for soil-borne disease resistance.In addition, another method that is gaining popularityinvolves grafting desired variations onto a suitable rootstockthat has the appropriate range of disease resistance.

36 SOIL-BORNEDISEASES

81

Orobanche spp. in greenhouse

Table 24. Soil-borne fungal diseases

Disease

Damping off diseasesCause: Various fungi,such as: rhizoctonia solani,Pythium spp.Alternaria spp.

Description Season Control

Damage to young seedlingswhile in nursery or field.Seedlings turn black, shrivelat root-stem junction andwilt.

All year round Soil and seed sterilization;avoid humidity and excessmoisture in soil andsubstrates.

Fusarium wiltRaces 1 and 2 Fusariumoxysporum f.sp. lycopersici

Plants rot and dry up, xylemvessels turn brown. Theplants wilt completely.

Mainly during the hotseasons.In high soil infection thediseases will be all yearround

Resistant varieties; soilsterilization; rootstock-grafting.

Verticillium wiltVerticillium dahliae

Adult plants rot and dry out,xylem vessels turn brown.The plants wilt in the dayand recover at night butusually die.

All year round Resistant varieties; soilsterilization; rootstockgrafting.

germination of weeds

Cuscuta campestris climbing on foliage

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Disease

Southern blightSclerotium rolfsii

Description Season Control

Roots and stems at soil levelrot; plants wilt anddehydrate; white myceliumand light brown spots appearon the roots and stems atsoil level as well as on fruitlying on the ground.

Summer, combination ofhigh temperatures and highhumidity conditions.

Soil sterilization; solarsterilization; prevention ofexcess moisture in soil.

White moldSclerotinia sclerotiorum

Root, stem and fruit rot.Dried hollow stem with blackbodies known as sclerotia.

Winter and spring. Highhumidity conditions andmoderate temperatureencouraging the disesase.

Soil sterilization; ventilation;chemical fungicides soilmulching.

Corky rootPyrenochaetalycopersici

Plant degenerates, rootshave brown lesionsarranged in bands with2.0-5.0 cm lengthwisecracks.

Winter and spring.Spreads in heavy soils.

Crop rotation;soil sterilization;rootstock grafting.

Crown and root rotFusarium oxysporum f.sp.radicis-lycopersici

Adult plants can wilt, rootsystems dry with brown rotin cortex and xylem, stemcankers at soil level; 20-30cm of the stem above soillevel becomes grayish-pinkwith brown center.

Winter and spring.Spreads undersaline conditions.

Resistant varieties;sterilization of seeds, soil,and greenhouseatmosphere; rootstockgrafting.

Pythium damping off

Damping off – fullnessand lack of uniformity

Fusarium – Crown rot

Fusarium wilt of susceptible tomato variety

Fusarium – Crown rot

Infection withpythium

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While most of the fungi that attack tomato plants arepathogenic and microscopic, a few are macroscopic.Parasitic fungi develop mycelia, have insufficient chlorophylland therefore, invade host plants to obtain carbohydrates.More than one pathogen is often present in tomato plantsat any given time. This indicates the existence of conditionssuitable for their development and their ability to causefoliage, stem and fruit diseases. These fungi and thediseases that they cause can be controlled by eliminatingand avoiding the conditions that promote their development,such as humidity and high or low temperatures, or acombination of both.Pathogenic fungi reproduce in various ways that enablethem to spread far and thus reach hosts in different placesand cause diseases when the conditions are right.Due to its importance, data regarding late blight causedby the fungus Phytophthora infestans is presented in Table25. This disease is widespread in most tomato growingareas and affects tomatoes and potatoes. An epidemicoutbreak of the disease could cause very severe financiallosses. Late blight attacks leaves and stems, forminglarge 3-4 mm brown spots with a grayish-white halo(mycelia and spores). Dark brown spots form on the stemsand petioles (leafstalks) and as the disease develops inthe field, the vegetation seems to wither. Dry or firm brownrot develops on the infected tomato fruit.The fungus produces lemon-shaped sporangia which, inthe presence of adequate water at 15ºC for 4 - 6 hours,release zoospores. Mycelia develop in plant tissue intemperatures of 18-20ºC. This disease develops especiallyin humid conditions, in spring and autumn, when the nightsare cool and the days are warm. Sprinkler irrigation

Tomato plant infected with verticillium dahliae

Pyrenochaeta lycopersici - Corky root

Roots infested with nematodes

Sclerotium rolfsii (southern blight)

37 TOMATO LEAFDISEASES

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encourages the conditions for development of this diseasewhen temperature conditions are right. Hot dry weatherdelays and even suppresses development of the disease.Today the most widespread control methods are agro-technical, and involve preventing conditions for thedevelopment of the disease, such as avoiding wetting theplants, removing excess humidity, and greenhouseventilation.

Table 25. Fungal leaf diseases

Alongside this method, there are also chemical controlmethods through preventative or systemic chemicals.However, the repeated use of these substances results inthe development of resistant strains of the fungus.Consequently, a wise Integrated Pest Management (IPM)routine is one that combines agro-technical and chemicalmethods.

Disease

Late blight or tomato blightPhytophthora infestans

Description Season Control

Dark spots on leaves, stemsand fruit. In severe cases,the entire plant dries up.

Spring and winter andsometimes autumn

Prevent moisture on theplants; good ventilation andchemical control;soil mulching.

Early blightAlternaria solani

Circular spots, usuallyconcentric, on the leaves,stems and fruit, especiallyadult plants.

All year round Prevent moisture on theplants; good ventilation andchemical control; soilmulching.

Gray leaf spotStemphylium solani

Small round or elongated,brown-black spots onleaves and stems that oftendry out and crack.

All year round Resistant varieties;chemical control; preventunnecessary humidity; soilmulching.

Powdery mildewLeveillula taurica

Yellowish spots on leaves,white spores usually on theunderside of leaves andsometimes on the upperside.

All year round - on adultplants the diseasedevelops quickly in warmand dry environments

Chemical controlimmediately withappearance of symptoms;tolerant varieties.

Gray moldBotrytis cinerea

Gray rot on leaves, stem andfruit accompanied by grayspores. Ghost spots on fruit.

Autumn, winter andspring, high humidity-encouraging infection withBotrytis

Prevent moisture on theplants; good ventilation,chemical control andsanitation; soil mulching

White moldSclerotiniasclerotiorum

Rot at the base of stems,stems, fruits and leaves.Hollow stem with blacksclerotia in the pith.

Winter and springhigh humidity

Soil sterilization; ventilation;chemical control; soilmulching.

Leaf moldFulvia FulvaCladosporium Fulvum

Yellow spots on leaves,greenish-gray spores on theunderside of leaves.

Summer, autumn andwinter. High humidity, thedisease develops quicklyat 20º-27ºC.

Prevention of humidity;resistant varieties; chemicalcontrol and soil mulching.

Powdery mildewOidium lycopersici

Irregular white spots on theupper side of the leaves,strong infected leavesusually become yellowishand non-effective.

All year round Chemical controlimmediately withappearance of symptoms.

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Botrytis – Ghost spots

Botrytis – Stem rot

Fruit rot

Early blight (Alternaria solani) on seedlings

Early blight on fruit

Botrytis Early blight on leaves

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Powdery mildew - Oidium lycopeici

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Powdery mildew - Leveillula taurica

White mold dried stem with sclerotia

White mold on stems

Leaf mold - Fulvia fulva

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Infection on foliage and fruit

Fruit infection

Infection of tomato plants and fruit with Phytophthora infestans (late blight)

Foliage infection

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In the group of plant diseases that are caused by bacteria, thevarious types of diseases are distinguished according to theaffected area and the appearance of damaged tissue.Accordingly, the best-known types are:1. Parenchymatous diseases that cause rot or necrosis

of the parenchyma tissue; the final result is wilting ofthe plants.

2. Diseases that develop local necrosis, in which casethe damage is local. The developing spots have roundor ribbed shapes.

3. Diseases causing various parts of the plants to die off.Bands encircling parts of the plant that cause thebranches or young shoots to die off.

4. Diseases of the xylem vessels. Diseases that developin the xylem vessels of plants and damage the xylem,resulting in the plant wilting and dying.

Note:Soil treatment with Formalin is effective in controllingbacterial plant pathogens occurring in Israel, such asClavibacter michiganensis, streptomycess spp. and others.

38 BACTERIALDISEASES

Bacterial speck on foliage

Table 26. Bacterial diseases in tomatoes

Disease

Bacterial speckPseudomonas syringaetomato

Description Control

Bacterial spotXanthomonas campestrisvesicatoria

Tomato pith necrosisPseudomonas corrugata

Bacterial soft rotErwinia cartovora

Southern bacterial wiltPseudomonas solanacearum

Bacterial cankerClavibacter; corynebacteriummichiganensis

Brown angular spots with a clearly defined yellow halo onleaves. Brown dark spots of 3-4 mm on stems, fruits witha dark green halo around them. Spreads in wet weather,wounds plants by drops of water from covers and gutterswhich encourages infection.

Lower leaves drop off followed by wilting of the entire plant,no yellowing occurs with this disease. When the stem iscut a slimy gray material oozes out. The disease spreadsunder high humidity - tropical and subtropical conditions.

Soft rot on stems, yellowing of foliage. Part of the stembecomes brown causing wilting of the plants. In dryconditions diseased plants overcome the infection andgrow again.

Hollowing of the pith, stems rupture. Plants wither and wilt.Small cankerous and white spots on fruits, stems, leavesand brown in the center resembling a bird’s eye.

Leaflets turn yellow and plants wilt completely. Brown areaon the stems and the pith look glossy and darker near thevessels. Appearance of adventitious roots causing splitson stem. High humidity and high levels of nitrogen andvegetative growth encourage the bacteria.

Irregular brown spots on leaves and along the stemsometimes the center of the spots dry and fall out. Fruitinfection began as small black spots which later becomebrown and scabby spots surrounded with an oily halo.

Seed treatments, crop rotation,avoidance of moisture on theplants and use of coppermaterials in case of infection;use tolerant varieties to bacteria.

Use disease-free seeds;avoid high humidity in thegreenhouses; good sanitationand control by copper materials.

Soil drying and sterilization,removal of diseased plants fromgreenhouses. Good sanitaryconditions by pruning andcorrect handling of the plants.

Soil and seed sterilization, usecrop rotation and goodsanitation by plant pruningand management.

Good sanitation, avoid highhumidity; Good sanitation.Use crop rotation; soil dryingand sterilization.

Since the bacteria survive insoil, needs crop rotation; soilsterilization and use ofrootstocks for grafting.

Bacterial speckBacterial spot

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Bacterial canker

Viral diseases differ from other parasitic diseases. Otherparasitic disease pathogens can be identified with an opticmicroscope, while viral disease pathogens can only bedistinguished with an electronic microscope. Viralpathogens have various shapes - ball, string or stick - andthey are measured in nanometers (millionth of a millimeter).The chemical composition of plant viruses is relativelysimple and those that have been examined are composedof protein and nucleic acids. Viral diseases can be identifiedaccording to their important vector and symptoms.

39 VIRALDISEASES

Viruses can be divided into two main groups:1. Non-persistently transmitted viruses: The virus is

acquired by a vector in a short acquisition period froman infected plant and is immediately transmitted to ahealthy plant. However, the vector looses its infectingability after short period of time.

2. Persistent transmitted viruses: A vector acquiresthe virus in a long acquisition period for a relativelylong period. The virus can only infect a healthy plantafter an incubation period in the insect’s body.A relatively long period on a healthy plant is requiredfor the virus to be transmitted. In this case, the virusis usually persistent in the vector that continues totransmit the virus during its lifecycle.Due to the significance of the tomato yellow leaf curlvirus (TYLCV) in tomato production, a review describingthe main characteristics of this virus follows:

Tomato yellow leaf curl virus (TYLCV)TYLCV geminivirus causes severe damage to tomatocrops in Israel and other countries. The disease causesnormal growth to stop, new leaves are small and curledin groups at the top of the plant and they often becomeyellow. The damage is most substantial when youngplants become infected and there is generally no fruit set.This virus is universally widespread and can today befound in the Mediterranean region, Africa, Asia, EasternEurope including the CIS, Latin-American countries, theCaribbean Islands, Australia and it has recently also beenfound in Florida in the USA. Its wide distribution is mainlycaused by transport of infected plant material or infectedwhitefly vectors.The virus is transmitted exclusively by the tobacco whitefly(Bemisia tabaci). It is not transmitted mechanically; howeverit can be transmitted through grafting. The virus is nottransmitted through seeds or by physical contact betweenplants or by cross-pollination.Stranglewort (Cynanchum acutum), little mallow (Malvaparviflora), jimsonweed (Datura stramonium) sow-thistle(Sonchus oleraceus) and certain tobacco varieties areamong the alternate virus hosts identified so far.

Pseudomonas corrugata

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Bacterial canker

Viral diseases differ from other parasitic diseases. Otherparasitic disease pathogens can be identified with an opticmicroscope, while viral disease pathogens can only bedistinguished with an electronic microscope. Viralpathogens have various shapes - ball, string or stick - andthey are measured in nanometers (millionth of a millimeter).The chemical composition of plant viruses is relativelysimple and those that have been examined are composedof protein and nucleic acids. Viral diseases can be identifiedaccording to their important vector and symptoms.

39 VIRALDISEASES

Viruses can be divided into two main groups:1. Non-persistently transmitted viruses: The virus is

acquired by a vector in a short acquisition period froman infected plant and is immediately transmitted to ahealthy plant. However, the vector looses its infectingability after short period of time.

2. Persistent transmitted viruses: A vector acquiresthe virus in a long acquisition period for a relativelylong period. The virus can only infect a healthy plantafter an incubation period in the insect’s body.A relatively long period on a healthy plant is requiredfor the virus to be transmitted. In this case, the virusis usually persistent in the vector that continues totransmit the virus during its lifecycle.Due to the significance of the tomato yellow leaf curlvirus (TYLCV) in tomato production, a review describingthe main characteristics of this virus follows:

Tomato yellow leaf curl virus (TYLCV)TYLCV geminivirus causes severe damage to tomatocrops in Israel and other countries. The disease causesnormal growth to stop, new leaves are small and curledin groups at the top of the plant and they often becomeyellow. The damage is most substantial when youngplants become infected and there is generally no fruit set.

This virus is universally widespread and can today befound in the Mediterranean region, Africa, Asia, EasternEurope including the CIS, Latin-American countries, theCaribbean Islands, Australia and it has recently also beenfound in Florida in the USA. Its wide distribution is mainlycaused by transport of infected plant material or infectedwhitefly vectors.The virus is transmitted exclusively by the tobacco whitefly(Bemisia tabaci). It is not transmitted mechanically; howeverit can be transmitted through grafting. The virus is nottransmitted through seeds or by physical contact betweenplants or by cross-pollination.Stranglewort (Cynanchum acutum), little mallow (Malvaparviflora), jimsonweed (Datura stramonium) sow-thistle(Sonchus oleraceus) and certain tobacco varieties areamong the alternate virus hosts identified so far.

Pseudomonas corrugata

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Most commercial tomato varieties are susceptible to thevirus. Bean plants are also susceptible to this virus. Incut flower production in Israel, TYLCV has also seriouslyaffected Lisianthus spp.The pathogen has been identified as having Gemini-shapedmolecules characteristic of the geminivirus family, and areapproximately 18x30mm in size. They envelope a singlemolecule of single strain DNA composed of 2787nucleotides. For transmitting the virus naturally, the whiteflyrequires at least a few minutes to acquire the virus fromphloem tissue of an infected plant. The longer theacquisition period, the higher the concentrate of acquiredparticles. A latent period follows, when the whitefly is notable to transmit the acquired virus. This latent period lastsabout eight hours during which time the virus passes fromthe whitefly’s mouthparts into its digestive system. Thevirus passes from the digestive system to the hemolymph,and then enters the salivary glands at the front of theinsect’s head. Once the whitefly has acquired the virus,it is able to infect plants throughout its lifecycle. A singlewhitefly is able to infect diverse types of plants. Thenumber of infected plants increases with the number ofwhitefly vectors.The symptoms of the disease are typical. However toexamine the virus in the plants and in the whitefly, newmolecular methods have been developed for identificationand verification of various isolates, by using detectorsbased on viral nucleic acids.Agrotechnical methods, including insect-proof nets and

insecticide control, are used to reduce the damage causedby the disease. The most efficient method is the cultivationof resistant or tolerant varieties, some of which are availableon the market.

Other damaging viruses:

Tomato bushy stunt virus (TBSV)TBSV causes stunted growth and leaf chlorosis andnecrosis. In severe cases, there is abscission of flowersand small fruit. In developing and mature fruit there canbe browning under the calyx and at the bottom of the fruit.The virus, which was first identified in California, is foundin the soil, disseminated through water and is mechanicallytransmitted even by pruning suckers or side-shoots. Nospecific vector is known.

Tomato chlorosis virus (ToCV)This is a new disease. Plants infected with ToCV developchlorosis in the lower leaves, which spreads to the upperparts of the plant. Damaged plants are less vigorous andproduce a low yield. Fruit is small and ripening is delayed. At the end of the 1990s, the disease spread significantlyin the Malaga Province in Spain, and caused severedamage to tomato fields. There was widespread infestationof tobacco whitefly in the tomato fields, which transmittedthe disease to healthy plants. Tests showed that Bemisiatabaci biotype “Q” was the most common whitefly.

Disease

TYLCVTomato yellowleaf curl virus

Damage Control

TMVTobacco mosaicvirus

PVYPotato virus Y

Table 27. Viral diseases in tomatoes

CMVCucumbermosaic virus

TSWVTomato spottedwilt virus

Infected plants become yellow; leaves become smalland curled, growth stops and no fruit set. Period ofinfection according to the activity of the whitefly.

Chemical control of the whitefly thattransmits the virus. Use of insect proofnets and cover with UV filtering plasticand use of resistant varieties to the virus.

Round spots on leaves and some necrosis, witheringof plant branches, malformation and discoloration offruits, usually green, yellow and red raised rings onthe fruit skin.

The virus is transmited by aphids causing mosaic spotson leaves which become narrow and curled, especiallyat the top of the plants. Infected plants produceunmarketable fruits.

Brown elongated spots on leaves and fruits. Plantsbecome bushy, yellowish and leaves curl; viruscauses discoloration of fruits.

Mosaic spots on the leaves and the fruits. An infectedplant is generally stunted and causes necrosis on fruits,leaves and stems.

Monitoring and reduction of the westernflower thrips population which transmitsthe virus, good sanitation, use insect proofnets; chemical control of the thrips anduse of resistant varieties.

Use insect proof nets, good sanitation,avoid growth of weeds and other hostsof the virus close to tomato fields. Goodsanitation surrounding thegreenhouses.

Use insect proof nets, protectedconditions, sanitation, chemical controlof aphids and avoid growth of weedswhich can be a host for the virus.

Use of resistant varieties; use seeds thatare treated for the virus. Use crop rotationin soils infected by TMV. Steam andsterilize equipments and containers anduse sanitation before handling the plants.

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Tobacco mosaic virus on leaves

Tomato yellow leaf curl virus

PVY on foliage

Tobacco mosaic virus on fruit

Pepino mosaic potexvirus (PepMV)PepMV was first reported and diagnosed in Peru in 1974,in Solanum muricatum. In 1995, the virus was reported intomato greenhouses in Holland and South America. Thevirus in Holland is different from that in Peru, which iswithout symptoms. In experiments with artificialcontamination, the virus infected other solanaceous crops,such as eggplant, pepper and potato.The symptoms of the virus that was discovered in Hollandare strongly expressed when temperatures are low, aswell as on cloudy days, and disappear in high temperaturesand clear days. Symptoms usually appear 2-3 weeksafter infection and the disease spreads along the row.Diseased plants appear stunted at the apex or displaysymptoms similar to those of hormone or herbicide damage.Leaves close to the apex display dark spots, while lowerleaves display brown spots. Dark brown spots often spreadto the stem and the inflorescence, which result in abscissionof the flowers. The browning can also appear on the calyxof mature fruit. Sometimes chlorosis appears on the leaves.

Pepino mosaic potexvirus is mechanically transmittedwhen pruning and treating plants, as it is found on hands,clothing, shoes and tools. British scientists found the virusin roots, and Dutch scientists found it after 90 days in dryvegetative matter. Seed transmission is unlikely. Controlis mainly by meticulous sanitation and protection throughoutthe growing period, starting with the treatment of seeds,production of healthy nursery plants, special care whengrafting and the use of protective means by workers, suchas frequent changing of work clothes, covering shoes anduse of disposable gloves. In the greenhouse, workerscontinuously inspect the crop to find infected plants,marking them and then carefully removing them. Directcontact with the infected plant is prevented by wearingprotective clothing and burning the diseased plants in aspecial place.

Tomato apical stunt (TASVd)Tomato plants infected with TASVd show stunted growthin the upper part of the plant as a result of shortenedinternodes close to the crown. The leaves in this area aredistorted, and mature leaves show crinkling and chlorosiswith brittle tissue. Sometimes necrotic spots also appearon the leaves. Vegetative growth is stunted and the fruitsize and color is also damaged.TASVd can be transmitted from diseased tomato plantsto healthy plants by grafting or mechanical inoculation,and this may be the reason for the pattern of spreadingalong the crop rows. The incubation period of the diseaseuntil the symptoms appear is about two weeks. In tomatoplants that were infected in experimental conditions, leavescurled downwards and the plants remained stunted andbushy.It is not clear how the disease reached Israel, and it isalso not known how it spreads in nature. Epidemiologicalresearch and identification of possible vectors may enableimplementation of steps to prevent the disease fromspreading to further tomato production areas.

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Tomato spotted wilt virus on fruit

PVY on fruit

Tomato spotted wilt virus on foliage

Tomato plant infected with TASVd

Tomato plants infected with PepMV© Queen’s printer for Ontario, 2001 reproduced with permission

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40 PESTS

The pests listed in the following table are the most commonin greenhouse tomato crops. Most of them also attackother crops. There are other pests, apart from those thatappear in the table, that attack many crops, such as molecrickets, cutworm (Agrotis), ants, birds, tobacco thrips,weevil, snails, mice and rats. Any of these can appear andcause damage to the plants during the early growingstages, and in the later stages can damage the plants aswell as the fruit.

Pest control is chemical, biological and agro-technical.In addition, biological control using predator insects (naturalenemies) against tomato pests is widespread.Pest management that includes the various chemical,biological and agro-technical pest control methods isknown as Integrated Pest Management (IPM). The use ofchemical pesticides is significantly reduced in an IPMregime, without any harm to the yields and quality of thetomatoes.

Heat necrosis in TMV-resistant tomatovarietiesExposure to heat of 28-30ºC or higher and to highconcentrations of TMV causes excess sensitivity in a certainpercentage of Tm-2a heterozygotic varieties, which isaccompanied by localized death of cells. This is known ashypersensitivity or heat necrosis. This reaction results innecrotic lesions on leaves and fruit. The lesions on thefruit are brown and not aesthetic. Damaged fruit is notmarketable. Certain genetic combinations, such as virus-resistant homozygotes, or the addition of other alleles,provide plants with virus resistance and prevent theoccurrence.

TMV hypersensitivity

Table 28. Pests

Pest

Tobacco whiteflyBemisia tabacirace B and Q

Description Damage Season

Flying insect 1-2 mmlong. Wings coveredwith a white powdery wax

Feeds on leaves andtransmits TLYCV virus

Spring, summer and autumnOften active in greenhousesall year round

AphidsVarious species, especiallyaphis gossypiimyzuspercisae

2-3 mm long, green toblack, wingless as wellas winged species

Feeds on leaves thatcurl as a result.Transmits PVY andCMV viruses.

All year round

Beet armywormSpodeptera exigua

Caterpillars are green whenyoung and turn gray orbrown, up to 3 cm in length.Hairs along the segments.

Feeds on leaves in longnarrow stips.

Spring and Autumn

BollwormHeliothis armigera

Green or reddish-brown todark brown caterpillar, 4 cmlong, with lighter stripesalong both sides and setaealong the back.

Feeds on fruit andleaves.

Spring, summer and autumn

LooperPlusia spp.

Caterpillar similar to theBollworm, light green withlight stripes along the sides,up to 3 cm long.

Feeds on leaves andsometimes on green andred fruit.

Summer, autumn and spring.

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Pest Description Damage Season

Small 0.3-0.4 mm red oryellow mite, yellow larvae,adult has 4 pairs of legs,found on the underside ofthe leaves.

Small gray moth up to 8-9mm long, larva colordepends on food it eats.Larva reaches 15 mmlength.

Tiny elongated mite whichcan only be seen throughmagnifying glass, onunderside of leaf on stemand fruit stalk.

Small yellow 2.4 mm fly,maggots colorless whenhatch, becoming orange-yellow, final size 3mm.

Adult is narrow and 1.2 mmlong. Yellow upper side,back appears dark and frontyellow when wings closed.pairs of legs, found on theunderside of the leaves.

Root Knot NematodeMeloidogyne spp.

Spider mitesTetranychus spp.

Potato tuberwormPhthorimaea operculella

Russet mitesAculops lycopersici

Leaf minersLiriomyza trifolii,Liriomyza huidobrensis

Microscopic, female usuallyround and male long andthreadlike.

Galls form in roots; wheninfection is heavy, plantswither and die.

Scratches the leaf cuticleand then feeds onleaves, usually on theunderside, creatingsilvery-gray spots,leaves dry up.

Larvae develop onleaves, worms thenmove to fruit, enteringunder the sepal andburrowing under stalkinto fruit.

Leaves and stalksgreen/dark-brown, ust-like, leaves dry up.

Maggots burrow tunnelsin leaves, reducingphotosynthetic area,secondary leaf diseaseinfection such as earlyblight and grey mold(Botrytis cinerea)

Found in flowers andplant tops. Could causemalformed fruit andtransmit TSWV virus.

All year round(for more details - page 34).

All year round - intensified indry weather.

Spring, summer and autumn

Spring and summer,intensifies in dry weather

All year round

Western flower thripsFrankliniella occidentalis

Young caterpillar is greenand turns dark gray orbrown-black. The bodysegment closest to the headhas two dark spots, theadult also has these spotsat the back.

Egyptian leaf wormSpodoptera littoralis

Feeds on all parts of theplant.

Summer and autumn

Black cutworms, adultcaterpillers are large brownor gray, mature larvae about4 cm long. Cutworms spendwinter as larvae in the soil,there are severalgenerations each year.

Cut crowns of youngplants, active at nightand hide during the dayunderneath plants belowthe soil surface.

Spring and autumn.Intensifies in soils rich infresh organic matirial.

CutwormsAgrotis Spp.

All year round

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Red spider mite damage on leaves

Russet mites damage on fruit

Russet mite damage on foliage and fruit

Red spider mite damage on fruit

Yellow spider mitesRed spider mites

Looper - plusiaCotton worm

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Bemisia tabaci - tobacco witefly

Leaf miner - Adult Pupa of leaf miner

Adult and caterpiller of potato tuberworm

Infection by potato tuberworm

Leaf miner injury

Western flower thrips

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BibliographyBIBLIOGRAPHY1. Banuelos, G. S., Offermann, G. P., and Seim, E .C. 1985.

High relative humidity promotes blossom-end rot on growingtomato fruit . HortScience 20 (5), pp. 894-895.

2. Benton Jones Jr., J. 1998. Tomato Plant Culture: In the Field,Greenhouse, and Home Garden.

3. Burnham, T. J. 1997. Storage for tomatoes. The Grower, pp.33-34 (March).

4. Den Outer R.W. and Van Veenendaal W.L.H. 1998. GoldSpeckles and Crystals in Tomato Fruits. Department of PlantCytology and Morphology, Agriculture University Wageningen,The Netherlands

5. Kretchman, Dale. 1990. Tomato disorders are preventable.American Vegetable Grower.

6. Navas-Castillo J., Camero, R., Bueno M. and Moriones E.2000. Severe yellowing outbreaks in tomato in Spain associatedwith infection of chlorosis virus. Experimental Station, Malaga,Spain, Plant Disease, Vol. 84, No. 8, pp 835-837.

7. Ohta Katsumi. 1993. Influence of the nutrient solutionconcentrations on cracking of cherry tomato fruit grownhydroponically. Japan Soc. HortScience 62 (2); pp 407-412.

8. Peet M. M., Gipson J .L., Whipker B. E. and Blankenship S.2000. Ethylene damage, what it is and how to prevent it, TheTomato Magazine, pp 16-20 (April).

9. Rylski, I., Shan, S. 1988. Effect of plant growth regulators ontomato fruit set and fruit growth under high temperatureconditions, First Annual Report, Agriculture ResearchOrganization, Volcani Center.

10. Sonneveld C. 1987. Magnesium deficiency in rock wool growntomatoes as affected by climate conditions and plant nutrition.Journal of Plant Nutri t ion (9-16), pp 1591-1604.

11. Stevens and Rick. 1986. Genetics and breeding in Athertonand Rudich. The Tomato Crop.

12. Winsor, G. and Adams, P. 1987. Diagnosis of minimal disordersin plants. Volume 3, Glasshouse Crops. London: Her Majesty’sStationary Office.

13. Wisler, G. 2000. A new disease is spreading. GreenhouseInsider

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List of Hebrew SourcesLIST OF HEBREW SOURCESƱ˙‡ϘÁ·†ÌȘ¯Ù†≠†˙Èχ¯˘È‰†˙È‚¯Â‡‰†˙‡ϘÁ·†ÌȘÂÁ†ÌÈÁ˜ÈÙ†¨ÌȘ˙†®≤∞∞¥©†Æ‡†¯Ï„‡

Ʊ≤≠±¥†ÌÈ„ÂÓÚ†˙„ÂÒȆү˜φ˙¯·ÂÁ†˙È‚¯Â‡‰

Æ≤Ï˘†Ë¯Ëȇ‰†¯˙‡†≠†‰ÁÈÓˆ†È˙··†˙È‚¯Â‡†˙ÂÈ·‚چτȂφ˙ˆÏÓ‰†®≤∞∞¥©†Æ‡†¯Ï„‡ÆÈ‚¯Â‡‰†Ô‚¯‡‰

Æ≥±∑µ†≠†Â†±¥¥†ÌÈʉӆ‰ÓÓÁ†˙ÂÈ·‚Ú†˙·Â‚˙†®±ππ≤©†ªÆÚ†ÛÒ‡†¨Æ‡†ıȷ˜·Ï†¨Æ‡†Ô˙Ó†¨Æ·†ÛÒÂȆ¯·Æ¯Â˘·‰†¯Âʇ·†ÔÂ˘È„Â†‰È˜˘‰Ï

Æ¥Æ¯Â˘·‰† ¯Âʇ·† ‰ÓÓÁ† ˙ÂÈ·‚Ú† ˙Ș˘‰Â† ÔÂ˘È„† ®±π∏∞©† ªÆ‡† ‰Èχ† ¨Æ·† ·È‚˘† ¨Æ·† ÛÒÂȆ ¯·

Ƶ‰„˘†ÈÈÂÒȆÌȯ˜ÁÓ†ÌÂÎÒ†≠‰ÁÈÓˆ†˙È··†˙ÂÈ·‚Ú·†ÌÈÓ†¯ÂÊÁÈÓ†®≤∞∞≤©†ªÂȯ·ÂÁ†Ʒ†ÛÒÂȆ¯·Æ±≤±≠±≥∂†ÌÈ„ÂÓÚ†≤∞∞±Ø≤†Ï·ӆ˙ÂÈ·‚Ú·

Æ∂‰˜ÏÁÓ‰†˙‡ˆÂ‰†ÆÔ˙¯·„‰Â†Ô˙ÂÁ˙Ù˙‰†¨ÌÈÙ¢‰†˜¯È‰Â†È¯Ù‰†˙ÂÏÁÓ†®±ππ∑©†ª†Æ¯†ÔÏ‚≠ȇ˜¯·ÆȇϘÁ‰†¯˜ÁÓ‰†Ï‰Ó†¨ÌÈÈÚ„Ó†ÌÈÓÂÒ¯ÙÏ

Æ∑Æχ¯˘È·†˙˜ÏÚ†®≤∞∞≥©†ª†Æ˘†„ÏÙÈϘ†¨È†¯Ò„Ï‚

Æ∏‰Î¯„‰‰†˙Â¯È˘†˙‡ˆÂ‰†¨‡ÂˆÈφÈÓ˜Ӊ†˜Â˘Ï†Ï·ӆ˙ÂÈ·‚چτȂ†®±π∏µ©†ª†ÆÁ†‚¯·ÊȂƯÙΉ†ÁÂ˙ÈÙ†˙‡ϘÁ‰†„¯˘Ó†¨Úˆ˜Ó‰Â

ÆπÏ˘†˙·Ï¢ӆ‰¯·„‰†®±ππ𩆪Æچχ„ӆ¨Æ‡†Â˜Â‡†¨ÆȆÔ˘†¨Æ†‚¯·ÏÈʆ¨Æ‡†ÔÈÈË˘È¯‚†¨Æ‡†Ï‡ÈÏÓ‚±ππ∏Øππ†¯˜ÁÓ‰†˙ÂÚ†ÌÂÎÈ҆Ɖ·¯Ú·†˙˜¯È†ÈÏ„Ȃ·†„ÈÓ¯·†ÏÈ˙Óφ˙ÂÙÂÏÁ≠Ú˜¯˜†ÈÚ‚Ù

Ʊ∞≠≤±†ÌÈ„ÂÓÚ†˙ÈÂو†‰ÂÎÈ˙†‰·¯Ú†Ù¢ÂÓ

Ʊ∞ÌÈÚ‚Ù†˙¯·„‰Ï†¯ÂËȘ·†Ú˜¯˜†ÈÂËÈÁ†Ì¢ÈȆ®≤∞∞≤©ª†ÆȆ‰˜ÈÒÓ†¨ÆÓ†ÔÓ¯‚ȯˆ¨Æ‡†Ô˙Ó†¨Æ‡†Ï‡ÈÏӂƱ∑±≠±∏∞† ÌÈ„ÂÓÚ† ≤∞∞±Ø≤† ̯„† Ù¢ÂÓ† ‰ÂÚ† ÌÂÎÒ† ¨®≤∞∞∞©† ‰ÓÓÁ·† ˙ÂÈ·‚Ú·

Ʊ±Ìȯ˜ÁÓ†ÌÂÎÒ†≤∞∞∞ر†˘ÈÎφ˙ÂÈ·‚Ú·†˙·ί‰†ÔÁ·Ó†®≤∞∞±©†ªÆÚ†Ô‡„Èʆ¨Æ˘†Ô˙„†¨Æ˘†ı‚Æπµ≠±∞¥†ÌÈ„ÂÓÚ†≤∞∞∞ر†˙˘Ï†˙ÂÈ·‚Ú·†‰„˘†ÈÈÂÒÈÂ

Ʊ≤ÌÂÎÒ†¨˙ÂÈ·‚Ú·†„ÈÓ¯·†ÏÈ˙Óφ˙ÂÙÂÏÁ†˙ÈÁ·†®≤∞∞≤©†ªÆ˘†Ô˙„†¨ÆÚ†Ô‡„Èʆ¨ÆȆҘʆ¨Æ˘†ı‚Æππ≠±∞≥†ÌÈ„ÂÓÚ†≤∞∞±Ø≤†Ï·ӆ˙ÂÈ·‚Ú·†‰„˘†ÈÈÂÒȆÌȯ˜ÁÓ

Ʊ≥ÆÏ·ӆ˙ÂÈ·‚Ú·†„ÈÓ¯·†ÏÈ˙Óφ˙ÂÙÂÏÁ†˙ÈÁ·†®≤∞∞≥©ªÆȆÔÂÏÁΆ¨ÆÚ†Ô‡„Èʆ¨ÆȆҘʆ¨Æ˘†ı‚Ʊ±±≠±±∏† ÌÈ„ÂÓÚ† ≤∞∞≤Ø≥† Ï·ӆ ˙ÂÈ·‚Ú·† ‰„˘† È È ÂÒÈ Â † Ìȯ˜ÁÓ† ÌÂÎÒ

Ʊ¥ÆÚ„Ó·†ÌÈÓÂÒ¯ÙφÔӈȆ„ÒÂÓ†˙‡ˆÂ‰·†Ï‡¯˘È·†ÌÈÁÓˆ·†ÌȘ„ÈÈÁ†˙ÂÏÁÓ†®±π∏µ©†ªÆˆ†È˜ÏÂÂÆπ±∞∞∑†ÌÈÏ˘Â¯È†∏∞±†Æ„Æ˙

ƱµÆßȆ˙¯·ÂÁ† ¨·¢Ú†Í¯Î† ¨‰„˘‰† ¨˜˙ÂÓ†ÚˆÓ·†˙ÂÈ·‚چτȂ† ®±ππ≤©† ªÆ‡† Ô„È·‡† ¨ÆÚ† Ô‡„ÈÊ

Ʊ∂Æ˙˜¯Èφۂ‡‰†¨Úˆ˜Ó‰Â†‰Î¯„‰‰†˙Â¯È˘†¨‰ÁÈÓˆ†È˙··†˙ÂÈ·‚چτȂ†®±ππ≥©†ªÆÚ†Ô‡„ÈÊ

Ʊ∑„¯˘Ó†¨Úˆ˜Ó‰Â†‰Î¯„‰‰†˙Â¯È˘†¨±π∏πØπ†˙˘Ï†‰„˘†ÈÂÒÈ·†¯˜ÁÓ†ÌÂÎÈÒ†®±ππ𩆪ÆÚ†Ô‡„ÈÊƯÙΉ†ÁÂ˙ÈÙ†˙‡ϘÁ‰

Ʊ∏ËÒ‚‡†Ó¢‰˘†˙‡ˆÂ‰·†˙ˆÏÓ‰†ÔÂÙ„†–†‰ÁÈÓˆ†È˙··†Ï·ӆ˙ÂÈ·‚Ú†Èʆ®≤∞∞≥©†ªÆÚ†Ô‡„ÈÊÆ≤∞∞≥

Ʊπ˙‡ϘÁ‰†„¯˘Ó†¨Úˆ˜Ó‰Â†‰Î¯„‰‰†˙Â¯È˘†¨˙˜¯È·†ÌÈÚ‚Ù†˙¯·„‰Ï†˙ˆÏÓ‰†®≤∞∞≤©†ªÆȆҘÊƯÙΉ†ÁÂ˙ÈÙÂ

Æ≤∞¨±ππ∞†·Èˆ˜˙‰†˙˘Ï†ÌÎÒÓ†Á„†¨ÌȘ˙ÂÓ†ÌÈÚˆÓ·†˙˜¯È†Ï„Ȃ†˙ÈÁ·†®±π𱩪†ÆȆ¯·Ú†¨ÆȆÔÁƉ·¯Ú†Ù¢ÂÓ†˙˜¯È‰†ÛÚ†˙ω‰Ï†˘‚ÂÓ

Page 109: O. zaidan tomato production

99

Æ≤±ÌÈ˘„Á†ÌȯˆÂÓ†˙ÈÁ·†®≤∞∞≥©†ªÆ˘†ÈÏȇ†¨Æ‚†Û˘¯†¨ÆÚ†Ô‡„Èʆ¨Æ¯†„È·¯†¨Æ‡†˙ÙȆ¨Æ˘†„„†¨ÆÁ†Ï‡˜ÊÁÈÆ≤≥≠≥∏† ÌÈ„ÂÓÚ† ≤∞∞≤Ø≥† Ï·ӆ ˙ÂÈ·‚Ú·† ‰„˘† ÈÈÂÒȆ Ìȯ˜ÁÓ† ÌÂÎÒ† ¨˙ÂÈ·‚Ú·

Æ≤≤‰˜ÏÁÓ‰†˙‡ˆÂ‰†¨Ï‡¯˘È·†ÌÈÁÓˆ†˙ÂÏÁÓ†®±ππ∏©† ª˙ÙȆԷ†˙ÙȆ ÈËÏÙ†ÛÒÂȆ ¨Ì˙¯†ÛÒÂÈÆÔ‚„†˙È·†¨È˜Ï†Êίӆ¨ÌÈÈÚ„Ó†ÌÈÓÂÒ¯ÙÏ

Æ≤≥˜˙ÂÓ†ÚˆÓφ‰¯˜·Â†ÔÂ˘È„†¨‰È˜˘‰†˙ίÚÓ†˙È˙˘˙†˙Ήφ˙ÂÈÁ‰†®±ππ∏©†ª‰È¯‡†˜ÁˆÈƉ„˘†˙Â¯È˘†Û‚‡†¨Úˆ˜Ó‰Â†‰Î¯„‰‰†˙Â¯È˘†¨‰ÁÈÓˆ†È˙··

Æ≤¥ÌÈÓÂÒ¯Ùφ‰˜ÏÁÓ‰†˙‡ˆÂ‰†¨Ì¢ÈȆ˙¯˜Ú†¨ÌÈÁÓˆ†Ï˘†‰È‚ÂϯȆ®±ππ≥©ª†„‚†ÔÈÈˢ·ÂÏÆÔ‚„†˙È·†¨È˜Ï†Êίӆ¨È‡Ï˜Á‰†¯˜ÁÓ‰†Ï‰Ó†¨ÌÈÈÚ„Ó

Æ≤µ˙ÂÈ·‚Ú†ÔÂÒÁ‡·†Ìȯ˜ÁÓ†¨˙ȇϘÁ†˙¯ˆÂ˙†¯˜Áφ‰˜ÏÁÓ‰†Á¢Â„†®≤∞∞≥©†ªÂȯ·ÂÁ†Ƈ†¯ËÎÈÏƱ∏≥≠±π∂† ÌÈ„ÂÓÚ† ≤∞∞≤Ø≥† Ï·ӆ ˙ÂÈ·‚Ú·† ‰„˘† ÈÈÂÒȆ Ìȯ˜ÁÓ† ÌÂÎÒ† Æ≤∞∞≤Ø≥

Æ≤∂Æȯˆ ‡ÂˆÈÈφ ˙„ÚÂÈÓ‰† ˙ÂÈ·‚Ú† ÔÂÒÁ‡·† Ìȯ˜ÁÓ† ®±ππ∏©† ªÂȯ·ÂÁ† ̯ÂȆ Ò˜ÂÙ

Æ≤∑Æχ¯˘È·† ÛÈ˘φ ÌÈ„¯Â† ÈÏ„Ȃφ ÈÚˆ˜Ó† Íȯ„Ó† –† „¯Â‰† ͯ„† ®±ππ𩆠ªÌÈÒȆ ÒÈÙ

Æ≤∏‰È˜˘‰†˜˘ÓÓ†˙ÂÚˆÓ‡·†‰ÓÓÁ†ß‚Ú†˙ÂÎȇ†ÏÂ·È†Ï˘†‰ÙÂÏÁ˙†®±ππ∂©†ªÂȯ·ÂÁ†ƈ†Ë‡ÏÙÆÌÈÁÈÏÓ†ÌȯÈÙ˘†ÌÈÓ·

Æ≤π˙ÈÏÓ˘Á†‰¯Â·„Ó†‰ÏÈÚȆ¯·†˙¯Â·„†®±ππ≤©†ªÆ‡†‰˜ÒÏȯ†Æ¯†„˜˘†¨Æ˜†„ÏÙʯ†¨Æ‡†ÔÓÒ¯ÙÆ·†˙¯·ÂÁ†¨‚¢Ú†Í¯Î†¨‰„˘‰†¨‰ÓÓÁ†ß‚چȯن˙˜·‡‰·

Æ≥∞‰„˘†ÈÈÂÒȆÌȯ˜ÁÓ†ÌÂÎÒ†¨˙ÂÏÂ΢‡·†˙ÂÈ·‚Ú†ÛÚ†ÁÂ˙ÈÙ†®≤∞∞±©† ªÂȯ·ÂÁ† Ƈ†ÔÓÒ¯ÙÆ∏±≠∏∏†ÌÈ„ÂÓÚ†≤∞∞∞ر†˙˘Ï†˙ÂÈ·‚Ú·

Æ≥±‰ÙÈˢ†˙¯ÊÚ·†ÛÈ˘‰†¯Á‡Ï†˙Âȯˆ˙ÂÈ·‚Ú†˙ÂÎȇ†¯ÂÓÈ˘†®≤∞∞≤©†ªÆ˘†ÈÚϘχ†¨Æ‡†˜ÈÏÙÆ¥±≠¥≥† ÌÈ„ÂÓÚ† ≤∞∞≤† ËÒ‚‡† ¨˜˘Ó† ‰„˘† Ô‚† ƉÒÁ‡‰† ÈÙφ ‰ÓÁ† ‰˘¯·‰Â

Æ≥≤Æ≤±≤≠≤∂∞† ÌÈ„ÂÓÚ† ߇† ˙˜¯È† ¨˙‡ϘÁφ ‰È„ÙÂϘˆÈ‡‰† ®±π∏𩆠ª† ÆÁ† ‚¯·ÊÈ‚† ¨Æ† ¯„Ș

Æ≥≥Æ˙ÂÈ·‚Ú† ÏÚ† ϯ˙‡† ˙ÚÙ˘‰·† Ìȯ˜ÁÓ† ®±π∑±©ª† Ɔ ¯„Ș† ¨Æ·† ˜È„¯† ¨Æ‡† ¯ËϘ

Æ≥¥‰È·‚Ú‰†È¯Ù†Ï˘†‰ÏÈ„‚‰Â†‰ËÁ‰†˙¯·‚‰†®±π∏∞©ª†ÆÁ†Ì‰¯·‡†¨Æ„†¯È‰†¨Æ˘†¯ÂÓ†Ô‚†¨Æ‡†‰˜ÒÏȯ¨„ÁÂÈÓ†ÌÂÒ¯Ù†¨È‡Ï˜Á‰†¯˜ÁÓ‰†Ï‰ÈÓ†¨‰ÁÈÓˆ†È¯ÓÂÁ·†ÒÂÒȯ†˙ÂÁ¯Ù˙†¯ÂÚȆ˙¯ÊÚ·

Ʊ∑∏†¯ÙÒÓ

Æ≥µ‰Î¯„‰‰†˙Â¯È˘†¨¯‰‰Â†‰ÏÙ˘‰†ÊÂÁÓ·†Ú˜¯˜·†Ï„Ȃ·†˙˜¯È†˙ÈȘ˘‰Â†ÔÂ˘È„†®≤∞∞∞©†ªÆ‚†Û˘¯Æ‰„˘†˙¯˘†Û‚‡†¨Úˆ˜Ó‰Â

Æ≥∂˙ÂÁ˙Ù˙‰‰†ÏÚ†‰Áȯى†ÏÚ†‰È¯˜‰†˙ÓˆÂÚ†˙ÚÙ˘‰†®±π∑𩆪ÆÓ†Ò˜ÂÙ†¨Æ‡†‰˜ÒÏȯ†¨Æ‡†‡È‚˘Æ≤∞∏†¯ÙÒÓ†ÔÈËÏ·†¨ß‚Ú·†È¯Ù‰†Ï˘