LEAFMlNERS ON GREENHOUSE CHRYSANTHEMUM ...scentsoc.org/Volumes/JAE/v1/3/00013256.pdfChromatomyia syngenesiae control evaluations were conducted at the Glasshouse Crops Research Institute

LEAFMlNERS ON GREENHOUSE CHRYSANTHEMUM: CONTROL OF CHROMATOMYlA SYNGENESIAE' AND LIRIOMYZA TRIFOLII'·2

R. K. Lindquist 3 , M. L. Casey\ N. Helyer" and N. E. A. Scopes'

Ab.~lract: Cypcrmethrin, methomyl, pyrazophos. pirimiphos-methyl, and triazophos were evaluated for control of Chromatomyia syngenesiae (Hardy) and Liriomyza tri{o/ii (Burgess) on greenhouse chrysanthemum. Pyrazophos and triazophos gave good control of both C. .'>Yrlgenesiae and L. trifolii larvae, but the former species was more susceptible to other insecticides used. Pryrazophos and triazophos also killed emerged C. syngenesiae adults. In addition to the above materials, permcthrin, methoprene, and 8D52618 were evaluated using two spray volumes tis. L. trifolii larvae. Spraying plants with a hand sprayer at 3168 liter/ha generally resulted in better L. tn/alii control than when plants were sprayed in a spray chamber at 1320 liter/ha. Effects of most materials evaluated us. L. tri{o/ii were seen in the larval stuge, but mortality in methoprene treat.ments did not occur until pupation. Significant pupal mortality also occurred with cypermethrin, permethrin. and methomyl in one experiment.

Key Words: Chromalomyia syngenesiae, Liriomyza tri/olii. leafminers, chrysanthemum.

J. Agric. Entomol. 1(3), 256-263 (July 1984)

Chromatomyia (= PhyLomyza) syngenesiae (Hardy), the chrysanthemum leafminer, is a widespread pest in Europe and North America, and can cause severe injury to chrysanthemum (Spencer 1973). Liriomyza trifolii (Burgess) has been a serious pest of horticultural crops in Florida for over 30 years (Price 1983), and has recently become a problem outside of its native area, causing injury in Africa, Europe, and South America (van de Vrie and Dirkse 1982). Most past and current management efforts are based on insecticides, with both species sometimes difficult to control (Anon. 1980; Alverson and Gorsuch 1982; Gurney and Hussey 1974; Parrella el al. 1982: van de Vrie and Dirkse 1982).

Recent reports have indicated that L. tri{olii may be more resistant to pesticides than other common agromyzids, including L. sativae Blanchard and L. huidobrem;is (Blonchard) (Parrella el al. 1981). Price and Stanley (1983) speculated that use of certain pesticides could lead to L. tri{olii becoming the dominant leafminer species in an agroecosystem. Within L. trifolii populations, resistance to a particular pesticide is suspected to vary widely. Keil and Parrella (1983) reported a 35·fold difference in resistance to permethrin in two California L. trifo!ii populations.

Results of experiments are reported which compare control of C. syngenesiae and L. tri{oiii larvae on chrysanthemum. Also reported are data comparing different spray volumes for L. trifoiii control.

1 DlPTERA: ,\gromyzidne 2 SlIlnnes snd reselttc"h support provid"'d by SUtte lind Federlll funds IIpprOllr1l1ted to the Ohio Al(rieullutlll He~eltrch and

Deyelopment Center, The Ohio SUtte University. Journal Article No. 10[,·83. Recei"ed ror publiclltion 6 AUI:\lst 1983; "l;eepted 4 April 1984.

3 Proressor lind Technicinn II, respt'ctivcly, Ohio Agricultural Reselltch lind Devel"pment Center of The Ohio Stllte University, Wooster. OH 44691.

4 Technical Assistant and Senior Entomologist, respectively. Gla8shollse Crops Hesearch Institute. J.ittlehampton. Englund.

256

257 LINDQUIST et aL Leafminer Control on Chrysanthemum

MATERIALS AND METHODS

Chromatomyia syngenesiae control evaluations were conducted at the Glasshouse Crops Research Institute (GCRn, Littlehampton, England, and L. trifolii evaluations were conducted at the Ohio Agricultural Research and Development Center (OARDe), Wooster, OH. Insects of unknown pesticide resistance characteristics were used at both locations. Objectives were to evaluate different pesticides against eggs and different larval stages.

Chromatomyia syngenesiae Potted chrysanthemum plants (Chrysanthemum X morifolium cv. 'Snowdon')

were used. Plants were grown in 10 cm-Diam pots, watered as required with a solution including 200 ppm N, P, and K. For each leafminer age group, 30 plants ca. 41 em high, were exposed to C. syngenesiae adults for 48 h (10 plants in each of three cages, with each cage containing 50 C. syngenesiae adults). Treated stages were eggs, 2 - 4, 4 . 6, and 6 - 8 d·old larvae. The pesticides and rates included in experiments for C. syngenesiae control were: methomyl, 0.05% AI (Lannate® 25% WP), pirimiphos-methyl, 0.05% AI (Acetellic'" 25% EC), triazophos, 0.04% Al (Hostathion'" 40% EC), pyrazophos, 0.0225% AI (Afugan'" 30% EC, and cypennethrin 0.01% AI (Ripcord@ 10% EC). Sprays were applied on upper leaf surfaces to the point of run-off with a gas chromatography atomizer inside a spray chamber. After treatment, plants were kept in a plant growth room at 22°C. For efficacy us. eggs, the subsequent number of visible leafmines was recorded. Leaves were examined under a binocular microscope. Younger larvae were recorded as alive or dead, and older larvae as alive, dead, or pupated. Percent mortality was calculated for the larval stages, data were analyzed, and means separated by Duncan's new multiple range test. Leaves containing pupae were removed, arranged on the bottom of plexiglass cages and held for adult emergence. In contrast to L. trifolii, C. syngenesiae pupate within the leaf. Emerged adults were observed for any mortality caused by residual effects of pesticides.

Liriomyza tn/olii Methods of infesting plants with L. trifolii were as described above, except that

t.he exposure time to ovipositing adults was 24 hand cultivar 'Iceberg' was used. Plants were approx. 25 em high when treated. Treated stages were eggs, 4 - 5 d and 6 - 7 d-old larvae. Insecticides were applied with a compressed-air sprayer (300 gallA., 3168 liter/hal or in a spray chamber (125 gallA., 1320 liter/ha) (Research Instrument Mfg. Co., Guelph, Ontario). Sprays were applied to both upper and lower leaf surfaces with the compressed-air sprayer, and only to the upper surfaces with the spray chamber. Materials used and application rates (when different from those listed previously) were: triazophos, pyrazophos, cypermethrin (Ammo® 2.5 EC), permethrin, 0.025% AI (Ambush@ 2 EC), pirimiphos-methyl, 0.025% AI, methomyl 0.25% AI (not applied in spray chamber), methoprene 0.07, 0.26% AI (Minex'" 5 E), and SD 52618 85 WP 0.02, 0.04, 0.08 AI.

After treatment, plants were held in leafminer-free cages and the number of visible leafmines was recorded. When applications were made to plants containing older larvae, infested leaves were removed 24-h posttreatment and placed in paper envelopes (one envelope/plant) for pupal collection. When eggs and younger larvae were treated, plants were held in leafminer-free cages for 7 and 4 ct, respectively,

258 J. Agric. Entomol. Vol. 1, No.3 (1984)

until larvae were almost ready to pupate; leaves then were removed and placed in envelopes as described above. Removed leaves were held for ca, 7 d at 25,5°C and 80% RH. Pupae then were collected, placed in vials, and held for 14 d under these same conditions, when adult emergence was recorded.

For the egg stage, data were recorded as with C, syngenesiae. Percent mortality was calculated in two ways for the larval stages as follows: percent larval mortality was calculated on the number of visible leafmines in relation to the number of pupae collected, and percent pupal mortality was based on the number of pupae collected in relation to emerged adults. Not all treatments were included in the pupal mortality tables because few or no pupae were collected. Mortality data (except for number of emerged adults) were subjected to arcsin transformation prior to analysis by Duncan's new multiple range test, but actual percentages are presented in the tables.

RESULTS AND DISCUSSION

Chromatomyia. syngenesiae Triazophos, PYI'8zophos, and pirimiphos-methyl all prevented egg hatch, or

killed larvae before any visible leafmines appeared (Table L). All insecticides prevented pupation (i.e., killed larvae) when applied to 2 . 4 and 4 . 6 d·old larvae, so no adults emerged from these t.reatments. Also, all materials were effective against 6 ~ 8 d-old larvae, but some pupation occurred. When adults emerged ca. 10 d later, the residual deposit of triazophos, cypermethrin, and pyrazophos on leaves was sufficient to kill them.

Liriomyza tri[olii In the L. trifolii experiments (Tables 2 - 4), the relative effectiveness of a

material was similar whether applied with a hand sprayer or when using the spray chamber, but there often was less mortality of all leafminer stages tested when using the spray chamber, especially with other larvae. This indicated that total spray volume and thoroughness of leaf coverage may affect results obtained with certain insecticides. In the spray chamber, upper leaves were wet while both upper and lower leaf surfaces were sprayed beyond the point of run~off when using the hand sprayer,

When plants were thoroughly sprayed with a hand sprayer, 8D52618 and triazophos either reduced egg hatch, or killed larvae prior to formation of visible leafmines (Table 2). Most pesticides that were effective us. 4 ~ 5 d~old larvae also were effective us. 7 d-old larvae, with 8D52618, triazophos, and pyrazophos generally giving the best control (Table 3). An interesting aspect of these data is the comparison of Tables 3 and 4. Table 3 gives larval mortality (i.e., the no. of pupae us. the no. visible leafmines), while Table 4 shows pupal mortality (i.e., the no. of emerged adults us. the no. pupae collected). For most materials there is little difference in their effectiveness ranking, but for methoprene pupal mortality increased considerably. This chemical is expect.ed to act on the larval~adult transition, rather than directly on the larva.

When the hand sprayer was used to apply pesticides to older larvae, all materials significantly increased pupal mOliality, These results agree with those of Parrella et al. (1982), who pointed out that the sampling method must be tailored to the mode of action of the pesticide. The same could probably be said for the application method.

Table 1. Chromatomyia syngenesiae egg, larval, and adult mortality on chrysanthemum. Littlehampton, England. 1981.

Age group'

2-4 Day 4 - 6 Day 6-8 Day

Rate Egg % % % Treatment (% An L L D Mortality L D P Mortality L D P Mortality A Untreated 0 3.4 1.6 0.4 14 a 4.2 0.6 5.3 7 a 0 0.8 11.9 7 a 34 Triazophos 0.04 0 0 1.1 100 b 0 8.2 0 100 b 0 13.2 1.4 92 b 61 Cypennethrin 0.01 4.4 0 3.3 100 b 0 20.8 0 100 b 0 7.7 2.1 80 b 91 Methomyl 0.05 3.2 0 8.3 100 b 0 15.2 0 100 b 0 7.1 3.0 76 b 10 Pyrazophos 0.02 0 0 2.3 100 b 0 11.9 0 100 b 0 11.1 1.3 92 b 61 Pirimiphos-methyl 0.05 0 0 4.9 100 b 0 17.9 0 100 b 0 7.3 3.0 72b 12

• Means of 10 lcavu/trelltment; L = live larvae. D - dead larvae. P "" pupae, A - emerged aduJu (total). Means in each column followed by the 80me letter are not significantly different (P - 0.05) acoordinr.: to Duncan's new multiple range lelL

t Adults emefjl:ed but died due to residual depolit on leavell,

260 J. Agric. Entomol. Vol. 1, No.3 (1984)

Table 2. Liriomyza trifolii egg and/or young larval mortality on greenhouse chrysanthemum. Wooster, Ohio. 1982.

No. leafmines

Rate Treatment (% An Hand sprayer- 8pray chamber-Untreated 0 38.0 a 18.4 a Permethrin 0.025 43.4 a 19.6 a Cypennethrin 0.01 18.2 b 16.2 a Methoprene 0.26 18.0 b 16.5 a Mcthomyl 0.25 9.2 b Methoprene 0.07 8.6 b 16.5 a Pyrazophos 0.02 7.8 be 5.4 a 8052618 0.02 7.6 be 12.2 a Pirimiphos-methyl 0.025 5.6 be 10.9 a 8052618 0.08 0.2 e 10.6 a Triazophos 0.04 0.0 e 17.5 a 8052618 0.04 0.0 e 8.1 a -!lund sprayer, mellns of five replications (300 goVA, 3168 liter/hll); apro}' chamber, mellns of 10 repliClltions (125 gIiVA.

1:120 liter!ho); meons ""ilh II leiter in comm"" nrc not significantly different {P - 0.051. uccordinK to Dunclin's new llIultiple ranl:e test.

Although pyrazophos and triazophos were effective in killing both C. syngenesiae and L. tri[olii larvae, there was little relationship among the other pesticides used at both GCRI and OARDe. Chromatomyia syngenesiae was apparently susceptible to all pesticides tested. Methomyl controlled C. syngenesiae but was ineffective us. L. tri[olii, despite being used at a 5 X stronger concentration. Methomyl has been implicated in previous leafminer outbreaks in the United States, so the lack of control was not surprising (Oatman and Kennedy 1976). These results are the ftrst comparative data which demonstrate that C. syngenesiae is more susceptible to pesticides than L. tri[olii.

ACKNOWLEDGMENT

We wish to thank SAFE Endowment for providing partial funding for this project.

Table 3. Liriomyza trifolii larval mortality on greenhouse chrysanthemum l Wooster, Ohio. 1982.

Mean % mortality of 4 - 5 and 7 d·old larvae-

Rate 4·5 d-old larvae 7 d-old larvae Treatment (% An Hand sprayert Spray ehamberl Hand sprayed Spray chambed S052618 0.02 92.9 a 74.6 a 81.5 b 47.6 b SD52618 0.04 100 a 82.0 ab 97.9 a 33.2 be S052618 0.08 100 a 90.2 a 96.3 a 55.4 b Triazophos 0.04 100 a 71.4 a 97.4 a 79.5 a Pyrazophos 0.02 100 a 89.5 a 91.2 a 35.8 be Methoprene 0.26 38.8 b 8.0 be 12.3 cd 15.5 ed Methoprene 0.07 31.2 be 24.9 b 0 d l.5 d Methomyl 0.25 23.0 bed 19.4 e Cypermethrin 0.01 7.2 d 0 e 0 d 0 d Permethrin 0.025 12.6 ed 3.9 be 0 d 5.3 d = o Pirimiphos-methyl 0.025 27.0 be 2.2 c 10.0 ed 0 d Untreated 0 12.9 bed ?_.0- e 0 d 2.0 d

- Mum of five Il.'pliClltion.; number. in filch rolumn ""ilh • I~lter in common Iln' not significsolllly different (P - 0.05). according to Duncan', new mullip!l' range 1l':~I, pt'rt't'nl mon'!;I)· bllSl'd on original no. of ,~sible lcafminu 1.". no. pupae rolletled. ArCllin tnnJfonnal;on WllS used prior to analysis, bUI aClu.1 Pl'rCl'ntagcs flT1!'lI!ntl'd.

t :100 csUA. 3168 !ilerlh,.*125 ~aIIA, 1320 Iilu/ha.

~

~

Table 4. Liriomyza trifolii pupal mortality on greenhouse chrysanthemum, Wooster, Ohio. 1982.

Mean % pupal mortality after treatment of 4 . 5 and 7 d·old larvae-

Treatment Rate

(% An 4 - 5 d-old larvae

Hand sprayert Spray chamber: 7 d-old

Hand sprayer t larvae

Spray chamber: !'-SD52618 SD52618

0.02 0.04

#1 #

13.9 #

e # #

46.2 36.1

a a

>:g.o

SD52618 0.08 # # # 47.2 a '" Triazophos 0.04 # # # 69.0 a "o Pyrazophos 0.02 # # # 62.5 a ~ Methoprene 0.26 51.9 a 66.0 ab 88.8 a 59.1 a Methoprene 0.07 40.0 ab 67.6 a 61.3 b 32.9 a ~ Methomyl 0.25 18.1 e - 42.1 be -Cypermethrin Permethrin

0.01 0.025

36.6 abc 28.2 abc

29.2 35.4

e he

44.9 30.6

be e

27.9 40.7

b a

z p

'" Pirimiphos·methyl Untreated

0.025 0

26.2 be 19.3 be

17.9 33.0

e e

32.6 e 11.7 d

30.7 38.3

a a u;

'" - Mellnl of five replicationB; numbers in nch column with a letter in common ar!! not Bignificlntly different (/' ~ O.OS), according to Duncan'. new multiple ranj:ll teBt, percent mortality hnled on .::

originlll no. or PUPIe coUecled VI. no. emeTJed adula. Arclin tr.nlfonnation W/lS used prior to anelYlil. but actual perCentAges an" pres.ented. t 300 laVA, 3168 Iiter!h•. : 12S ,aVA, 1320 liter{h•. § 'fNatment. marked with an -1f: produced few or no pupae.

263 LINDQUIST et al.: Leafminer Control on Chrysanthemum

REFERENCES CITED

Alverson, D. R., and C. S. Gorsuch. 1982. Evaluation of chrysanthemum cult.ivars and insecticides for control of damage by a lellfminer, Uriomyzo tri[a/ii (Diptera: Agromyzidae) . .J. Econ. Entomol. 75: 888-891.

Anonymous. 1980. Effort experience was a surprise. The Grower. 24 July, 1980. p. 31. Gurney, B. and N. W. Hussey. 1974. Chemical control of t.he chrysanthemum leafminer,

Phytomyza syngenesiae (Hardy) (Diptera: Agromyzidae) PI. Pat.h. 23: 127·132. Keil, C. B., and M. P. Parrella. 1983. LirionJyza Infolii on chrysanthemums and celery:

managing an insecticide resistant. population. In Proc. 3rd Conf. on Leafminers. S. L. Poe led·l, PI'. 162-167.

Oatman, E. R., and G. G. Kennedy. 1976. Methornyl induced outbreaks of Liriomyza sativae on tomato. J. Econ. Entomol. 69: 6S7-6GB.

Parrella, M. P., W. \\1. Allen, and P. Morishita. 1981. Leafminer species causes California mum growers new problems. Calif. Agric. 35(9/10): 28-30.

Parrella, M. P., K. L. Robb. and P. Morishita. 1982. Response of Liriomyza tri[olii (Diptera: Agromyzidae) larvae to insecticides, with notes ahout efficney tesl.ing. J. Econ. Ent.omol. 75: 1104-1108.

Price. J. F. 1983. Methods practiced for lenfminer control in Medellin, BogoUl. Colombia. In Proc. 3rd Annual Industry ConI'. on the Leafminer. S. L. Poe led.l, pp. 104·109.

Price, J. F.. and C. D. Stanley. 1983. Gyposphila, Icarminer and parasitoid relationships on two farms of differing pesticide usc patterns. IT! Proc. 3rd Annual Industry Conference on the Lel1fminer. S. L. Poe [ed.], pp. 66-78.

Spencer, K. A. 1973. Agromyzidae (Diptera) of economic importance. Dr. W. Junk B. V.. The Hague. pp. 201-229.

van de Vrie, M.. and F. B. Dirkse. 1982. Biology llnd control of the leafminer, Liri()myza frifolii (Burgess) on glasshouse chrysanthemum. Unpublished Mimeo. Proefstation voor de Bloemisterij, Aalsmeer, The Netherlands. 9 pp.