Liriomyza Species Research Articles

Identification of economically important Liriomyza species by PCR‐RFLP analysis*

Only adult males of Liriomyza bryoniae, L. huidobrensis, L. sativae and L. trifolii can be identified with certainty on basis of their genitalia. Female adults, pupae and larvae can only be identified on the level of groups of species (L. bryoniae and L. huidobrensis vs. L. sativae and L. trifolii). Species identification in all developmental stages is possible using molecular biological techniques. Our method is a PCR amplification of a 790‐bp fragment of mitochondrial cytochrome oxidase II (COII) DNA followed by RFLP analysis. The method was tested on single larvae, pupae and adults and proved to be applicable to these three life stages. The specificity of the assay was assessed by comparing the results of the PCR‐RFLP analysis with those of morphological analysis using 60 Liriomyza specimens. Molecular and morphological identification agreed for all specimens analysed. PCR‐RFLP is a powerful diagnostic tool for rapid and reliable identification of all life stages of economically important Liriomyza species.

Can greenhouses eliminate the development of cold resistance of the leafminers?

Latitudinal patterns for quantitative traits in insect are commonly used to investigate climatic adaptation. We compare the cold resistance of the leafminer (Liriomyza sativae) pupa among populations distributed from tropical to temperate regions, incorporating the thermal overwintering limit of the insect's range. The patterns of cold resistance for northern and southern populations differ. The southern populations significantly increased their cold resistance with latitude, showing a latitudinal pattern independent of seasons, acclimation regimes, and assay methods. In contrast, the northern populations showed no stable patterns; they were always intermediate in cold hardiness between the low-latitude and high-latitude populations within the overwintering limit. Integration of these data with those of the biologically similar congeneric leafminer, L. huidobrensis, suggests that a pattern shift in stress tolerance associated with the overwintering range limit is probably a general adaptive strategy adopted by freeze-intolerant species that have a high-latitude boundary of distribution, but can only overwinter and develop in protected greenhouses in harsh seasons. Considering the widespread availability of greenhouses for overwintering insects in northern China, we speculated that the large-scale existence of thermally-buffered microhabitats in greenhouses might eliminate the development of cold resistance of the leafminer populations. However, results suggest a strong selection for increased cold resistance for natural populations of Liriomyza species at higher latitudes that can overwinter in the field, but not for populations at latitudes above the thermal limit. Thus, habitat modification associated with greenhouses can limit gene flow and reduce cold tolerances even at latitudes above where the leafminers can overwinter in the field.

トマトハモグリバエ，マメハモグリバエおよびナスハモグリバエ（双し目：ハモグリバエ科）の殺虫剤感受性

The insecticide susceptibility of the vegetable leafminer, Liriomyza sativae Blanchard, the serpentine leafminer, L. trifolii (Burgess), and the tomato leafminer, L. bryoniae (Kaltenbach), on kidney bean leaves were evaluated at 25°C under a 15L–9D photoperiod. Susceptibility to the tested insecticides varied among the developmental stages, species, and populations of the leafminer. Among the 25 insecticides tested on second instar larvae using an insecticide spraying tower, chlorpyrifos, isoxathion, cartap, thiocyclam, cyromazine, emamectin benzoate, pyridalyl, and spinosad were more toxic on the three Liriomyza species. Among the 20 insecticides tested on adult leafminers using the leaf dipping method, cartap and thiocyclam produced high mortality in the three Liriomyza species. The application of cartap, thiocyclam, emamectin benzoate, and spinosad reduced the number of feeding and oviposition punctures made by female adults of the three Liriomyza species on the leaves. None of the insecticides examined significantly affected the egg mortality of any of the three Liriomyza species.

トマトハモグリバエ，マメハモグリバエおよびナスハモグリバエ（ハエ目：ハモグリバエ科）の発育に及ぼす寄主植物の影響ならびに寄主植物選好性

The immature developmental period and adult emergence rate of Liriomyza sativae, L. trifolii, and L. bryoniae on 16 plant species were examined. Kidney bean (developmental period: 16.5 d), eggplant (16.4 d), and garland chrysanthemum (16.9 d) were more suitable for L. sativae than other plants; kidney bean (16.5 d), soybean (16.4 d), tomato (16.7 d), eggplant (16.2 d), mizuna (16.2 d), mibuna (17.0 d), okra (17.4 d), and garland chrysanthemum (16.3 d) were more suitable for L. trifolii than other plants; soybean (19.0 d), pumpkin (19.3 d), tomato (19.2 d), eggplant (18.3 d), komatsuna (18.9 d), mizuna (18.3 d), mibuna (19.1 d), okra (18.4 d), garland chrysanthemum (18.9 d), and welsh onion (18.0 d) were more suitable for L. bryoniae than other plants. The adult emergence rates on okra and garland chrysanthemum for L. sativae, that on komatsuna and melon for L. trifolii, and that on welsh onion and komatsuna for L. bryoniae were high. In the choice oviposition experiments with kidney bean, cucumber, eggplants, and komatsuna, L. sativae preferably oviposited into the kidney bean, and there was no host oviposited prominently by the L. trifolii or L. bryoniae females. In the choice oviposition experiments with kidney bean, cucumber and tomato, there was no significant difference in the number of eggs laid by each Liriomyza species among the three hosts.

Implication of pupal cold tolerance for the northern over-wintering range limit of the leafminer Liriomyza sativae (Diptera: Agromyzidae) in China

This study investigated the cold tolerance of a laboratory-reared population and latitude-separated populations of the leafminer Liriomyza sativae in China in terms of low-temperature survival rate and supercooling capacity. Pupae of the laboratory-reared population are susceptible to freezing temperatures. The supercooling point of the pupae varied at a maximum of up to 10°C among the geographic populations. Both acclimation of the pupae at 5 and 10°C significantly increased the cold survival rate of laboratory-reared and field-collected populations. But the field population had a more active response to the same acclimation regime. Combining the experimental data with previous field investigations, the −2°C isotherm of the minimum mean temperature of January was proposed as the leafminer's over-wintering range limit. Meanwhile, with the widespread availability of greenhouses as a source of re-infestation in northern China, the leafminer's natural border of distribution should be determined by the minimum temperature in warm seasons. Our results suggest that biologically similar Liriomyza species may cope with the intensifying cold stress along the latitude by adopting a mixed cold-tolerance strategy, which is closely associated with the greenhouse microhabitats. The physiologically based modeling of the over-wintering limit provides a tool for guiding the management for greenhouse pests and predicting the source of pest infestation.

Toxicity of chemicals commonly used in Indonesian vegetable crops to Liriomyza huidobrensis populations and the Indonesian parasitoids Hemiptarsenus varicornis, Opius sp., and Gronotoma micromorpha, as well as the Australian parasitoids Hemiptarsenus varicornis and Diglyphus isaea.

Liriomyza huidobrensis (Blanchard) and Liriomyza sativae (Blanchard) are important pests of vegetable crops in Indonesia and are likely to spread to neighboring countries. Three pesticides (dimehypo, abamectin, and cyromazine) are currently used to control these pests, but there is little information on their effectiveness against field populations and on their impact on parasitoids controlling Liriomyza species. The toxicity of these chemicals to L. huidobrensis and three common parasitoids (Hemiptarsenus varicornis Gerault, Opius sp., and Gronotoma micromorpha Perkins) was therefore evaluated in Indonesia with mortality laboratory assays. All three chemicals were effective against larvae of three populations of L. huidobrensis with different histories of chemical exposure. Dimehypo caused mortality in adult Opius sp., G. micromorpha, and H. varicornis, whereas abamectin was toxic only at concentrations substantially higher than the field rate. Cyromazine did not influence survival of the parasitoids. A commonly used fungicide, mancozeb, had no impact on parasitoid mortality. Trials were repeated with a strain of H. varicornis from Australia and a different parasitoid (Diglyphus isaea) recently found in Australia. Neither parasitoid was influenced by mancozeb or cyromazine. Abamectin applied at field rates caused some mortality among the adults of both species, but was less toxic than chlorpyrifos. Abamectin produced lower LC50s against Australian H. varicornis than against Indonesian H. varicornis. These results suggest that cyromazine can be incorporated into Liriomyza control programs in Indonesia that conserve parasitoids, whereas dimehypo and abamectin need to be used cautiously. Local Australian parasitoids should help control L. huidobrensis as long as only cyromazine and nontoxic fungicides are applied.

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The developmental period, reproductive potential, and adult longevities of Liriomyza sativae Blanchard, L. trifolii (Burgess), and L. bryoniae (Kaltenbach) were examined on kidney beans. The total developmental period (oviposition to adult emergence) decreased with increasing temperature between 15°C and 30°C in L. sativae and L. trifolii, and between 15°C and 25°C in L. bryoniae with a 15L–9D photoperiod. A significantly longer developmental period was found in each species with 10L–14D than with 15L–9D photoperiods at 18°C. The developmental zeros for total development of L. sativae, L. trifolii, and L. bryoniae were 10.7, 9.8, and 8.1°C, respectively. The effective accumulative temperatures of L. sativae, L. trifolii, and L. bryoniae were 248.1, 251.3, and 316.5 day-degrees, respectively. The adult emergence rates for all three species were highest at 25°C. The total fecundity was highest for L. sativae among the three Liriomyza species. Adults of L. sativae lived significantly longer than those of L. trifolii and L. bryoniae. The intrinsic rates of natural increase for L. sativae, L. trifolii, and L. bryoniae were 0.21, 0.17, and 0.12, respectively.

Interspecific and intraspecific differences in two Liriomyza leafminer species in California

AbstractIn recent years, the pest status of Liriomyza trifolii (Burgess) and L. huidobrensis (Blanchard) (Diptera: Agromyzidae) has changed in California, as well as other areas of the world. In California, L. huidobrensis has become the predominant Liriomyza species in valleys along the central coast, while L. trifolii remains the predominant species in southern California. To investigate possible reasons for this change in status, differences in host plant use and reproductive success of intraspecific populations were examined for Liriomyza trifolii and L. huidobrensis from both central and southern California. The southern L. trifolii fed, oviposited and reproduced successfully on all five hosts tested, but the central population fed significantly less on all hosts and was restricted to reproducing on pepper only. With the exception of pepper, southern L. trifolii had significantly greater larval survival on all hosts than central L. trifolii. In contrast, the central L. huidobrensis population had greater reproductive success than the southern population of that species on all hosts plants tested. However, pepper was not a suitable host for either L. huidobrensis population. Both species showed positive assortative mating, with homotypic mating occurring more frequently than heterotypic mating; however, the difference between L. trifolii populations was much more pronounced than between L. huidobrensis populations. These data indicate that central and southern California populations of each species are distinct biotypes. Furthermore when coupled with previous genetic data, our results suggest the possible existence of cryptic species within L. trifolii.

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Search for molecular markers linked to Liriomyza trifolii resistance in tomato

Resistance to many arthropods, including Liriomyza species, is known to be present in accessions of Lycopersicon hirsutum (f. typicum or f. glabratum). From the cross L. esculentum cv. Moneymaker and L. hirsutum f. glabratum G1561 100 F2 plants were screened in a no-choice test for resistance to Liriomyza trifolii. The Bulked Segregant Analysis approach was used to find Random Amplified Polymorphic DNA markers linked to resistance. Two markers were located on chromosome 2. Restriction Fragment Length Polymorphisms constructed a more detailed genetic linkage map for part of chromosome 2. Kruskal-Wallis analysis showed that this chromosome harbored a Quantitative Trait Locus (QTL) for number of pupae, number of mines and damage. At least one major QTL is essential for resistance and this QTL is located on chromosome 2 nearby the location of the tomato probe TG451.

Effect of Insecticides on Celery Insectsc, 1995

Abstract Celery was transplanted in a sandy loam soil on 29-30 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a RCB design. Applications were weekly from 5 Oct through 30 Nov (total of 9 applications for all chemicals except Avid and Avid + Lannate). Actual dates of applications were: 5, 12, 19, 26 Oct, and 3, 9, 16, 21, 30 Nov. Avid was applied on 5, 12 Oct and again on 3, 9, 30 Nov. The Avid + Lannate treatment was the same except that Lannate was applied on 19, 26 Oct and 16, 21 Nov. All chemicals were applied by a tractor-mounted boom sprayer operated at 125 psi. Nozzles were 4 per bed and carrier (H2O) was at 100 gpa. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5 1/2 X 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 16, 25, 31 Oct and 8, 16, 20, 30 Nov. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of BAW populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (6-7 Dec).

Influence of Liriomyza species (Diptera: Agromyzidae) and their host plants, on oviposition by Opius dissitus females (Hymenoptera: Braconidae)

SummaryTwo factors, among others, influence the oviposition of Opius dissitus Muesebeck. The first was the host species, the second the plant upon which the pest host larvae develop. O. dissitus females prefer Liriomyza trifolii (Burgess) larvae over those of L. huidobrensis (Blanchard). O. dissitus females were more attracted to the larvae of L. trifolii or L. huidobrensis when these were present on courgette rather than tomato or lettuce.

Impact of Insecticides on Celery Insects, 1994

Abstract Celery was transplanted in a sandy loam soil on 30-31 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Applications were weekly from 6 Oct through 21 Nov (total of 8 applications for all chemicals except Avid and Avid + Xentari). Actual dates of applications were: 6, 13, 20, 27 Oct, and 3, 10, 17, 21 Nov. Avid was applied on the first two dates and again for dates 5-6. The Avid + Xentari treatment was the same except that Xentari was applied on dates Avid was not. All chemicals were applied by a tractor-mounted boom sprayer operated at 125 psi. Nozzles were 4 per bed and carrier (H2O) was at 100 gal/ac. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5 ½ X 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 15, 25 Oct and 1, 8, 15, 21, 28 Nov. The number of dead adult parasites of1 Liriomyza species was recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (29-30 Nov). Beet armyworm and black cutworm damage were recorded separately.

Chemical Trials and Effects on Insects in Celery, 1993

Abstract Celery was transplanted in a sandy loam soil on 17 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Applications were weekly from 30 Sep through 24 Nov (total of 9 applications for all chemicals except Avid and Avid + Lannate). Actual dates of application were: 30 Sep, 6, 14, 20, 27 Oct, and 3, 10, 17, 24 Nov. Avid was applied on the first two dates and again for dates 6-9 in Nov. The Avid + Lannate treatment was the same except that Lannate was applied on dates 3-5. All chemicals were applied by a tractor-mounted boom sprayer operated at 125 psi. Nozzles were 4 per bed and carrier (H20) was at 100 gal/acre. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four SVi × 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 5, 13, 19, 27 Oct and 2, 9, 16 Nov. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (30 Nov). Beet army worm and black cutworm damage were recorded separately.

Composition, Seasonal Abundance, and Parasitism of Liriomyza (Diptera: Agromyzidae) Species on Lettuce in Arizona

Liriomyza trifolii (Burgess) and L. sativae Blanchard were the leafminer species found in commercial and experimental plantings of lettuce in the Yuma Valley, AZ. L. trifolii was the dominant species observed in commercial lettuce fields in fall surveys, although populations did not reach damaging levels. In experimental plots, L. sativae was the principal species observed. The sharp contrast in Liriomyza species composition between lettuce grown in commercial and experimental plots was likely a reflection of pesticide-use patterns in commercial lettuce fields. Seasonal abundance and parasitism of leafminers in experimental plantings of lettuce from 1990 to 1992 varied with temperature and planting date. Adults, active larvae, and mines with dead or parasitized larvae were most abundant during the fall growing season. Edible leaves and heads were not mined at harvest. Populations in winter and spring plantings occurred at relatively low densities, likely in response to cooler temperatures and parasitism. The parasitoid complex associated with Liriomyza in fall lettuce primarily consisted of Opius spp. and Chrysocharis parksi Crawford, whereas Diglyphus spp. occurred at lower densities. Natural suppression of leafminer populations by parasitoids and other mortality factors appeared to be important for maintaining Liriomyza populations below damaging levels.

Chemical Trials and Effects on Arthropods in Celery, 1992

Abstract Celery was transplanted in a sandy loam soil on 3 Sep at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Weekly application dates included 15, 22, 29 Oct, 5, 12, 19, 25 Nov and 3, 10 Dec. All chemicals were applied by a tractor-mounted boom sprayer operated at 100 psi. Nozzles were 4 per bed and carrier (H20) was at 100 gal/acre. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5.5 × 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 20, 28 Oct, 4, 11, 18, 23 Nov and 2, 9 Dec. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (14 Dec). Beet armyworm and black cutworm damage was recorded separately.

Chemical Trials and Impact on Insects in Celery, 1991

Abstract Celery was transplanted in a sandy loam soil on 15 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in a randomized complete block design. Weekly application dates included 26 Sep, 3, 10, 17, 24, 30 Oct and 7, 14 Nov. All chemicals were applied by a tractor-mounted boom sprayer operated at 100 psi. Nozzles were 4 per bed and carrier (H20) was at 100 gal/acre. Disc-type cone nozzles incorporated D3 orifice discs, #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam®) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5.5 × 11 inch trays/replicate when the plants reached a suitable height. Actual sampling dates were 2, 9, 16, 23, 30 Oct and 5,13 Nov. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (20 Nov). Beet armyworm, and black cutworm damage were recorded separately.

Resistance to Beet Armyworm, Hemipterans, and Liriomyza spp. in Lycopersicon Accessions

Accessions of Lycopersicon esculentum var. cerasiforme (Dun.) A. Gray (cer) and L. pimpinellifolium (Jusl.) Mill. (pimp), sustained significantly less damage to fruit by beet armyworm [Spodoptera exigua (Hiibner)] than standard cultivars and breeding lines of L. esculentum Mill. (esc) under natural infestations in 1990 and 1991 in southern California. The dwarf vine cherry cultivar Tiny Tim also sustained less damage than the standards. Accessions of esc with various monogenic mutations sustained at least as much beet armyworm damage as did standard cultivars. The percentage of fruit damaged was significantly correlated with vine weight, weight per fruit, number of fruit, and the fruit-foliage weight ratio (Pearson's coefficients, respectively: -0.533, 0.450, -0.483, 0.390, n = 37). In laboratory assays, survival of beet armyworm was significantly lower (5% of susceptible& growth rates were significantly lower, and development time was significantly longer on the fruit of resistant `Tiny Tim' and LA 1320 cer than the fruit of 11 other test lines. There were no substantial differences in beet armyworm survival on the foliage of the test lines. In the field trials, there were also significant differences among the test lines in damage by Liriomyza species and hemipteran pests. Lines with genes for increased densities of nonglandular leaf trichomes (especially LA 1663) were generally less damaged by Liriomyza than other lines. Damage by hemipterans was correlated with vine and fruit size, fruit count, and fruit-foliage weight ratio in 1991, but high intraseason variability prevented clear identification of test lines resistant to these pests.

Chemical Trials and Effects on Arthropods in Celery, 1990

Abstract Celery was transplanted in a sandy loam soil on 15 Aug at the University of California’s South Coast Field Station. The plants were sprinkler irrigated for three weeks and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots wee four beds wide (two rows per bed on 40-inch centers) by 40 ft and separated by a 5 ft buffer with four replicates of each treatment in randomized complete block design. Weekly application dates included 26 Sep, 2, 12, 16, 23, 30 Oct, and 6, 13 Nov. All chemicals were applied by a tractor-mounted boom sprayer operated at 100 psi. Nozzles were 4 per bed and carrier (H20) was at 100 gal/acre. Disc-type cone nozzles incorporated D3 oriftce discs, #23 or #25 cores and 50-mesh screens. All treatments received spreader-sticker. Antifoam (No-Foam°) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5.5 × 11 inch trays/replicate when the plants reached a suitable height. The number of dead adult parasites of Liriomyza species was recorded in the same manner as for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants per replicate (100/treatment) from the center two rows of each replicate at harvest (20 Nov). Beet armyworm and black cutworm damage were recorded separately.

Chemical Trials and Effects on Arthropods in Celery, 1989

Abstract Celery was transplanted in a sandy loam soil on 11 Aug at the University of California's South Coast Field Station. The plants were sprinkler irrigated for 3 wk and drip irrigated (water pH 7.2-7.5) thereafter. Experimental plots were 3 beds wide (2 rows/bed on 40-inch centers) by 50 ft and separated by a 5 ft buffer with 4 replicates of each treatment in randomized complete block design. Weekly application dates included 22, 28 Sep, 5, 12, 19, 26 Oct and 3, 10, 16 Nov. All chemicals were applied by a tractor-mounted boom sprayer operated at 100 psi. As plant height and foliage density increased, nozzles varied from 2—4 per row and carrier (H20) increased from 50 gal/ac (22 Sep) to 100 gal/ac (28 Sep on). Disc-type cone nozzles incorporated D3 orifice discs, #23 or #25 cores and 50-mesh screens. All treatments received spreadersticker. Antifoam (No-Foam) was used with all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 5'/2 × 11 inch trays/replicate when the plants reached a suitable height. Acutal sampling dates were 27 Sep, 4, 11, 18, 25 Oct and 1, 9, 15 Nov. The number of dead adult parasites of Liriomyza species were recorded in the same manner and on the same dates listed for pupal counts. Evaluation of Lepidoptera populations was based on number of damaged plants found in 25 plants/replicate (100/treatment) from the center two rows of each replicate at harvest (20 Nov). Beet armyworm and black cutworm damage were recorded separately.