Leafminer Populations Research Articles

Control of Beet Armyworms, Pinworms, and Leafminers on Tomatoes, Spring 1996

Abstract Solarset’ tomatoes were transplanted into Rockdale soil plastic mulch beds on 3 Apr, 1996. A RCB design was employed to provide 4 replicates each for 8 treatments comprising a plot size of 4 rows, 30 feet long. Insecticide applications were initiated 4 weeks after transplant and continued on approximately 7-day intervals beginning 1 May. Foliar insecticides were applied using a COz-powered backpack sprayer using 2 nozzles per row at 40 PSI delivering 100 gpa. No phytotoxicity was observed with either product. Evaluations were conducted 24 h after each treatment. BAW larvae were counted on 5 interior plants of the middle two rows of each plot. Tomato pinworm and leafminer larvae were evaluated by examining three trifoliates per plot. Although BAW and leafminer populations were slightly lower than normal, pinworm populations were moderately high.

Evaluation of Insecticides for Control of Leafminers on Lima Beans, 1997

Abstract Eight treatments were evaluated in a research field near Farmington, CA to determine their efficacy in controlling leafminers. The experimental design was a RCB with 3 replications. Plots were 2 rows wide (5ft) by 35 ft. long. Research sprays were applied with a backpack CO2-powered sprayer on 31 Jul (A), 7 Aug (B), 13 Aug (C), and 20 Aug (D) in 20 gallons per acre. In early July, maintenance applications of Orthene 75 SP at .66 lb(AI)/acre and Lannate 90 SP at 1.0 lb(AI)/acre were applied to increase leafminer populations. Treatments were evaluated by removing and examining 25 leaves from the top to the interior of the plant in the center of two treated rows. Pupae were collected from two plastic dinner plates, 26-cm dia, placed in the center of the two treated rows at the base of the plants. Pupae were removed from the plates and placed in 165-ml Dixie cups with lids and held in the lab for 3-4 weeks and then evaluated for adult leafminer emergence, natural mortality, and parasite emergence. Rainfall just before the 21 Aug collection date made that week’s data unreliable for number of pupae.

Impact of Insecticides on Tomato Insects 1996

Abstract Seedlings were transplanted in a sandy loam type soil on 18 June at the University of California’s South Coast Field Station in Santa Ana, California. Experimental plots were 4 rows wide (5-ft centers) by 40 ft long and separated by a 5-ft buffer. The tomato transplants were drip irrigated (water pH 7.2-7.5). Treatments were replicated 4 times in a RCB block design. Weekly applications were initiated at first fruiting. Application dates were 25 Jul, 1, 8, 15, 22, 29 Aug, and 5, 12, 19 Sep. A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, #25 cores, and 50 mesh screens. Operating pressure was 100 psi delivering 100 gpa. Spreader sticker (Leaf Act 80) was included for all treatments at 0.04%, except Fortune AZA and Neemix (+0.5% crop oil) and Aphistar (+ silwet @ 2 oz./lOO gal.). Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 9 by 11 inch trays/replicate from 30 Jul through 18 Sep, inclusive. On 23-25 Sep, 200 mature-green to ripe fruit were harvested from the center 2 rows of each replicate (800 per treatment) and examined for internal damage (primarily by H. zed) and external damage (primarily by S. exigua and K. lycopersicella). Leafminer populations were moderate. Some treatments increased leafminer density as compared to the control.

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).

The role of meteorological parameters on the infestation of rust and leaf miner of groundnut at Akola

ABSTRACT- Effect of meteorological parameters on the incidence of rust and leaf miner of groundnut at Akola, Maharashtra is studied. Both graphical and statistical methods are used as tools for evaluating correlation of meteorological parameters with rust and leaf miner. It is found that rust infestation occurs in the pod ripening stage whereas leaf miner attack extends from pod formation to pod ripening stage of groundnut. Decrease of minimum temperature, relative humidity and increases of sunshine hours a few days back increases rust infestation. Increase in maximum temperature in humid and bright sunshine condition helps to raise leafminer population.
 

Arthropod pest and natural enemy abundance under second-level versus first-level integrated pest management practices in apple orchards: a 4-year study

The authors conceive of second-level integrated pest management (IPM) in apple orchards as involving integration of multiple management tactics across all classes of pests. From 1991–1994, a second-level IPM pilot project was carried out in six commercial Massachusetts apple orchard blocks (2–4 ha) in which pest and natural enemy populations and injuries to fruit were compared with those in adjacent blocks receiving first-level IPM practices (considered to be integration of tactics within a single class of pests). The approach to second-level IPM was use of chemically based tactics for arthropod, disease and weed control during the first part of the growing season (up to mid-June for arthropods) and thereafter use of only biologically based tactics (cultural, behavioral and biological control methods). This article deals with findings on arthropod management. As expected, total injury to fruit by insects causing damage before mid-June did not differ between second-level (4.7%) and first-level (4.8%) IPM blocks. Total injury to fruit by insects active after mid-June averaged about the same (0.5%) in both types of blocks in 1991 and 1992, but in 1993 and 1994 it averaged more in second-level blocks (4.8%) than first-level blocks (1.9%). This was particularly true for Grapholitha prunivora Walker and leafrollers and less so for Cydia pomonella (L.) and Rhagoletis pomonella (Walsh). Among foliar pest arthropods and their natural enemies, populations of aphids and aphid predators and populations of spider mites and mite predators averaged about the same in both types of blocks. Populations of leafminers averaged lower and parasitoids of leafminers averaged greater in second-level blocks. Populations of leafhoppers averaged greater in second-level blocks. Pesticide use against fruit-damaging insects averaged 37% less in second-level than in first-level blocks, but against foliar-damaging arthropods, it was not less. Some refinements of second-level IPM tactics for arthropod control are needed before second-level IPM practices can be recommended broadly to commercial growers in New England as an economical and reliable alternative to first-level IPM.

Impact of Insecticides on Tomato Insects 1994

Abstract Seedlings were transplanted in a sandy loam type soil on 16 June at the University of California‘s South Coast Field Station in Santa Ana, California. Experimental plots were 4 rows wide (5-ft centers) by 40 ft long and separated by a 5-ft buffer. The tomato transplants were sprinkle irrigated for 1 week, and drip irrigated thereafter (water pH 7.2-7.5). Treatments were replicated 4 times in a RCB design. Weekly applications were initiated at first fruiting. Application dates were 21, 28 Jul, 4, 10, 17, 25 Aug, 1 and 8 Sep. (except Avid which was applied on 21, 28 Jul and 17 and 25 Aug.) A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, #25 cores, and 50 mesh screens. Operating pressure was 100 psi delivering 100 gal/acre. Spreader sticker (Leaf Act 80) at 0.04% was included for all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 9 by 11 inch trays/replicate from 26 Jul through 6 Sep., inclusive. On 12-13 Sep., 200 mature-green to ripe fruit were harvested from the center 2 rows of each replicate (800 per treatment) and examined for internal damage (primarily H. zea) and external damage (primarily S. exigua and K. lycopersicella). Leafminer populations were moderate early, then high late in this test. Some treatments increased leafminer density as compared to the control. Beet armyworm and tomato pinworm populations were moderate and tomato fruitworm populations were high. No phytotoxicity was observed in any treatment.

Effect of Insecticides on Tomato Insects 1995

Abstract Seedlings were transplanted in a sandy loam type soil on 21 June at the University of California’s South Coast Field Station in Santa Ana, California. Experimental plots were 4 rows wide (5-ft centers) by 40 ft long and separated by a 5-ft buffer. The tomato transplants were drip irrigated (water pH 7.2-7.5). Treatments were replicated 4 times in a RCB design. Weekly applications were initiated at first fruiting. Application dates were 27 Jul, 3, 10, 16, 24, 30 Aug, and 7, 14 Sep. (except Agrimek which was applied on 27 Jul 3, 24, 30 Aug, and Agrimek + Lannate in which Lannate was applied every wk). A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, #25 cores, and 50 mesh screens. Operating pressure was 100 psi delivering 100 gal/acre. Spreader sticker (Leaf Act 80) at 0.04% was included for all treatments. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 9 by 11 inch trays/replicate from 1 Aug through 12 Sep., inclusive. On 18-21 Sep., 200 mature-green to ripe fruit were harvested from the center 2 rows of each replicate (800 per treatment) and examined for internal damage (primarily H. zea) and external damage (primarily S. exigua and K. lycopersicella). Leafminer populations were low early, then moderate late in this test. Some treatments increased leafminer density as compared to the control. Beet armyworm and tomato pinworm populations were moderate as were tomato fruitworm populations. No phytotoxicity was observed in any treatment.

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.

ミカンハモグリガの薬剤抵抗性とその検定法

The susceptibility of two populations of the citrus leafminer, Phyllocnistis citrella, collected from Matsubase in Kumamoto Prefecture and Naruto in Tokushima Prefecture, to several insecticides was determined by field tests and laboratory bioassay. Citrus leaves infested with 1st and 2nd instar larvae were dipped into insecticide solutions and kept in petri dishs containing wet filter paper at 25°C. The mortalities were determined 48h. The Matsubase population was resistant to fenvalerate (LC50=30.1ppm) and permethrin (LC50=5.27ppm), but the Naruto population was susceptible. The susceptibility to phosmet was low in the Matsubase (LC50=3, 212ppm) and Naruto populations (LC50=150ppm). These results are consistent with the trend found in field tests with insecticides to control P. citrella.

Vegetative Flush Development and Leaf Area Contribution to Citrus Canopies

The recent infestation of Florida citrus by the Asian citrus leafminer required that more information be obtained about the time interval for a flush to expand and the leaf area contributed by flushes in seasons when leafminer populations are likely to increase and cause leaf area loss. Time for leaf and shoot expansion was determined for spring and summer flush. Leaf area contribution from previous-year and current flushes was determined by seasonal tagging and measuring leaf area for flush in frame areas of 1/4 m2 surface projected to the center of the tree. Flush of 1/3 m length required 30 days to expand from first leaf feathers to full expansion. Summer flush in 1994 was 40% to 45% of total leaf area. Spring and previous year's flush averaged 20% each. Fall flush contributed 5% to 12% to leaf area, more on young, low-bearing trees. Summer flush resulted in more canopy leaf area and previous year's flushes less leaf area than expected by the end of the growing season.

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.

Foliar Sprays to Control Insects on Fall Tomatoes, 1994

Abstract Tomatoes were transplanted on 26 Jul at the Eastern Shore Agricultural Research and Extension Center, Painter, VA. Each plot consisted of a single 25 ft row with 5 ft spacing, bordered on each side by an untreated guard row, and replicated four times in a randomized, complete block design. Treatments were applied on the dates indicated in the table using a 3 hollow cone nozzle boom backpack sprayer delivering 45 gal water/acre at 40 psi. A 6-ft section (30 sq ft) of each plot was flagged off for hand harvesting. Fruit at the “breaker” stage or riper was harvested on 29 Sept and 20 Oct. Numbers of marketable and worm-damaged fruit and calculated yields/acre for the combined two harvests are recorded in the table. Damage from all three worm species is similar and no attempt was made to separate the damage according to species. Worm pressure was moderate to heavy with peak moth flights occurring in mid-Aug through mid-Sept, as determined by the black light trap at Painter, VA. Dimethoate and AgriMek were applied for the first spray on the plots indicated in the table to control leaf miners. XenTari was applied on the remaining spray dates on these plots because the leaf miner population declined to well below threshold levels after 6 Sept.

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.

Alternation of bottom-up and top-down regulation in a natural population of an agromyzid leafminer, Chromatomyia suikazurae.

The population dynamics and the relative importance of bottom-up and top-down effects in a plant-leafminer-multiparasitoid interaction was studied between 1981 and 1990 in a natural forest in Kyoto, Japan. The leafminer, Chromatomyia suikazurae (Agromyzidae, Diptera), passed two generations (G1 and G2) on Lonicera gracilipes (Caprifoliaceae). The G1 population in February was free from parasitoid attack, and the mortality in G1 was mainly caused by resource limitation. Intraspecific competition for resources occurred at the larval stage in G1, and the larval mortality was density-dependent. The G1 adult density was resource-limited (the number of newly opened leaves), and its variability was lower than that of G2. The G2 population in April was not resource-limited but subject to intense attack by a species-rich parasitoid complex, and thus total mortality was much larger than that in G1. Significant density dependence was detected not in larval but in pupal mortalities, which were mainly caused by parasitism by parasitoids that attacked the pupa. The host population alternately experienced "bottom-up" effects during the larval stage in G1 and "top-down" effects during the pupal stage in G2. Overall population fluctuation was non-cyclic and mainly due to climatically-induced fluctuation of available plant resources in G1.

Structure, organization, and response of a species-rich parasitoid community to host leafminer population dynamics.

The parasitoid community dynamics of an agromyzid honeysuckle leafminer, Chromatomyia suikazurae (Agromyzidae, Diptera) were studied between 1981 and 1990 in a natural forest in Kyoto, Japan. The parasitoid fauna composed three koinobionts (all larval-pupal solitary parasitoids) and 22 idiodiont species (11 larval solitary, nine pupal solitary and one pupal gregarious). The parasitoid community was dominated by early-attacking oligophagous braconid koinobionts at early periods, but was gradually displaced by late-attacking polyphagous eulophid idiobionts. Accordingly, the diversity index of the parasitoid community peaked at an intermediate point in the intra-generational succession. The succeeding attack-in-waves by the late-attacking idiobionts greatly reduced not only the survival rates of early-attacking parasitoid larvae but also the survival rates of hosts. The density-dependence observed in the host pupal mortality was thought to result from density-dependent host-switching by a keystone polyphagous pupal idiobiont parasitoid, Chrysocharis pubens, whereas high host pupal mortality was potentially attained by an early-attacking koinobiont braconid. Supposed aggregation of polyphagous parasitoids at high host density resulted in intense within-host competition and in an increase of host-feeding attack, both of which contributed to low emergence rates of parasitoids at high host densities. Parasitoid emergence rates were also reduced at low host densities, probably by inter- and intra-specific hyperparasitism among oligophagous parasitoids for limited hosts. The regulation effects of the species-rich parasitoid community upon the host population dynamics are thought to derive from succeeding attack-in-waves by polyphagous late-attacking idiobionts, especially by the keystone species.

Impact of Insecticides on Insects On Tomatoes, 1993

Abstract Seedlings were transplanted in a sandy loam type soil on 14, 15 Jun at the University of California’s South Coast Field Station in Santa Ana, California. Experimental plots were 4 rows wide (5-ft centers) by 35 ft long and separated by a 5-ft buffer. The tomato transplants were sprinkle irrigated for 1 week, and drip irrigated thereafter (water pH 7.2-7.5). Treatments were replicated 4 times in a randomized complete block design. Weekly applications were initiated at first fruiting. Application dates were 27 Jul, 3, 10, 19, 26 Aug and 2, 9 Sep and 1 Oct. A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks. #25 cores, and 50 mesh screens. Operating pressure was 100 psi delivering 100 gal/acre. Spreader sticker (Leaf Act 80) was included for all treatments at 0.04%. Except for the two Rohm Haas treatments, which used Latron at .06%. Leafminer populations were evaluated by weekly counts of leafminer prepupae and pupae in four 9 by 11 inch trays/replicate from 2 Aug through 8 Sep, inclusive. On 13-14 Sep, 200 mature-green to ripe fruit were harvested from the center 2 rows of each replicate (800 per treatment) and examined for internal damage (primarily H. zea) and external damage (primarily S. exigua and K. lycopersicon).

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.

Control of the Serpentine Leafminer on Chrysanthemum Under Greenhouse Conditions, Winter 1993

Abstract Chrysanthemums were obtained as rooted cuttings and potted in 15 cm pots in a greenhouse at UCR and allowed 8 wk growth (25-30 cm tall) before use. During wk 8, the plants were exposed to heavy populations of leafminers. By wk 10, all plants were moderately infested with leafminers. To ensure an equal distribution of leafminers/treatment, plants infested with approximately equivalent numbers were assigned to each treatment (4 plants/treatment). Azadirachtin treatments were applied at 40 psi to runoff using a hand sprayer. The NTN 33893 2.5%G and 240F were applied as soil treatments and drenched into the soil with approximately 250 ml of water. Pre-treatment counts and treatment applications were made on the same day (day 0). Posttreatment counts (the number of adults emerging from pupae) were taken 24 DAT. Number of emerging adults were expressed as a mean percent change from the pre-treatment count and analyzed using ANOVA. As individual leafminers were not held on isolated leaves for a specific period of time, more eggs successfully hatched than were counted in the pretreatment count; thus certain treatments showed positive percentage population increases.