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EVALUATION OF EXPERIMENTAL INSECTICIDE TREATMENTS IN COLLARD David G. Riley and Alton “Stormy” Sparks Jr. University of Georgia, Tifton Campus Department of Entomology Tifton, GA 31793 dgr@uga.edu Introduction Collards, Brassica oleracea (L.) Acephala group (in this test`Top Bunch'), is the other main Brassica crop, next to cabbage, in Georgia. It is faced with similar multiple pests that attack the leaves, namely, diamondback moth (DBM); Plutella xyllostella, cabbage looper (CL); Trichoplusia ni, and imported cabbage worm (ICW); Pieris rapae. This test evaluated new number compounds from Syngenta, compared to a standard pyrethroid insecticide. The use of new chemistries and product rotations are critical for managing insecticide resistance in DBM. Materials and Methods Collards was transplanted into 2 rows per 6-ft beds on 6 March 2007 and maintained with standard cultural practices at the Lang Farm, Georgia Coastal Plain Experiment Station at Tifton. A total of 500 lbs of 10-10-10 and 300 lbs of 34-0-0 were applied to Tift pebbly clay loam field plots and irrigation was applied regularly with an overhead sprinkler system. Scouting was conducted weekly from 3 April using two samples of 6 plants per plot. Foliar applications of insecticides were made approximately weekly from 6 April to 18 May. Plant tops were harvested from 10 ft of the center of the plot row on 7 and 24 May and plant tops were weighed and categorized as 0=not damaged, 1=slightly damage, 2=moderately damaged, 3=severely damaged by worms or contaminated by whitefly nymphs. Damage ratings >1 were not marketable collards. Data was analyzed using GLM and LSD tests for separation of means (SAS Institute 1990). Results and Discussion All of the treatments except for the Warrior treatment provided excellent control of lepipodteran pests across all species encountered. Even Warrior provided significant control of diamondback moth, but started to lose efficacy by the last sample date. The best treatments in terms of control of Lepidoptera larvae, reduction in damage, and increased marketable yield of collards were all rates of A15397 50/100SC and all rates of A15365 250SC except the lowest rate of 30 grams ai/ha which experienced a significant increase in damage and decrease in marketable yield compared to the high rates. All pest species of Lepidoptera encountered in this test were controlled by A15397 50/100SC and the higher rates of A15365 250SC which resulted in significant increases in marketable yield. 25 Diamondback moth large larva 4/30/07 1.3 a Diamondback moth pupa 4/30/07 3.0 a Diamondback moth 4/30/07 Leps total 4/30/07 Cabbage Looper 5/11/07 Diamondback moth 5/11/07 Treatment - rate per acre 1. Untreated Check Diamondback moth small larva 4/30/07 2.5 a 6.8 a 7.5 a 3.3 a 9.5 a 2. A15397 50/100SC 45 gai/ha 0.0 c 0.5 abc 0.3 c 0.8 cde 2.0 bc 0.0 b 2.5 cd 3. A15397 50/100SC 60 gai/ha 0.3 bc 0.0 c 0.3 c 0.5 de 1.1 bc 0.3 b 3.0 bcd 4. A15397 50/100SC 75 gai/ha 0.0 c 0.3 bc 0.0 c 0.3 e 0.5 c 0.5 b 3.8 bc 5. A15397 50/100SC 90 gai/ha 0.5 bc 0.8 abc 0.5 bc 1.8 bcd 2.0 bc 0.3 b 1.5 d 6. A15365 250SC 30 gai/ha 0.8 bc 0.5 abc 0.3 c 1.5 bcde 1.5 bc 0.8 b 3.3 bc 7. A15365 250SC 40 gai/ha 0.3 bc 1.0 ab 0.5 bc 1.8 bcd 1.8 bc 1.0 b 3.0 bcd 8. A15365 250SC 50 gai/ha 1.0 b 0.3 bc 0.8 bc 2.0 bc 2.3 bc 0.0 b 3.5 bc 9. A15365 250SC 60 gai/ha 0.3 bc 0.8 abc 1.5 b 2.5 b 2.8 b 0.5 b 2.5 cd 10. Warrior/Zeon 1CS 28 gai/ha 0.3 bc 0.5 abc 0.5 bc 1.3 bcde 3.0 b 1.3 b 4.3 b * Means within columns followed by the same letter are not significantly different (LSD, P<0.05). 26 Overall Diamondback moth 3.5 a Imported cabbage worm 1.2 a Leps total Overall 1. Untreated Check Overall Cabbage looper 0.58 a 5.3 a First Damage rating 1.9 a Overall Damage rating 2.2 a Marketable Weight of Collards 11 c 2. A15397 50/100SC 45 gai/ha 0.04 b 1.2 b 0.4 b 1.6 b 0.6 d 1.2 d 35 ab 3. A15397 50/100SC 60 gai/ha 0.17 b 1.7 b 0.2 b 2.0 b 0.7 cd 1.3 cd 28 ab 4. A15397 50/100SC 75 gai/ha 0.13 b 1.9 b 0.3 b 2.4 b 0.6 d 1.3 cd 29 ab 5. A15397 50/100SC 90 gai/ha 0.08 b 1.2 b 0.5 ab 1.8 b 0.8 cd 1.2 d 39 a 6. A15365 250SC 30 gai/ha 0.13 b 1.5 b 0.5 b 2.1 b 0.9 bc 1.5 bc 21 bc 7. A15365 250SC 40 gai/ha 0.25 ab 1.4 b 0.3 b 1.9 b 0.7 cd 1.3 cd 36 ab 8. A15365 250SC 50 gai/ha 0.08 b 1.6 b 0.5 b 2.2 b 0.7 cd 1.1 d 41 a 9. A15365 250SC 60 gai/ha 0.08 b 1.5 b 0.5 b 2.1 b 0.7 cd 1.1 d 37 a 10. Warrior/Zeon 1CS 28 gai/ha 0.38 ab 1.9 b 0.7 ab 3.0 b 1.1 b 1.8 b 20 bc Treatment - rate per acre * Seasonal means within columns followed by the same letter are not significantly different (LSD, P<0.05). 27