EFFICACY OF VOLIAM INSECTICIDES AGAINST CATERPILLAR PESTS OF COLLARDS AND EFFECTS OF POST-APPLICATION OVERHEAD IRRIGATION Alton N. Sparks, Jr., Extension Entomologist University of Georgia, Tifton Campus P.O. Box 748 Tifton, GA 31794 asparks@uga.edu Introduction Voliam xpress and Voliam flexi are pre-mix insecticides recently labeled by Syngenta. Both products contain chlorantraniliprole combined with thiamethoxam (Voliam flexi) or lambda-cyhalothrin (Voliam xpress). While both of these products are registered for foliar uses only, both chlorantraniliprole and thiamethoxam have systemic activity when applied in the soil. It is possible that an irrigation or rain event after of foliar application may not have the same adverse effect experienced with non-systemic insecticides. This test was conducted to evaluate the efficacy of Voliam express and Voliam flexi against caterpillar pests of cole crops and the influence of a simulated irrigation event shortly after application. A transplant drench with Durivo was included for comparison. Materials and Methods Collards were transplanted into single rows on six foot beds for this test, but were treated as a 3 foot row. Plots were 20 feet long and were established in a randomized complete block design with four replications. Insecticides evaluated were Voliam flexi 40WG (at 7 oz/ac) and Voliam xpress 1.25ZC (at 9 oz/ac). A row drench treatment with Durivo (at 13 oz/ac) was included as a standard for a systemic application. A non-treated check was included for comparison. The Durivo row drench was applied in 3 liters of water per row in a 4 inch band on 30 July, 2009. Foliar applications of both Voliam products were made with a CO2 pressurized backpack sprayer (60 psi) in 40 gpa, with 3 hollow-cone nozzles per row. Foliar applications, with and without post-application irrigation (wash-off), were made on 31 July and 25 August. Plots assigned to the “wash-off” treatments received overhead watering shortly after application. The first application wash was done with about 3 gallons or water per plot and the second application wash was done with 6 liters per row (both on a roughly 12 inch band over the plants). To monitor insect densities, five randomly selected plants were visually examined for insects in each plot on each sample date. All caterpillars were identified and counted. For damaged plant counts, all plants in each plot were visually examined. Those with moderate or severe feeding damage (obvious holes through the leaves) were counted in each plot. Data were analyzed with the PROC ANOVA procedure of PC-SAS. Where significant differences were detected (P<0.05) means were separated with LSD (P=0.05). 45 Results and Discussion The Durivo drench treatment maintained insect counts below 1 per 5 plants through 28 days after application and provided statistically similar control to the foliar treatments throughout the test (up to 36 days after the drench application). Durivo provided suppression of damage through 28 days after drenching. The foliar treatments and the foliar+washoff treatments performed similarly throughout the test. Pest pressure was light following the first application until 24 days after application, when all the foliar treatments provided a non-statistical suppression of insect counts. Following the second application, all four treatments provided good control through 10 days after application (last counts taken). Damaged plant counts did not show much affect from the foliar treatments as damage was already present prior to the second application (however, all four treatments did show numerical increases by 13 days after the second application; other data has shown similar trends for foliar applications of chlorantraniliprole). The wash-off treatments did not hurt efficacy of the foliar treatments, but did not appear to have the residual activity of the Durivo drench (based on numerical differences in damage on 24 and 27 Aug). 46 Voliam wash-off test, collards, Horticulture Farm, Tifton, Georgia, 2009. Treatment Number of caterpillars (all species) per 5 plants 5 Aug 11 Aug 17 Aug 24 Aug 27 Aug Check 0.00 a 0.00 a 0.00 a 5.00 a 2.75 a V. flexi 0.00 a 0.00 a 0.25 a 1.75 a 0.25 b V. xpress 0.00 a 0.00 a 0.25 a 1.25 a 0.00 b V. flexi+wash 0.00 a 0.00 a 0.00 a 1.50 a 0.00 b V. xpress+wash 0.00 a 0.00 a 0.00 a 3.00 a 0.00 b Durivo drench 0.00 a 0.00 a 0.00 a 0.25 a 0.50 b DAT foliar 5 11 17 24 2 DAT drench 6 12 18 25 28 1 Sept 10.25 a 0.50 b 1.00 b 0.50 b 0.25 b 3.75 b 7 33 4 Sept 9.50 a 0.00 b 0.00 b 0.50 b 1.50 b 1.50 b 10 36 No. damaged plants per plot 24 Aug 27 Aug 7 Sept 5.25 a 6.00 a 9.75 a 2.50 ab 3.50 a 5.00 c 3.75 a 5.00 a 5.25 bc 4.25 a 3.00 a 5.00 c 5.50 a 5.50 a 7.75 ab 0.50 b 1.25 a 6.50 bc 24 2 13 25 28 39 47