EVALUATION OF FOLIAR INSECTICIDE EFFICACY AGAINST SOYBEAN LOOPER IN SOYBEANS, 2008

Three field trials evaluated selected foliar insecticides against soybean looper (SBL) on R5 soybeans at the Macon Ridge Research Station (Franklin Parish). Soybean seed were planted into a Gigger-Gilbert silt loam soil on 29 May, 10 Jun, and 28 May in trials 1, 2 and 3, respectively. Plot size was three-four rows (40-inches on centers) x 50 ft with a minimum of five replications in each trial. Insecticides were applied with a high-clearance sprayer and compressed air system calibrated to deliver 6 gpa through TeeJet TX-6 hollow cone nozzles (2/row) at 55 psi. In Trial 1, insecticides were applied on 17 Aug, and post-treatment evaluations were made on 19 Aug (2 DAT), 22 Aug (5 DAT), 24 Aug (8 DAT), and 1 Sep (15 DAT). In Trial 2, insecticides were applied on 17 Aug, and post-treatment evaluations were made on 19 Aug (2 DAT), 22 Aug (5 DAT), 24 Aug (8 DAT), and 1 Sep (15 DAT). In Trial 3, insecticides were applied on 26 Aug, and post-treatment evaluations were made on 28 Aug (2 DAT), 1 Sep (5 DAT), and 5 Sep (9 DAT). Insecticide efficacy was measured by making 25 sweeps with a sweep net (15 inches diameter) in each plot and recording the number of SBL larvae. Soybean seed yield was recorded in Trial 3 by mechanically harvesting two rows of each plot on 13 Oct. Data were subjected to ANOVA and means separated according to DNMRT. Rainfall of 15 inches (Hurricane Gustav) was recorded on 3 Sep and reduced SBL at 9 DAT in all treatments of Trial 3.