Control of Soybean Looper on Soybean with Bacillus Thuringiensis, 1994

Commercial B. thuringiensis products were evaluated against a SL population on soybean in Lafayette Co., Arkansas. Treatments were applied on 9 Sept with a Backpack CO2 sprayer equipped with a two-row boom (1 nozzle per row) using TX-6 nozzles calibrated to deliver 10 gpa. A spreader-sticker, CS-7, was added at the rate of 1.0 ml per gal. Water used for mixing insecticides had a pH of 7.0. A RCB design (with four replicates) was used. Soybeans were planted in late Jun. At application soybeans were primarily in the R-2 developmental stage and were approximately 24 inches in height. Plots were four rows with 20-inch spacing × 100 ft in length. Plots were separated by two-row buffers on their sides and 15 ft buffers on their ends. Treatments were evaluated at 4 and 7 DAT by shaking larvae from plants onto a 1-yd-length cloth spread between the rows. A 6 ft sample was taken from each of 2 rows, and larvae on the cloth were counted. The population contained larvae in all instars. No rainfall occurred during the test. Data were analyzed using ANOVA and LSD procedures.