Toxicity of Bacillus Thuringiensis Products Against Budworm and Bollworm in Cotton, 1992

Cotton was planted 10 Apr at the Wiregrass Experiment Substation in Headland, AL, in 8-row plots (36 inch centers) × 75 ft long with 25 ft alleys. Treatments were arranged in a RCBD with 4 replications. Applications were made with a high-clearance sprayer calibrated to deliver 8 gal/acre using Teejet TX10 hollow cone tip nozzles on 18-inch spacing at 55 psi and 5 mph. Water pH was 7.2-7.4 and Prime Oil was used as a spreader/sticker at recommended rates. Foliar treatments were applied 7 times (7, 10, 20, 24, 31 Jul and 5, 12 Aug) followed by 1 blanket overspray of Karate on 20 Aug in order to preserve the results of the microbial treatments. Treatments were evaluated 7 times (10, 14, 23-24, 28-29 Jul and 4-5, 10-11, 17-18 Aug) at 3-5 DAT for the presence of eggs, larvae, and terminal damage by sampling 25 terminals in the middle 4 rows/plot. Yields were taken by mechanically harvesting the middle 2 rows/plot on 27 Oct.