Evaluation of Insecticide Combinations Against Late Season Populations of Bollworms, Tobacco Budworms and Boll Weevils, 1994

Six insecticide treatments were evaluated at the Macon Ridge Branch of the Northeast Research Station, Winnsboro, LA, to determine their efficacy in controlling the bollworm/tobacco budworm complex and boll weevils. Cotton was planted 18 Jun in plots consisting of 4 rows (40 inch centers) × 50 ft. Treatments were arranged in a RCBD with 4 replications. Treatments were applied with a high clearance sprayer calibrated to deliver 6 gal total spray/acre through Teejet X-8 hollow cone nozzles (2/row) at 46 psi. Insecticides were applied on 22, 26 Aug and 1 Sep against established populations of bollworms, tobacco budworms (primarily tobacco budworms) and boll weevils. Efficacy of the various treatments against these species was determined on 25, 31 Aug and 7 Sep by examining 50 squares/plot for evidence of feeding damage. Also numbers of larvae per 50 squares were recorded for the bollworm/tobacco budworm complex. The plots were mechanically harvested on 25 Oct to determine seed cotton yields. The test area received 0.57 and 0.20 inches rainfall on 1 and 6 Sep, respectively.