Evaluation of Pirate 3 SC Against Boll Worm-Tobacco Budworm in Louisiana, 1993

Abstract

Abstract Cotton was planted 2 Jun with plots consisting of 4 rows (40 in centers) × 50 ft. Treatments were arranged in a RCBD and replicated 4 times. Applications were made with a high clearance sprayer calibrated to deliver 6 gal total spray/acre through Teejet X-8 hollow cone nozzles (2/row) at 45 psi. Insecticide treatments were applied on 4, 9, 20, 31 Aug. Methyl parathion 4 EC (0.33 lb [AI]/acre) was applied to all plots on 24 and 28 Aug to reduce boll weevil infestations. Efficacy was determined by examining 50 plant terminals and squares per plot on 6, 13, 23 Aug and 2 Sep for evidence of damage and the presence of bollworm-tobacco budworm larvae. The data reported for bollworm-tobacco budworm and boll weevil damage are a summary of trial means across sample dates. High numbers of soybean looper and beet armyworm larvae were observed in the plots during Sep and visual defoliation ratings were estimated to evaluate differences among treatments. Each plot was scored as follows: 0 (no feeding damage), 1 (feeding damage within the lower Vi of the plant), 2 (feeding damage in the lower Vi and middle Vi of the plant) or 3 (feeding damage throughout the plant). The plots were mechanically harvested on 17 and 24 Oct to estimate seed cotton yields. The test area received 2.0 inches rainfall on 6 Aug, 0.5 inch on 20 Aug, and 0.3 inch on 28 Aug. Supplemental moisture was provided by sprinkler irrigation "as needed" during the season but not within 48 h of treatment applications.