Chemical Control of the Cotton Bollworm and Tobacco Budworm, 1982

Abstract ‘Stoneville 213’ was planted in a Tuttle silt clay loam on Jun 12 at the South Central Research Station, Chickasha, OK, at 18 lb of seed/acre. Test 1 consisted of 8 row plots, 150 ft long, replicated 3 times in a randomized complete block design. Test 2 was identical to test 1 except plots were 200 ft long. Spray applications were made with a John Deere Hi-Cycle 6000 sprayer traveling at a speed of 4.5 mph at 40 psi. The John Deere spraying unit was replaced with a Marco system equipped with a roller pump powered by a 3 hp Briggs and Stratton gasoline engine. Insecticide applications consisted of 5 gal total spray mixture per acre, with 1 no 8 hollow cone nozzle (Spraying systems) per row. Applications were made on Aug 10, 17, 23 and 31 for test 1 (except for CME-13401) and Aug 9-10, 16, 24, 30 and Sep 7 for test 2. Intervals between applications ranged from 6 to 8 days. Plots were irrigated with approximately 1 in of water on Aug 14, 18 and Sep 2. The only rainfall recorded during the treatment period was 0.86 in on Aug 28. Damage was estimated by collecting at random 100 fruits prior to spraying from the upper 1/3 of the plants in each plot. Heliothis spp. populations were light throughout the study except for the first application. On Aug 9, prior to the first application 100 terminals were examined at random in test 1 and 2. Seven 1st and 2nd instar larvae were found along with 60 eggs. Heliothis spp. populations were approximately 50% budworm and 50% bollworm during the treatment period.