Chemical Control of the Cotton Bollworm and Tobacco Budworm in Cotton, 1984

Abstract

Abstract Cotton was planted 14 May on rows spaced 40 inches apart. The experiment was arranged in a randomized complete block design with 4 replications. Plots were 10 rows wide X 60 ft with 4-ft alleys between blocks. The inner 6 rows of each plot were treated leaving a 4-row buffer between contiguous plots. Insecticides were applied with a high clearance sprayer calibrated to deliver 4 gal of solution per acre through two TX-3 hollow cone nozzles per row at 58 psi and 4 mph. Each insecticide was applied in water and in a 6.25% oil plus water emulsion. Natur’l oil, a blended vegetable oil with emulsifiers, was used for all oil emulsion treatments. Insecticide applications were made 19, 24 and 28 Jul, and 2, 8, 13 and 18 Aug beginning on the 12th day of cotton bloom. Cotton bollworm and tobacco budworm infestation and damage levels were determined the day before and approximately 4 days after an insecticide application, by examining 50 plant terminals per plot to record numbers of larvae and eggs, and by the collection and examination of 50 third grown or larger squares, chosen at random, to determine damage levels. Cotton yields were determined by harvesting cotton from plants in two, 20-ft sections in each plot. Cotton in each plot was harvested twice.