Rotations of Bacillus Thuringiensis and Esfenvalerate for Control of Cabbage Looper in Fall Cabbage, 1991

Cabbage transplants were set 14 Aug in a Calloway silt loam on the ASU Research Farm on single row raised beds spaced 6.6 ft apart with plant spacing at 15 inches. Plots were 1 row, 20 feet long arranged in a randomized complete block with 4 replications. A C02 pressurized backpack sprayer fitted with 2 hollow cone nozzles spaced 20 inches apart and directed at a 45° angle toward the center of the plant was used to apply insecticides at 40 psi in a volume equivalent to 20 gal/acre. Insecticide applications were made 26, 30 Aug, 2, 6, 9, 13, 15, and 20 Sep and evaluated 9 and 24 Sep. Evaluations were made by sampling 5 randomly selected plants per plot. No. of neonate, small, medium, and large larvae, and no. of damaged lower, middle, and head leaves (including 3 wrapper leaves) per plant were determined. In addition, insect damage was rated on a 1 to 5 scale with 1 = no damage, 2 = slight damage (<50% of lower and middle leaves affected), 3 = moderate damage (>50% of lower and middle leaves affected), 4 = heavy damage (unmarketable head with <50% all leaves affected), and 5 = severe damage (unmarketable head with >50% of all leaves affected and >25% loss of leaf area). On 18 Oct determinations of % unmarketable heads attributable to insect damage were made. All data including log transformations of insect counts were subject to ANOVA.