Control of Panicle Caterpillars on Sorghum, 1997

Insecticides were evaluated for control of panicle caterpillars at the Texas Agricultural Experiment Station Research Farm near College Station, TX. Panicle caterpillars included corn earworm, fall armyworm, and sorghum web-worm. Seed of hybrid sorghum (ATx399 X RTx430) was planted 16 Jun on rows spaced 30 inches apart. Insecticide treatments were compared in plots, 8 rows X 40 ft long, arranged in a RCB design with 4 replications. Insecticides were applied to the middle 2 rows of plots when sorghum was in the dough stage. Insecticides were applied on 9 Sep between 0930 and 1100 h CDT by using a hand-held backpack sprayer with 4, TX-3 hollow cone nozzles at 35 psi. producing a finished spray volume of 4.9 gpa. Caterpillar abundance was assessed by using the “beat bucket” technique to sample 10 panicles per plot. A pre-treatment count of headworms and webworms was made just prior to insecticide application. Post-treatment counts were made on 10(1 DAT) and 12 Sep (3 DAT). Data were statistically analyzed by using ANOVA and LSD. Percent control was calculated by using the Henderson and Tilton (1955) sampling formula.