Control of Fall Armyworm in Sweet Corn with Bacillus Thumngiensis, 1991

Abstract

Field trials were conducted in fall 1991 in Jonesboro, AR, in sweet corn planted 19 Jul on Calloway silt loam soil. The experimental design was a randomized complete block with 4 replications. Plots were 2 rows wide (1 m row spacing) and 10 m long with 1 row separating adjacent plots. Applications were made on 1, 5 and 8 Aug using a CO2 pressurized backpack sprayer equipped with one hollow cone nozzle situated ca 15 cm directly over the whorl and calibrated to deliver 93 ha-1 at 0.27 MPa. FAW population density and plant damage was determined by dissecting 10 randomly selected plants/plot prior to applications and 4 days following the last application. Larvae were categorized as small (<0.5 cm), medium (>0.5<1 cm), and large (>1 cm). Damage was rated for each plant as: (1) very little to no damage, (2) slight damage to outside leaves and whorl, (3) moderate damage to outside leaves with whorl damage fresh and very apparent, (4) heavy damage throughout plant, and (5) complete decimation. All data were subjected to ANOVA, and means were separated using LSD.