EVALUATION OF SELECTED IN-FURROW AND SEED APPLIED INSECTICIDES, WITH AND WITHOUT AN ADDITIONAL FOLIAR BAND OR BROADCAST APPLICATION, FOR CONTROL OF THRIPS ON VIRGINIA COTTON, 2002

Abstract

Selected insecticides applied either onto seed or into the seed furrow at planting, both with and without an additional foliar band or broadcast treatment, were evaluated for control of thrips in Virginia cotton. 'Paymaster 1199 R' cotton was planted 29 Apr at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA, using 36-inch row spacing. In-furrow (IF) treatments were applied into the seed furrow at the time of planting using tractor-mounted inverted jars with lid holes calibrated to deliver exact amounts via gravity. Gaucho 480 seed treatment (seed) was applied commercially. The foliar treatments were applied with a CO2 pressurized backpack sprayer either as a 12 to 14-inch band (FB) over the row at 17.0 gpa and 22 psi through one 8004E flat fan nozzle per row, or as a broadcast (BC) at 14.3 gpa and 18 psi through 8002VS nozzles spaced 18 inch apart on the spray boom. Foliar applications were made on 17 May at the first sign of true leaf emergence after the cotyledon stage and on 29 May at the 2-3 true leaf stage. A randomized complete block experimental design was used with four replicates; plots were 4 rows x 40 ft. Thrips injury to plants was determined by visually rating injury using a 0 to 5 scale, where 0 = no thrips induced plant injury, 1 = 10% injured leaves, no bud injury; 2 = 25% injured leaves, no bud injury; 3 = 75% injured leaves, and 0-25% buds injured; 4 = 90% injured leaves, and > 25% buds injured; and 5 = dead plants.Yield was determined by harvesting the two center rows of each plot (80 row ft) using a commercial 2-row John Deere cotton combine. Sub-samples were ginned to determine lint versus seed and trash weight (40% lint, 60% seed and trash). Data were analyzed using ANOVA and LSD statistical procedures.