EVALUATION OF SELECTED SEED TREATMENTS AND IN-FURROW INSECTICIDES FOR CONTROL OF THRIPS IN VIRGINIA COTTON, 2005

Abstract

Selected insecticides applied onto seed or into the seed furrow at planting were evaluated for control of thrips in VA cotton. 'Delta Pine 434 RR' cotton was planted 2 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA, using 36-inch row spacing. Cruiser 5FS and Gaucho Grande seed treatments were applied commercially. In-furrow (IF) treatments were applied into the seed furrow at the time of planting using tractormounted inverted jars with lid holes calibrated to deliver exact amounts via gravity. A RCB experimental design was used with four replicates; plots were four rows by 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 to 25% buds injured; 4 = 90% injured leaves, and greater than 25% buds injured; and 5 = dead plants. Yield was determined on 27 Oct by harvesting the 2 center rows of each plot (80 row ft) using a commercial 2-row cotton picker. Sub-samples were ginned to determine lint versus seed and trash weight (40% lint, 60% seed and trash). Data were subjected to ANOVA and means were separated using LSD (P = 0.01).