Evaluation of Selected Insecticides and Application Timings for Control of Cereal Leaf Beetle and Aphids on Wheat, 1997

Abstract

Abstract Efficacy of selected insecticides and application timing was evaluated against CLB and aphids in wheat. Pioneer 2580 was planted 8 Nov in a producer’s field in Dinwiddie County, VA, using a 7-inch row spacing. All treatments were broadcast as foliar sprays with water using a CO2 pressurized backpack sprayer calibrated to deliver 20.0 gpa at 30 psi through 8004VS flat fan nozzles spaced 19 inches apart on the spray boom. A RCB experimental design was used with 4 replicates: plots were 17 rows by 50 ft. CLB sampling involved recording the number of eggs and larvae/ft2 (20.57 inches of a 7-inch row). Aphids were sampled by removing 5 randomly selected grain heads per plot. Samples were placed in a mild soapiwater solution (2 drops liquid dish detergent per gal water) for 10 minutes. Samples were then rinsed over a U.S.A. Standard Testing Sieve No. 60 mesh, and the total number of aphids per sample recorded. Defoliation was evaluated by removing 10 randomly selected flag leaves from each plot and visually recording the percent defoliation per leaf. Average percent defoliation was recorded per plot. Treatments 1-5 were applied at Zadok’s growth stage (GS) 31 (3 Apr), treatments 6-10 at Zadok’s growth stage 37 (23 Apr) and treatments 11-15 at Zadok’s growth stage 56 (6 May). Post-treatment CLB egg and larvals samples were taken 3 days after final treatment (9 May). Post-treatment aphid and defoliation samples were taken 24 days after final treatment (24 May).