Selected Insecticides for Control of Corn Earworm and Green Cloverworm in Soybean in Virginia, 1997

Efficacy of selected insecticides was evaluated against CEW and GCW in soybean. ‘Hutcheson’ soybean was planted 15 June in a producer’s field in Greensville County, VA, using an 18-inch row spacing. All treatments were broadcast as foliar sprays with water on 27 August using a CO2 pressurized backpack sprayer calibrated to deliver 14.3 gpa at 18 psi through 8002VS flat fan nozzles spaced 18 inches apart on the spray boom. A RCB experimental design was used with 4 replicates; plots were 4 rows by 50 ft. Insect samples were taken using a 15-cm diameter sweep net, 15 sweeps per plot. Pre-treatment insect populations were assessed just prior to treatment application by taking several 15-sweep samples throughout the planned test area. Post-treatment samples were taken 2, 4, 8, 12, and 21 days after treatment (DAT) by comparing numbers of small (1st and 2nd instars), medium (3rd and 4th instars), large (5th and 6th instars) and total CEW larvae, and total (all sizes) GCW larvae. Data were analyzing using ANOVA and LSD statistical procedures.