Control of Bean Leaf Beetle, Banded Cucumber Beetle, and Threecornered Alfalfa Hopper on Soybean in Louisiana, 1990

Abstract

Abstract Four tests were conducted to examine the efficacy of selected insecticides against soybean insect pests. Tests I and II were conducted on Delta Pine 105' soybeans at Hamburg, La. Plots measuring 60 ft (Test I) and 50 ft (Test II) × 8 rows (30 inch row spacing) were arranged in a randomized complete block design with 4 replications. Insecticides were applied with a CO2 pressurized backpack sprayer calibrated to deliver 15 gal/acre at 40 psi through 8002 flat fan nozzles. Treatment occurred on 30 Aug and 1 Sep for Test I and Test II, respectively. Insects were sampled with a 15-inch-diam sweep net at 2 and 5 or 7 DAT. Approximately 0.4 inch of rain fell on 5 Sep. Tests III and IV were conducted on 'Centennial' soybeans at the Macon Ridge Branch, Northeast Research Station, Winnsboro, La. Plots measured 50 ft × 4 rows (40 inch row spacing) and were arranged in a randomized complete block design with 4 replications. Insecticides were applied with a compressed air, tractor mounted sprayer calibrated to deliver 10 gal/acre at 38 psi through X12 hollow cone nozzles. Treatment occurred on 11 Sep and 18 Sep for Test III and Test IV, respectively. Insects were sampled with a 15-inch-diam sweep net at 2 and 6 or 7 DAT. One "beat-net" sample per plot was taken in Test IV at 7 DAT to assess the impact on threecornered alfalfa hopper nymphs. Test III received 0.78 and 0.84 inches of rainfall on 11 and 12 Sep, respectively. Test IV received 0.2 and 0.3 inches rainfall on 19 and 20 Sep, respectively.