Green Cloverworm Efficacy Trials

Abstract During 1975, 84 soybean plots were located 5 miles southwest of Ames, Iowa. Each plot measured 50 ft by 4 rows (30-in centers) and was bordered by 2 buffer rows. Experimental design was a randomized complete block, 4 blocks each with 21 treatments. Treatments are given in the table. Treatments were applied on August 6, 1975, with a 4 row CO2 charged bicycle sprayer (liquid output at 40 psi = 29.9 ml/sec). Spray nozzles were Delavan BC 10-70° No.-6. Weather conditions were slightly cloudy, breeze ca 5 mph, temperature ca 70°F. Soybean plants were in maturity stage R4 (pods growing in size). Plots were sampled with a 15 inch diam sweepnet (20 sweeps/plot) on 4 dates: August 5 (pretreatment), August 7 (24-hour post-treatment), August 9 (72 hour post-treatment), and August 13 (7-day post-treatment). Samples were examined for green cloverworm larvae in the laboratory. Plots were examined and rated on August 13 for visual signs of phytotoxicity, viz., leaf discoloration. Rainfall during the sampling period was measurable on August 10, 11, and 12 with a total of 1.03 inches of rain.