Aerial Application of Sevin 4-Oil Efficacy Trials, 1976

Four soybean plots (Var. Amsoy) were located 3 miles southwest of Ames, Iowa. Each plot measured 300 ft by 135 ft (54 rows) with 30 in centers. Experimental design consisted of each plot being randomly assigned a treatment. Treatments are given in the table. Treatments were applied on August 17 by airplane as follows: Sevin 4 - Oil , airplane with 6 Delavan nozzles (equivalent to Tee Jet 8002), spray pressure 40 psi and application rate at 1 qt/acre; Sevin 80S, airplane with 16 Tee Jet No. 6 D-6 nozzles, spray pressure at 30 psi and application rate at 2 qt/acre. Weather conditions on the day of application were: temperature ca 70° F, wind speed ca 8 mph. Plants were randomly sampled with a 15-in diam sweep-net (50 sweeps/row, 4 rows/plot) on August 17 (pretreatment), August 18 (1-day post-treatment), August 20 (3-day post-treatment) and August 24 (7-day post-treatment). Soybeans were in growth stage R5 (beans growing in size) on all sampling dates. Samples were examined for green cloverworm larvae in the laboratory. Plants were examined for visual signs of phytotoxicity, viz., discoloration of leaves, on August 24. No measurable rainfall occurred during sampling.