Performance of Selected Insecticides Against Soybean Looper in Soybean 3, 2021

The performance of selected foliar insecticides treatments against soybean looper infestations in soybean was evaluated at the Delta Research and Extension Center (Washington County). Soybean seed (Asgrow 46X6) were planted on a Bosket very fine sandy loam soil on 6 Jul at a seeding rate of 117,612 seeds/acre. Plot size was four rows (40 in centers) by 40 ft. Treatments were replicated four times in a RCB design. Foliar insecticide treatments were applied on 25 Aug with a high-clearance sprayer with a compressed air spray system calibrated to deliver 10 gpa through TX-12 hollow cone nozzles (2/row) at 5 mph. Soybean looper densities were determined by sampling one of the center two rows with a 15-inch diameter sweep net. A sample consisted of 25 sweeps per plot. Plots were sampled at 2, 5, 7, and 14 days after treatment (DAT). The same row in each plot was not sampled on consecutive sample dates. Data were subjected to ANOVA and means separated according to Fisher’s Protected Least Significant Difference.

All of the insecticides reduced looper densities compared to the untreated check at 2, 5, and 7 DAT, except Besiege at 7 DAT (Table 1). Also at 2 DAT, plots treated with Intrepid Edge (6 oz) had fewer loopers than plots treated with Intrepid Edge (5 oz), Prevathon, or Besiege. At 5 DAT, plots treated with Intrepid Edge (4 or 6 oz) had fewer loopers than plots treated with Intrepid Edge (5 oz) or Besiege. No differences among treatments were observed at 14 DAT.¹

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