Efficacy of selected foliar insecticides against corn earworm in soybean, 2025

Efficacy of Besiege, Brigade, Intrepid Edge, Prevathon, Steward, and Warrior II against CEW in soybean was evaluated in Sussex County, VA, in 2025. Soybean seed ‘Pioneer 56A71E’ were planted on 8 Jun at 160,000 seed/acre; the experiment was conducted during late R4 (full pod) to early R5 (beginning seed) soybean growth stages. Plot size was 8 rows (15-in row centers) by 200-ft long in a 3-replicate RCB design. Foliar insecticide treatments were broadcast on 20 Aug with a CO2-pressurized backpack sprayer calibrated to deliver 14.7 gpa through XR110015-VS nozzles. The non-ionic surfactant ‘Liberate’ (0.25%, v/v) was tank-mixed and applied with all insecticides. CEW larval densities were assessed by taking 2 15-sweep samples per plot (hitting 2 center rows per sweep) with a 15-inch-diameter sweep net at 2 and 7DAT. CEW instars 1-2, 3-4, and 5-6 were counted as small, medium, and large larvae, respectively. Data were analyzed using ANOVA and means separated using Tukey’s Honestly Significant Difference at the 0.05 level of significance. Pre-treatment counts on 20 Aug averaged 1.5 small, 5.5 medium, 2.3 large, and 9.4 total CEW larvae per sample (n = 13). Insecticides with statistically fewer larvae than the untreated check at 2DAT were Steward (small, medium, and total larvae); Intrepid Edge (medium and total larvae); Prevathon (total larvae); Besiege (total larvae); and Warrior (total larvae) (Table 1). By 7DAT, the larval population in the untreated check had decreased, and there were no differences among treatments. Table 1. Means within columns followed by a common letter are not significantly different (Tukey’s HSD, P ≤ 0.05). The non-ionic surfactant Liberate (0.25%, v/v) was tank-mix applied with all treatments except the untreated check. This research was supported in part with funding by the Virginia Soybean Board and by industry gifts of pesticides. None declared.