Investigation of reduced agent and area treatments for soybean aphid management and its effects on key predators

Soybeans are an abundant and valued agricultural crop in Nebraska and other parts of the Midwest. Significant soybean aphid, Aphis glycines Matsumara, mortality has been observed in research plots adjacent to soybean treated with chlorpyrifos in late July through August. The objectives of our study were to determine the efficacy of the chlorpyrifos vapor effect on soybean aphids in adjacent untreated areas and assess the impact of the vapor effect on key biological control agents. Observation of soybean aphids populations and sweeps of other arthropod species, including Oruis insidiosus, began weekly in early to mid July. When aphid levels reached economic thresholds, chlorpyrifos pesticide was applied to a spray area. Weekly assessments continued to monitor populations both in the spray area and at set distances from the spray area. Results will be presented.