Evaluating the impact of selective insecticides on pest and beneficial insect populations in Mississippi soybean production

Soybean looper (Chrysodeixis includens) and corn earworm (Helicoverpa zea) are economically significant pests in Mississippi soybean fields. Although naturally occurring predators contribute to pest suppression, outbreaks often necessitate the use of foliar insecticides. Broad-spectrum insecticides, while effective, can disrupt predator communities and trigger secondary pest outbreaks. Recently developed selective insecticides, such as sulfoxaflor (Transform), chlorantraniliprole (Vantacor), and isocycloseram (Plinazolin), offer potential for controlling pests with reduced impact on beneficial insects. However, their effects on predator-prey dynamics remain understudied. To address this, a field experiment will be conducted at the R.R. Foil Plant Science Research Center in Starkville, MS, using three soybean planting dates. The study will include Transform, Vantacor, Plinazolin, Acephate (as a broad-spectrum standard), and an untreated control, arranged in a randomized complete block design with four replications. Pest and predator populations will be sampled via 50 sweep net passes per plot at 4, 7, and 11 days after treatment and identified to species. Enzyme-linked immunosorbent assays (ELISA) will be conducted on dominant predator species to evaluate prey consumption. Results from this study will help guide insecticide selection strategies that preserve beneficial insects while maintaining effective pest control in soybean systems.