Impact of Solenopsis invicta Buren Suppression on Arthropod Ground Predators and Pest Species in Soybean

The red imported fire ant, Solenopsis invicta Buren, reportedly contributes to the biological control of key soybean pests. However, S. invicta may negatively affect ground-dwelling natural enemies such as ground beetles and earwigs. Information on the interactions between natural enemies is important for anticipating the success of biological control in agroecosystems with multiple interacting entomophagous species. Ground arthropods were monitored in soybean using pitfall traps in the 2000 and 2001 growing seasons to determine their response to selected fire ant controls. Three treatments were examined: an untreated check, Amdro™ (hydramethylnon) bait (ant-specific), and Lorsban™ (chlorpyriphos) (broad spectrum) plus Amdro. Fire ant captures in pitfall traps were lower in the Amdro and in the Amdro plus Lorsban treatments compared to the untreated control. Reduced fire ant density plus chemical treatment impacted the abundance of certain ground predators. Spiders, primarily Lycosidae, were significantly...