Evaluating the impact of biocontrol with entomopathogenic nematodes on non-target arthropods in Texas cornfields

Corn rootworms, including western (Diabrotica virgifera virgifera) and Mexican (D. v. zeae) corn rootworm are major pests of corn, and various control measures, from cultural to chemical, have been used. However, corn rootworms have evolved resistance to all known control methods, including insecticides, cultural control, and Bt corn hybrids. With this growing concern, developing new control methods is important. Biological control with entomopathogenic nematodes (EPNs) offers a promising and more sustainable alternative that may be incorporated as part of an integrated pest management plan. Persistent EPN strains have been developed to control corn rootworm populations and are now sold commercially. Efforts have focused on the efficacy of these strains for pest control, but no studies have evaluated the potential non-target effects on invertebrates present in corn. The long-term goal of this project is to mitigate potential negative effects and better understand the benefits of using persistent EPN strains for biocontrol. The objective of this study was to evaluate potential non-target effects of persistent EPN strains applied for corn rootworm control in Texas, focusing on ground-dwelling arthropods, native nematode species, and lepidopteran pests. We hypothesized that additions of persistent EPN strains would reduce the abundance of select ground-dwelling invertebrates and non-target lepidopteran pests. This will be addressed by applying a mixture of persistent EPN strains (Heterorhabditis bacteriophora + Steinernema feltiae) to a continuous corn system, and monitoring selected beneficial and pest taxa. This study will fill the knowledge gap on the ecological impacts of persistent EPN strains in corn agroecosystems.