Preventative insecticides reduce seedling injury, but do not increase yield in Bt and non-Bt corn grown in the...

Field corn production systems rely on preventative insect management tactics, including hybrids expressing plant-incorporated protectants that are treated with neonicotinoid seed treatments and sometimes in-furrow pyrethroids. While effective seedling pest control can be crucial because of the cost of replanting, these treatments target many of the same pests and may add unnecessary costs for growers. Furthermore, seedling pests in the Mid-Atlantic tend to be sporadic, and preventative insecticides may negatively impact natural enemies. To better understand the value of common preventative tactics, we evaluated pest pressure and compared a neonicotinoid seed treatment (clothianidin) and an in-furrow pyrethroid (bifenthrin) in Bacillus thuringiensis (Bt) and non-Bt corn hybrids.

In Bt hybrids, the in-furrow pyrethroid did not decrease pest injury, increase stand, or increase yield, while the neonicotinoid seed treatment decreased pest injury and increased stand but did not increase yield. In a non-Bt hybrid, both insecticides decreased pest injury, but neither increased stand or yield. Above- and below-ground pest injury was scarce throughout the study, but even in the site-year with the most extensive injury, insecticides did not result in yield gains.

Implementing efficient economically and environmentally sustainable corn pest management requires a thorough understanding of the contributions of each component of the pest control system. By thoroughly exploring pest pressure in Bt and non-Bt systems, this study shows that preventative insecticide use could be scaled back in many cases, especially given the environmental and economic costs associated with them. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.