Which soybean insects cause the biggest losses depends heavily on where growers farm—one of the clearest takeaways from a recent nationwide pest impact report issued by the Crop Protection Network, a consortium tied to land-grant universities.
Using data from 19 states, the study ranked stinkbugs as the most damaging pest in 2024, with an estimated 12.6 million bushels in yield losses. They led a national lineup that also included corn earworms, soybean loopers, grasshoppers, slugs and bean leaf beetles, showing how multiple pests—rather than a single dominant threat—chip away at productivity.
The regional breakdown underscored just how different the pest landscape is across the country. In the South, stinkbugs dominated, followed by corn earworms, soybean loopers, bean leaf beetles and three-cornered alfalfa hoppers. In the Great Lakes region, particularly Ohio and Michigan, slugs were the most damaging pest, ahead of stinkbugs and seed corn maggots, with Japanese beetles and bean leaf beetles also prominent. In western reporting states such as Illinois, Iowa, Missouri and South Dakota, grasshoppers led the list, followed by bean leaf beetles, stinkbugs, soybean aphids and Dectes stem borers.
Industry experts say the rankings reflect a combination of local climate, cropping systems and economic conditions. Pest pressure, they note, fluctuates year to year. In Illinois, for example, 2025 insect activity was described as relatively light, and analysts expect fewer automatic insecticide applications ahead due to softer commodity prices.
Southern states contributed the bulk of national stinkbug losses, partly because pest intensity runs higher there despite the larger soybean acreage in the Midwest. Bean leaf beetles, meanwhile, scored high nationally because they inflict damage both in southern growing zones and across large swaths of Midwestern farmland—small yield losses over millions of acres add up to major impacts.
The survey also offered insight into why slugs stand out in Midwestern rankings: they cause significant stand loss, and control options are limited, often forcing costly replanting. Slug issues are concentrated in no-till regions stretching from Illinois to Pennsylvania, where conditions frequently favor their survival.
Other pests remain regionally relevant. Corn earworms tend to inflict heavier damage in southern fields, especially when earlier generations move off corn and target soybeans during early pod development. Upper Midwest growers periodically contend with soybean aphids, while Nebraska farmers increasingly factor in soybean gall midge.
Researchers say the greatest value of the survey lies in long-term comparison. Tracking shifting pressures helps extension specialists, commodity groups and agribusiness refine priorities and research programs. While growers may not see their personal ranking reflected in the report, they benefit as trends guide new solutions, funding and pest management strategies over time.
