Insects
Insect pests may cause direct and or indirect injury to crops. Get more information on key insect pests in Iowa, how to scout for them, and how to implement integrated pest management tactics that utilize economic thresholds to know when action is warranted and minimize the spread of insecticide resistance.
Timely Insights on Insects
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April 15, 2026Content Author
Black cutworm (Agrotis ipsilon) is an occasional pest of corn and soybean in Iowa. This insect cannot overwinter here, so spring storms deliver moths to Iowa each year. Because they are migratory, their occurrence in the state is sporadic, and scouting is essential to determine whether fields require treatment for black cutworm larvae. Trapping for moths is a relatively simple way to understand which regions may be at higher risk and predict when larvae may be active in fields.
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April 6, 2026Content Author
Before making pesticide applications this spring, make sure to check areas near fields to prevent off-target pesticide exposure. Herbicide labels often require applicators to consult a sensitive crop registry to identify nearby non-target plants, beehives, or organic farms before application. For example, the dicamba products Engenia, Stryax and Tavium require documentation that the sensitive crop registry was checked.
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March 26, 2026Authors
Seedcorn maggots feed on germinating seeds or seedlings of both corn and soybean (Photo 1). Feeding can slow development or kill the plant, and plant injury is more prevalent during cool, wet springs when plants grow slowly. With planting right around the corner, we recommend that farmers track growing degree days, plant during the fly-free period, and avoid planting into cool, wet soils, especially in fields at high risk for injury. High-risk fields include those with a history of seedcorn maggot injury, recently tilled fields, and fields where organic matter was recently incorporated (e.g., manure or cover crops).
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March 26, 2026Authors
Warm temperatures early in 2026 have accelerated alfalfa weevil development in Iowa. Adults have already emerged from their overwintering sites to lay eggs in alfalfa stems throughout the southern half of Iowa.
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March 11, 2026Content Author
Pesticide labels are changing to better protect endangered species. This means applicators will want to carefully review pesticide labels for substantial changes this year and into the future. For more on the background of these label changes, check out the Herbicides and The Endangered Species Act page from the Weed Science Society of American or this article on the Endangered Species Act written by Bill Chism, a retired senior biologist with the EPA.
