Corn Insects

Crops

During the growing season, SDSU Extension provides weekly production recommendations.

Corn

Nearly one out of every three dollars generated by South Dakota agriculture starts in a corn field. Two of every three rows of corn become ethanol.

Large Grasshopper Nymph Populations Detected in Southeast South Dakota

This week we received several reports of large grasshopper populations originating from southeast South Dakota. The populations were well above threshold and actively defoliating crops.

European Corn Borer Caterpillars Are Active: Scout your conventional corn

European corn borer caterpillars have been observed in conventional corn at several locations. Indicators for presence of are a line of straight holes in the upper leaves that is often referred to as shot-hole injury.

Various Grasshopper Species Are Active Across South Dakota

While scouting, we have noticed increased grasshopper nymph activity and in some areas these populations are close to threshold levels. Crops in areas that have had high populations should be regularly scouted to ensure that extensive defoliation doesn’t go unnoticed.

Common Stalk Borer Identification and Management

Common stalk borer caterpillars typically only infest the first few rows of corn adjacent to a road-ditch or waterway. However, if weedy alternative hosts are removed early and the caterpillars are left unmanaged, they can reduce stands and leave the end rows looking rough.

South Dakota Grasshopper Prediction for 2026

Almost every year in South Dakota there is a risk that grasshopper populations will reach levels capable of causing issues for producers. Unfortunately, our prediction for the 2026 growing season won’t change the trend.