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Corn Insects

All Corn Insects Content

Redlegged, differential, and twostriped grasshopper nymphs.

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.

Green corn leaf with ragged holes through-out caused by common stalk borer feeding.

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.

aerial view of South Dakota farm and surrounding land

Crops

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

Map of South Dakota of Northern Great Plains and the Western United States. Colors indicate the number of grasshoppers per square yard in each of the sampled locations. For a detailed description, please call SDSU Extension at 605-688-4792.

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.

sun rising over South Dakota field

South Dakota Pest Management Guides

The South Dakota Pest Management guides are now available for free. The guides offer recommendations for controlling weeds, insects, and diseases in a variety of South Dakota crops.

Aerial view of the SDSU Southeast Research Farm.
Jan 06

Southeast Research Farm Seminars @ Dakota Farm Show

Join SDSU Extension for a series of educational presentations during the Dakota Farm Show from January 6-7, 2026, at the USD DakotaDome (1101 N Dakota St, Vermillion, SD 57069).

corn field with sunrise in the background

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.

Multicolored Asian lady beetle, female mosquito, and boxelder bug.

Insects Are Being a Nuisance This Fall

The weather is changing, and many of us are noticing an uptick in the nuisance bites caused by several insects. The continued warm weather is going to increase the activity of all insects, including the ones that are causing us displeasure.

Western bean cutworm caterpillar on corn.

Western Bean Cutworms Detected in South Dakota Corn

Western bean cutworm caterpillars have been reported in South Dakota corn. This pest can cause yield loss by feeding on the tassels, silks, and ears. In addition, ear feeding activities increase the likelihood of secondary diseases and mold growth on the ear.

Green plant with evidence of honeydew and an aphid colony.

Aphids Infesting Corn in South Dakota

Aphid populations are taking off in some southeastern South Dakota corn fields. The two aphid species that are commonly observed in corn include the corn leaf aphid and the bird cherry oat aphid.