Corn Insects

All Corn Insects Content

Dark green and tan curled caterpillars with an orange stripe along their sides.

True Armyworm Caterpillars Found in South Dakota

Although true armyworms can feed on numerous crops, they are primarily an issue for corn and wheat. True armyworm caterpillars feed on leaves and can cause severe defoliation when large populations are present.

Numerous nymph grasshoppers feeding on corn.

Large Grasshopper Populations Detected in South Dakota

Very large populations of grasshoppers have been detected in southeastern South Dakota. Although these grasshoppers aren’t causing serious defoliation in crops yet, there is the possibility that they will as the season progresses.

Purple-brown caterpillar with orange head on a green corn leaf.

Common Stalk Borer Activity Estimate: May 25, 2023

Common stalk borer caterpillars are a frequent early-season pest of corn, and their hatching and movement can be estimated by using degree days. See our latest scouting and management recommendations based on observations from around the state.

Tan grasshopper with light colored stripes on its back sitting on the soil surface.

South Dakota Grasshopper Prediction for 2023

Grasshoppers can cause serious defoliation in forage, soybeans and corn throughout much of the growing season. See our activity predictions for the 2023 growing season based on the 2022 U.S. Department of Agriculture Adult Grasshopper Survey.

corn field with sunrise in the background

Best Management Practices for Corn Production

iGrow Corn is your unbiased, research-based guide to corn production, providing the latest recommendations to help increase yield, reduce input costs and protect your investment.

An empty grain bin full-air floor is plugged by insect webbing.

Stored Grain Pests: Spring Insect and Disease Issues

Grain storage is a key component in getting your crop to market. Aside from watching bins for spoilage, moisture, and temperature changes, make sure you are looking for signs of pest infestation.

Three grain bins on the edge of a snow-covered field.

Forecasted Cold Temperatures Can Be Used To Cool Down Stored Grain

If temperatures are forecasted as being well below freezing, it would probably be a good time to start thinking about cooling stored grain. Cooling grain reduces the activity of stored grain insect pests and suppresses any mold growth that may otherwise occur.

Brown moth with light markings present on a green leaf.

Western Bean Cutworm Moths Observed in South Dakota

Over the weekend, South Dakota experienced strong southerly winds, which brought warm temperatures to the state. In addition, these winds also brought insect pests north, which included moths of the western bean cutworm.

A pasture containing a mixture of grasses and alfalfa.

Start Scouting for Grasshopper Activity in Crops and Grasslands

Most of Eastern South Dakota is experiencing very low grasshopper populations. However, this is not the case for many areas in Central and Western South Dakota.

Rows of empty white, plastic pesticide containers.

Chlorpyrifos Tolerances Revoked by U.S. Evironmental Protection Agency

In August 2021, a final rule was released by the U.S. Environmental Protection Agency for the insecticide active ingredient chlorpyrifos. The rule revoked all tolerances for chlorpyrifos.