Soybean Insects

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Best Management Practices for Soybean Production

This is your unbiased, research-based guide to soybean production to help increase yield, reduce input costs and protect your investment.

All Soybean Insects Content

Three bean leaf beetles. From Left: Brown beetle with black spots on a green leaf. Yellow beetle with black spots on a green leaf. Red beetle with black spots on a green leaf.

Bean Leaf Beetles Showing Up in Soybean

Despite the prediction of low overwintering survival we have observed bean leaf beetles in soybean this week. See our latest observations and management recommendations.

U.S. Environmental Protection Agency offices in Washington, D.C.

Update on Chlorpyrifos Use in South Dakota

As of June 30, 2025, the labeled uses for chlorpyrifos products for food and feed are limited to alfalfa, soybean, and wheat in South Dakota. Chlorpyrifos can no longer be used to treat sunflowers.

Small, green teardrop shaped insects on a green, soybean stem with pink flower.

Soybean Aphids Detected in South Dakota

While scouting soybean aphids this week we observed small colonies of 5 to 10 soybean aphid nymphs. This indicates that the soybean aphids are just starting to arrive in South Dakota soybeans and weekly scouting for them should be occurring.

Top: Green cloverworm caterpillar. Bottom: Cabbage looper caterpillar.

Green Caterpillars Causing Defoliation in Soybean

This week we observed several species of caterpillars in soybean fields. The most common species were the green cloverworm and the cabbage looper.

Cream colored larvae on white and green soybean stem on brown dirt.

Dectes Stem Borer Adults Are Active in Soybean: 2025 Management Recommendations

Dectes stem borer adults have been collected from soybean in Southeastern South Dakota. The larvae of this pest are capable of reducing soybean yields by 10-15% due to tunneling activity in the main stem. Learn some tips for scouting and managing them this season.

Base of soybean stem with orange larvae present under the epidermis.

Soybean Gall Midge Larvae Detected in South Dakota

Soybean gall midge larvae have been detected in soybean in southeastern South Dakota. Scouting for fields with infestations may explain wilting or dying soybean along field edges.

Gray beetle with long antennae.

Dectes Stem Borer in South Dakota Soybeans

Fact sheet on Dectes stem borer in South Dakota soybeans

Redlegged and differential grasshopper nymphs.

Grasshoppers Are Showing up in Large Numbers in Eastern South Dakota

While scouting spring wheat in Brookings County this week, we noticed grasshopper nymph populations that were close to threshold.

Grasshopper with red hind tibia. It’s sitting on a green grass stem.

Survey of Grasshoppers in South Dakota

Fact sheet on the abundance and species diversity of grasshoppers in South Dakota

Gray beetle with long antennae.

Dectes Stem Borer in Soybean Survey: 2023 and 2024 Results

During the 2023 and 2024 growing seasons, researchers at SDSU surveyed soybean in Eastern South Dakota for the presence of Dectes stem borer adults.