Soybean Insects

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soybean pods

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
Small shiny fly larvae with black heads on a brown plant root.

Fungus Gnats Affecting Soybean Emergence

We have recently received a report of a maggot attacking soybean seedlings. During most years, we would immediately expect this to be a case of seedcorn maggots, but it was fungus gnat larvae.

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

Soybean Gall Midge Larvae Active in South Dakota

Soybean gall midge larvae are active in soybean in southeastern South Dakota. The first symptoms of an infestation during this part of the season vary based on the size of the population within the plant.

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, a Vector of Bean Pod Mottle Virus, May Be Active in Soybean

Although we are predicting low overwintering survival of bean leaf beetles this year in South Dakota, scouting for this pest should still be conducted, as every year we still observe populations in soybean.

Soybean plants cut by cutworm caterpillars

Keep an Eye Out for Cut Soybean Plants: A Sign of Dingy Cutworm Presence

Dingy cutworms have been observed in South Dakota no-till soybean fields. Their activity will likely continue for at least another couple of weeks.

Green leaf infested by small insects that are brown and black.

Early Season Soybean Infested by False Chinch Bug

At the end of last week, we received several reports of false chinch bugs attacking seedling to early vegetative stage soybean in South Dakota. In these cases very large populations were present on seedling soybeans as well as the ground around them.

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.

A yellow beetle with a black head, and square black markings on its back standing on a soybean leaf.

South Dakota Overwintering Bean Leaf Beetle Predicted Mortality: 2025-2026

Each year we evaluate the overwintering success of bean leaf beetles in South Dakota. For adult bean leaf beetles that successfully overwintered, emergence will begin in the spring and they will move into soybean fields.

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.

A yellowish-orange beetle with black squares along the back resting on a green plant.

Bean Leaf Beetles in South Dakota

This fact sheet provides an overview of the biology of the Bean Leaf Beetle and management options for South Dakota.

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.