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Content by Adam Varenhorst

Greenish brown bugs on a white sweep net cloth.

Alfalfa Plant Bugs Showing Up in Abundance

There have been several insect pests showing up in alfalfa this season, including the alfalfa plant bug. We consider the above-average spring temperatures and drought-stressed plants in Eastern South Dakota to be the primary drivers of these issues.

Gray beetle resting on the purple blossom of an alfalfa plant.

Blister Beetles Already Appearing in Alfalfa

Large blister beetles populations were observed while scouting alfalfa this past week. While they usually aren’t an issue until after the first cutting, this early activity means growers should monitor alfalfa fields prior to harvest for the remainder of the season.

Left: Alfalfa weevil larvae. Right: Alfalfa weevil adult.

Alfalfa Weevils Are Active in South Dakota

Alfalfa weevil larvae are active across South Dakota. Although they had a somewhat slower start this year, we are now observing all instars of the larvae in alfalfa fields.

Green leafhopper with clear wings.

Aster Leafhoppers Detected in South Dakota Wheat

Aster leafhoppers are present in wheat again this spring. For the last few years, aster leafhoppers have been a common occurrence in South Dakota wheat.

Green aphid with red eyes and cornicles with black tips.

Large Pea Aphids Detected in South Dakota Alfalfa

Pea aphids are a common pest of alfalfa in South Dakota, and large populations have been detected again in 2026. When large populations are present, their feeding can cause the alfalfa fields to take on a “golden” color.

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.

Dark colored caterpillar with two distinct black lines on head capsule.

Dingy Cutworms Causing Issues in South Dakota Soybean

Dingy cutworms are commonly observed during the spring but typically do not reach major pest status. However, when the conditions are right, they can cause substantial feeding injury to seedling soybeans, as well as corn, wheat, and sunflower.

Drought-stressed cornfield.

Agronomic Considerations During Drought

Despite technological advances, weather factors still play a major role in crop production, especially during dry times. Making smart agronomic decisions can prevent a drought situation from getting worse.

Wheat field that is turning yellow due to mite infestation.

Brown Wheat Mites Detected in South Dakota Wheat

Brown wheat mite infestations have been detected in South Dakota wheat. Typically, infestations are more commonly observed in fields experiencing drought stress, which is currently most of the state

Green wheat plants with some cut just above the soil surface.

Army Cutworms Causing Issues in South Dakota Wheat

Army cutworm caterpillars are active in South Dakota wheat fields. This activity is only going to increase with the forecasted temperatures.