Content by Adam Varenhorst

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.

Aphid Populations Detected in Wheat

Aphids are present in South Dakota wheat fields, and that means it’s time to start scouting.

Pea Aphid Alert: Forecasted temperatures could result in rapid population increases

The temperatures during the last week and the forecasted temperatures for next week will potentially encourage rapid pea aphid population growth. Although many fields have been cut recently, pea aphids can still readily recolonize alfalfa.

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.

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.

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.

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.

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.

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.

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.