Content by Adam Varenhorst

Red-brown colored weevil with bent antennae originating on the elongated mouthparts.

Red Sunflower Seed Weevils in South Dakota

Fact sheet on red sunflower seed weevils in South Dakota

Green alfalfa weevil larvae with a white stripe running down its body.

Alfalfa Weevil Activity Prediction Update: May 29, 2025

The lowest calculated degree days in South Dakota indicate that fourth instar larvae should be active, while the highest calculated degree days suggest that pupation is occurring in the field.

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: 2024-2025

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.

Alfalfa weevil larvae and adult.

Alfalfa Weevils Are Active in Some Parts of South Dakota

Degree day accumulations indicate that alfalfa weevil larvae should be active throughout South Dakota.

Green alfalfa weevil larvae with a white stripe running down its body.

Alfalfa Weevil Activity Prediction Update: May 22, 2025

Degree day accumulations for alfalfa weevil larvae indicate that third to fourth instar larvae should be active in fields throughout South Dakota.

A small black bug with tan margins on its wings resting on a grass seed head.

Black Grass Bug Activity Ramping Up

Black grass bugs feed on fresh green growth, which can result in stunted plants and decreased forage quality. Monitoring and potential management of black grass bugs will be of increased importance this spring, especially if drought persists.

2025 Rangeland Grasshopper Hazard map. Photo Courtesy of USDA APHIS, PPQ. ALT TEXT: 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 2025

In 2025, it is likely that grasshopper populations will once again reach levels capable of causing issues in some areas of the state. Scouting should begin shortly after planting in areas where they were problematic in 2024 and continue throughout the growing season.

Four common South Dakota ticks: American dog, Rocky Mountain wood, blacklegged and Lonestar.

Spring is here, and so are the ticks!

As spring continues to bloom, more arthropods will begin to emerge from winter dormancy. Ticks are among the first to appear, and statewide reports have already been flowing in.

Close-up of a plant with broad, lobed green leaves with serrated edges. The stems and veins of the leaves are a reddish-purple color and possess dark spots.

Identification and management of common cocklebur

Fact sheet to help identify and manage common cocklebur.

Patch of green giant ragweed plants growing among corn plants.

Identification and management of common ragweed and giant ragweed

Fact sheet to help identify and manage common ragweed and giant ragweed.