Insect & Pests
All Insect & Pests Content
Scout Corn for Black Cutworm Activity
Black cutworms are a migratory moth that moves into South Dakota during early spring. Although black cutworm caterpillars cause minor corn injury by feeding on leaf tissue, serious injury occurs when feeding results in the cutting of young corn plants.
Alfalfa Weevil Populations Rapidly Increasing in Western South Dakota and Starting to Show up in Eastern South Dakota This Week
Recent degree day accumulations for alfalfa weevils in western South Dakota would suggest that alfalfa weevil larvae activity should be wrapping up for the 2025 season. However, recent scouting of alfalfa suggests otherwise.
Common Stalk Borer Activity Estimate: May 29, 2025
Based on degree day estimates for common stalk borer caterpillar activity, no scouting in corn fields is necessary at this time.
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.
Red Sunflower Seed Weevils in South Dakota
Fact sheet on red sunflower seed weevils in South Dakota
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 Weevils Are Active in Some Parts of South Dakota
Degree day accumulations indicate that alfalfa weevil larvae should be active throughout South Dakota.
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.
Alfalfa Weevil Activity Prediction Update: June 5, 2024
Although the degree day estimates suggest that alfalfa weevils are no longer active in the fields and should be pupating, scouting has indicated otherwise.
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.