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Plastic bag containing numerous green larvae.

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.

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.

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.

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

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Although the degree day estimates suggest that alfalfa weevils are no longer active in the fields and should be pupating, scouting has indicated otherwise.

A tall, grassy warm-season cover crop blend grown in South Dakota.

Alternative Forage Options During Dry Times

Although there are many factors to take into consideration, annual forages and cover crops can be an excellent tool to boost forage production, reduce fallow acres, and enhance soil health.

A green leafy spurge plant with small, yellow bracts at top. Various brown and green plants surround the green leafy spurge plant.

Leafy spurge has germinated and is growing rapidly in South Dakota: Scout carefully!

Leafy spurge can reduce the value and productivity of pasture and displace desirable vegetation. Now is the time to scout for infestations to determine which management tactics will be most effective.

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.

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.

A group of producers surveying a grazing area in early spring.

Spring Planting and Grazing Adjustments During Drought

Dry springs mean management changes for both farmers and ranchers as they plan for summer. Learn some important considerations for planting and grazing during a dry spring.