Forage

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.

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.

Drought-Stressed Forage: Nitrate Considerations

While drought-stressed forages can provide valuable feed, they may also carry an increased risk of nitrate accumulation. Producers should be aware of before grazing, harvesting, and feeding these forages.

High Nitrates and Pregnant Cows

Drought poses many challenges to the beef cow herd. When considering grazing pregnant females, it’s important to understand that grazing management is critical to avoid nitrate toxicity and potential abortions.

Have you observed chemical management failure for alfalfa weevils?

SDSU Extension entomologists are currently looking for alfalfa fields with a past alfalfa weevil insecticide failures. We are collaborating with North Dakota State University and the University of Minnesota on project to determine if pyrethroid resistance exists in our respective states.

South Dakota Grasshopper Prediction for 2026

Almost every year in South Dakota there is a risk that grasshopper populations will reach levels capable of causing issues for producers. Unfortunately, our prediction for the 2026 growing season won’t change the trend.

Drought Conditions Magnifying Impact of Black Grass Bugs

Black grass bugs are a common early-season pest of forage grasses. Drought conditions exacerbate their impact by stressing plants and reducing their ability to tolerate and recover from feeding injury.

Start Management Plans Now: Absinth wormwood, Canada thistle and leafy spurge have emerged and are starting to grow

Absinth wormwood, Canada thistle and leafy spurge have emerged and are growing in eastern South Dakota. If not effectively managed, these weeds can displace desirable forage in pasture and rangeland.