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Content by Philip Rozeboom

Wheat plants infected with wheat streak mosaic virus.

Volunteer Wheat and Kochia Management With Herbicides Will Likely Require Two Passes

Wheat curl mites, which carry wheat streak mosaic virus, use volunteer wheat and grass weeds as secondary hosts to infest recently planted winter wheat crops. Therefore, effective management of these plants before winter wheat planting is critical.

A soybean leaf infested with numerous soybean aphids.

Soybean Aphids Exceeding Thresholds in Some Parts of South Dakota

There have been a few fields this week that were infested with soybean aphids that are getting closer to threshold. We have also received reports of insecticides being applied to manage soybean aphids in South Dakota.

Combine harvesting wheat.

Weed Management After Wheat Harvest

Most of the winter wheat has been harvested in South Dakota and spring wheat harvest is underway. While the growing season is over for the wheat, post-harvest weed management is important to minimize the amount of weeds that are present in the spring

Green Canada thistle with whitened leaves at the top. Various green plants throughout.

White Thistle Disease: Biological management at work

White thistle disease can be seen among many Canada thistle plants throughout South Dakota this growing season. Plants infected with the disease exhibit significant reductions in both growth and seed head compared with non-infected plants.

True armyworm caterpillar on a corn leaf.

Reports of Pyrethroid Failures for True Armyworm Caterpillar Management

True armyworm caterpillars reached thresholds in oats and wheat in many areas of South Dakota recently. Management efforts to reduce populations had varying levels of success, with SDSU Extension receiving numerous reports of pyrethroid insecticide failures.

A picture of a green, smooth crabgrass plant with a white background.

Late-Season Crabgrass Control

At the start of August, crabgrass is often prevalent in lawns. Ideally, this weed should be controlled earlier in the season, but if early management was missed, a post-emergence herbicide can help control it before it produces more seed.

Gray beetle on a green alfalfa plant with purple flowers.

Watch for Blister Beetles in Later Alfalfa Cuttings

The frequent rain events experienced this summer has helped boost forage production. Although this is great for growers, the possibility of encountering blister beetles at harvest increases later in the summer.

Two pictures of green soybeans with a blue sky in the background.

Strong, Effective Herbicide Programs Can Be Complimented With Narrow Row Spacing

While strong herbicide programs will result in effective weed management, a cultural tactic, such as row spacing can result in a complementary increase in effectiveness.

Three bean leaf beetles. From Left: Brown beetle with black spots on a green leaf. Yellow beetle with black spots on a green leaf. Red beetle with black spots on a green leaf.

Bean Leaf Beetles Showing Up in Soybean

Despite the prediction of low overwintering survival we have observed bean leaf beetles in soybean this week. See our latest observations and management recommendations.

United States Environmental Protection Agency Sign plate outside the agency’s main office.

EPA Proposes a Decision to Approve Registration for Dicamba Labeling to Be Applied to Tolerant Soybean

Dicamba products previously labeled for overtop application to tolerant soybean are not registered for use during the 2025 growing season. However, the EPA has proposed to re-register these dicamba products for use in tolerant soybean starting in 2026.