Wheat Weeds

All Wheat Weeds Content

Green plant with bright yellow flowers throughout.

Leafy Spurge: Do I spray now or wait until fall?

In June, leafy spurge is one of our most problematic rangeland, pasture, and roadside weeds. It is also one of South Dakota’s noxious weeds that landowners are required by law to control. So should you spray it now or wait until fall?

Two pictures of two different species of thistle. Both pictures are filled with a green thistle plant and various green plants in the background.

Thistle Species Are Budding in South Dakota

Thistles are starting to bud across South Dakota. This is a critical growth stage for management, as the plants are beginning to produce seeds and herbicides are not effective.

Green perennial sowthistle with yellow flowers at top in the foreground with blurred green, soybean plants in the background.

Perennial Sowthistle Management

Perennial sowthistle inhabits roadsides, pastures, rangelands, and croplands. It can be abundant in overgrazed, over-hayed, or over-mowed areas, as there is little desirable vegetation to compete against the weed.

A black ink pen lain next to small, green and red waterhemp plants with a brown, dirt background.

Waterhemp Has Emerged in South Dakota: Time to prepare for post-emergence management

Waterhemp has started to emerge across South Dakota. While waterhemp plants are small now, recent rain events and forecasted warmer air temperatures are ideal for waterhemp growth.

Green to yellow kochia plants within sixteen, separate black pots filled with brown soil. Green, white, pink and blue marker stakes are within the pots denoting treatments.

Dicamba-Resistant Kochia Can Likely Be Found Across South Dakota

Kochia populations collected across South Dakota have been subjected to an herbicide effectiveness screen, where a treatment of dicamba was applied and some kochia plants exhibited survival and regrowth after treatment.

Two small, green soybean plants with brown to yellow coloration on their leaf edges, indicative of herbicide damage. Tan sand and yellow fertilizer pellets are in the background.

Wind and Rain May Have Delayed Preemergence Herbicide Application: What Now?

With recent winds and rain, preemergence herbicide applications may be further delayed. Scouting to determine if crops and/or weeds have emerged is critical to ensure effective and safe application of preemergence herbicides.

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.

Corn plants and scattered weeds emerge from a dry, no-till field.

Dry Conditions May Hinder the Performance of Recently Applied Preemergence Herbicides

If a preemergence herbicide does not receive an activating rainfall, generally 0.5 to 1 inch of rain, many weeds will emerge, as the herbicide remains on the soil surface.

Ten small green pots with brown dirt and green kochia plants within with a black background.

Saflufenacil-Resistant Kochia Confirmed in South Dakota

Saflufenacil is an herbicide that can be applied at a burndown timing before most South Dakota crops to effectively manage kochia. However, overreliance on saflufenacil has selected for resistant kochia in our region.

Bull thistle, Canada thistle, and absinth wormwood emerging in early spring.

Noxious Weeds Have Germinated in East River South Dakota

Seasonal conditions have been favorable for weed germination, including biennial thistle, Canada thistle, and absinth wormwood. Learn some tips for scouting, identifying, and managing these noxious weeds before they become a problem.