NORTH PLATTE, Neb. — Was cheatgrass, sometimes called downy brome, or wild oats abundant in your pastures this spring? Although difficult, they can be controlled and your pasture revitalized.
Winter annual bromes often invade thin or overgrazed pastures in fall and early spring. Livestock dislike grazing them after they become mature and over time they can take over and make large patches in a pasture.
Recent research by the University of Nebraska evaluated herbicides for controlling cheatgrass. Products containing rimsulfuron and imazapic (Plateau®) can provide good control of cheatgrass from a single application, but control can vary widely from year to year depending on when the application is made, maturity of cheatgrass plants, and the weather patterns. A one-time management operation, utilizing grazing, mowing, or a non-residual herbicide, like rimsulfuron or imazapic, usually does not have a lasting impact on the cheatgrass in the seedbank. To reduce the seedbank, control needs to be close to 100%, and repeated over several years.
Rejuvra™ is a new rangeland herbicide product from Bayer that works differently from existing cheatgrass herbicides. Rejuvra™ has limited activity on emerged plants and only controls seedlings as they germinate, so it is best to apply Rejuvra™ in early fall before seeds germinate. This herbicide can provide control up to two years post application.
In warm-season grass pastures and rangeland, there is another option. You can use glyphosate herbicides after top growth of these grasses has died due to a hard freeze or two. This can kill emerged annual brome seedlings without harming the desirable grasses. However, do not use glyphosate in cool-season pastures because it will injure or kill the pasture grasses as well. With any herbicide, always read and follow label directions.
With these herbicide options and proper grazing management, your pastures can develop thicker stands of the more desirable grasses. It takes a long, dedicated process to recover pastures overtaken by winter annual bromes.
— Jerry Volesky, Nebraska Extension
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