The Samuel Roberts Noble Foundation, Inc.   Late-Season Weed, Brush Control Strategies
  Fall not only brings a change in the weather, but also a lot of chores. One management strategy to consider in the fall is the control of several perennial weeds, including field bindweed, Johnsongrass, bermudagrass, Sericea lespedeza and brush. Noble Foundation soil and crops specialist Jeff Ball offers a few best management strategies to control these hard-to-handle weeds.

Field bindweed is a perennial weed that spreads from both roots and seed. Stems can be several feet long and either run along the soil surface or climb on existing plants. Bindweed is an aggressive weed that causes a tremendous amount of yield loss annually in wheat. The best method of control is to apply glyphosate (Roundup or generic equivalent) or LandMaster (glyphosate and 2,4-D) in a timely manner through the summer fallow period. The last application should be applied after planting wheat two weeks before the first killing freeze. Glyphosate is nonselective, and spot treating will kill growing wheat in the infested areas.

"However, it is unlikely you will have much wheat production in the problem spots anyway," Ball adds. "This should be repeated annually to achieve acceptable control."

Other herbicides are labeled for bindweed, but only offer suppression.

Johnsongrass is not native to the United States. It was imported as a forage crop from Europe. In the South, it is a troublesome perennial weed that can cause severe yield loss in both pastureland and row crop production. Johnsongrass spreads from both seed and rhizomes and is good forage, except that, under the right growing conditions, it can be toxic to cattle (both with nitrate accumulation and prussic acid). Control is difficult since it is a grass weed growing in a grass crop. However, in row crop production, there are several herbicides available to control Johnsongrass.

"Pastureland is a different story," Ball says. "We recommend using a weed wiper loaded with glyphosate to control Johnsongrass."

Late fall is a good time to control Johnsongrass as it is accumulating carbohydrates (energy) in the roots prior to winter dormancy. As nutrients move to the roots, so will the herbicide, killing both top growth and roots.

Sericea lespedeza is an introduced perennial legume from eastern Asia. It was touted for its quality forage characteristics for both wildlife and livestock. Though nutritive value is high, palatability is low. Sericea lespedeza's ability to grow no matter the environmental conditions allows it to out-compete more desirable grass species. Mowing and burning will not control Sericea. In fact, Sericea responds favorably to fire and tends to spread after burning. For good control, apply either Cimarron or Cimarron Max anytime through the fall.

"Most think that brush should be controlled by a foliar application in the spring or summer," Ball says. "However, there is an opportunity for brush control in the fall and winter by using a basal bark treatment."

Basal bark is defined as applying a 15 percent to 25 percent Remedy/diesel solution to the trunk of targeted brush species. The application should be made 12 to 15 inches above the soil surface, covering 360 degrees around the trunk. This treatment can be used on oaks, mesquite, locust and even greenbriar.

"Individual plant treatment is labor intensive, but the weather is more favorable in the fall than summer to stomp through your pastures," Ball says.

For questions regarding weed identification or herbicide selection, call a Noble Foundation soil and crops specialist at (580) 224-6500.

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The Samuel Roberts Noble Foundation (www.noble.org), headquartered in Ardmore, Okla., is a nonprofit organization conducting agricultural, forage improvement and plant biology research; providing grants to non-profit charitable, educational and health organizations; and assisting farmers and ranchers through educational and consultative agricultural programs.

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