Control of invasive brush on southwestern U.S. rangelands is a continual struggle. Industry-standard herbicide treatments typically knock brushy weeds back, but not out. That means they can rebound over time and encroach on valuable grazing lands.

Now, though, researchers writing in the journal Weed Technology point to a longer-lasting solution. Multiyear trials conducted in Texas rangelands explored the control of the brushy weeds honey mesquite and huisache. Current industry-standard herbicide treatments (2,4-D and 2,4,5-T) were compared with the results produced by an experimental mixture of aminocyclopyrachlor + triclopyr (ACP+T).

On average, the industry-standard treatments controlled huisache for three years before the weed had rebounded enough to compete again with native forage grasses – requiring a second treatment. The same industry-standard treatments were able to control honey mesquite for more than eight years.

By comparison, ACP+T treatments produced a significantly longer-lasting benefit by killing more brushy weeds. A 12-year analysis of huisache control and a 20-year analysis of honey mesquite control showed a second treatment wasn’t yet required. That means improved forage diversity, lower costs for rangeland managers and less herbicide load in the environment.

Want to know more? You can find the article “Treatment Life and Economic Comparisons of Honey Mesquite (Prosopis glandulosa) and Huisache (Vachellia farnesiana) Herbicide Programs in Rangeland”  in Weed Technology vol. 33 issue 6.