New Herbicide Offers Faster Control of Prickly Pear

After months of rain, ranchers will be turning their attention to brush control.

For prickly pear infestations, Texas and Southwestern ranchers have a new, faster-acting option to control prickly pear and other cacti in "Surmount." The new herbicide from DowAgroSciences LLC provides faster reduction of live prickly pear cover, with comparable final rootkills and cost.

While it’s long been used as emergency livestock feed in far South Texas during severe droughts—and can offer cover to some wildlife—too heavy an infestation of prickly pear takes over, and chokes out desirable plants. In fact, left alone, prickly pear colonies can increase by about 33% per year—or double in less than three years.

Ranchers have long relied on Tordon 22K herbicide, or Grazon P+D, some times in combination with prescribed burns of pastures. While effective, those treatments have been slow. While the standard broadcast treatment is typically applied in the fall, the full effect of Tordon 22K and Grazon P+D on prickly pear may not be realized for three years. Nevertheless, the two herbicides have been the only products recommended for broadcast applications on prickly pear.

In a series of experiments by Dow AgroSciences, the new Surmount herbicide consistently acted faster than current treatments. The faster action of Surmount is due to fluroxypyr, a new active ingredient Surmount brings to cactus control. Surmount combines fluroxypyr with picloram, the active ingredient in Tordon 22K herbicide, and one of the actives in Grazon P+D herbicide.

Agronomist John Breen says in comparisons of the three products, he has seen prickly pear pads turn yellow and melt down quicker with Surmount. It is safe on rangeland grasses, so forage production is not sacrificed. Prickly pear is notoriously slow to die. Even with Surmount, it may take a year or more to cause significant reduction in pear cover, Breen says.

In experiments rated two years after application, Surmount applied at four pints per acre averaged more than 75% control of prickly pear cover. Tordon 22K at its maximum rate of two pints per acre averaged 41% control.