Pricklypear Control with Fire and Herbicides on the Texas Rolling Plains
A fire/herbicide system and the efficacy of picloram compared to tricolpyr in this system was evaluated for prickypear control. The study was initiated in 1987 and repeated in 1988, with control for 4 and 3 years post-treatment, respectively. Pricklypear response varied depending on year of application. Fire alone in the 1987 experiment did not provide sufficient control after 4 years. Fire plus picloram at 0.25 lb ai ac-1 provided 89% reduction of pricklypear canopy cover after 4 years. In 1987 unburned plots receiving the 0.25 lb ai ac-1 rate of picloram also provided the best control after 4 years (73% reduction). Fire alone in the 1988 experiment provided substantial control of pricklypear after 3 years (72% reduction). Pricklypear control in 1988 was enhanced by the addition of picloram treatments on burned plots. The addition to triclopyr to burned plots provided little benefit over that of fire alone. In 1987 unburned plots initial canopy cover played an important role in the comparison of pricklypear response to herbicide treatments. Picloram at 0.25 lb ai ac-1 applied to 1987 unburned plots generally provided better control than other treatments, but only when initial canopy cover was above specific amounts.