Rangeland Vegetation Response Following Control of Brownspine Pricklypear (Opuntia phaecantha) with Herbicides

Abstract

Brownspine pricklypear (Opuntia phaecantha Engelm. & Bigel.) was effectively controlled within 2 yr following application of a 1:1 mixture of 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] and picloram (4-amino-3,5,6-trichloropicolinic acid) at a rate of 0.6 kg ae/ha. Brownspine pricklypear canopy cover and dry weight declined from approximately 23% and 3800 kg/ha to 8% and 1600 kg/ha, respectively. No significant difference in total herbaceous forage dry weight was found between plants growing inside brownspine pricklypear canopy areas and plants growing outside the canopy areas. Differences between areas in species composition were significant in that cool-season grasses dominated the canopy area of the brownspine pricklypear colonies while warm-season grasses dominated the area outside the canopy. Control of brownspine pricklypear will enhance livestock carrying capacity of rangeland in the Rolling Plains of Texas by increasing forage availability but not forage production.