Low Rates of Tebuthiuron for Control of Sand Shinnery Oak

Abstract

Tebuthiuron [N-(5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl)-N,N′-dimethylurea] pellets (20% ai) were broadcast at 0.2 kg increments to 1.0 kg/ha onto a sand shinnery oak (Quercus havardii) community in west Texas (33 degrees 23′52″N and 102 degrees 46′38″W). Treatments greater than or equal to 0.4 kg/ha reduced oak canopy 98% and standing crop at least 90%. Grass yield was unaffected by herbicide treatments during the first year. Thereafter, yield on treated areas increased from 420 to 690 kg/ha as contrasted to 140 kg/ha on the control. Where oak was untreated, grasses became quiescent, due to drought, up to 6 weeks earlier than on treated areas.