Weed Control and Forage Quality in Tebuthiuron Treated Pastures

Abstract

Control of natural infestations of dogfennel [Eupatorium capillifolium(Lam.) Small # EUPCP] and woolly croton (Croton capitatusMichx. # CYNCP) in a bermudagrass [Cynodon dactylon(L.) Pers. # CYNDA] – dallisgrass (Paspalum dilitatumPoir. # PASDI) sward ranged from 20 to 100% with surface-applied tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N-dimethylurea}. In general, efficacy increased with rate of application from 0.6 to 1.1 kg ai/ha, and with time to 107 days after treatment. Only 0.6 kg ai/ha controlled less than 90% of the weeds during the growing season. Dry matter yields of desirable forage ranged from 60 to 290 kg/ha more with tebuthiuron treatment than in the untreated check. There were no consistent differences in forage quality among treatments, which indicates that tebuthiuron had no detrimental effects upon the bermudagrass or dallisgrass.