Quackgrass (Agropyron repens) Control in Soybeans (Glycine max) with BAS 9052 OH, KK-80, and Ro-13-8895

Abstract

Postemergence applications of BAS 9052 OH {2-[1-(ethoxyimino) butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexene-1-one} and Ro-13-8895 {acetone-O-[d-2-[p-[(α,α,α-trifluoro-p-tolyl-oxy] phenoxy] propionyl]oxime} at 0.3 kg/ha selectively controlled four- to five-leaf-stage quackgrass [Agropyron repens(L.) Beauv. ♯3AGRRE] 75 and 80%, respectively, 105 days after treatment (DAT). KK-80 {4-[4-[4-(trifluoromethyl)phenoxy) phenoxy]-2-pentenoic} at the same rate and stage of growth controlled quackgrass only 45%. None of the herbicides had preemergence activity on quackgrass. All herbicides applied at 0.8 kg/ha controlled two- to three- or four- to five-leaf-stage quackgrass an average of 88%, whereas applications at the six- to seven-leaf stage controlled quackgrass only 27%, 105 DAT. Cultivation alone 1 DAT provided quackgrass control that gave soybean [Glycine max(L.) Merr.] yields equal to any herbicide or herbicide plus cultivation treatment In a greenhouse experiment, BAS 9052 OH killed 50-bud rhizome systems in 1 day, whereas KK-80 and Ro-13-8895 required 14 and 7 days of translocation, respectively, to provide similar control.