Response of Selected Grass Weeds to Metriflufen

Field evaluations for control of grass species were conducted with metriflufen, the methyl ester of {2-[4-(4-trifluoromethylphenoxy)phenoxy] propanoic acid}, applied as preemergence and postemergence treatments. The preemergence application of 0.28 kg/ha gave 84 to 100% control of all species except grain sorghum [ Sorghum bicolor (L.) Moench], johnsongrass [ Sorghum halepense (L.) Pers.], red rice ( Oryza sativa L.), and green foxtail [ Setaria viridis (L.) Beauv.]. These species required 0.84 kg/ha for at least 95% control. At the three-leaf stage, all species except cheat ( Bromus secalinus L.) and red rice were highly susceptible to the herbicide at 0.56 and 0.84 kg/ha. At the six-leaf stage, 0.56 kg/ha of metriflufen gave 96% control of Texas panicum ( Panicum texanum Buckl.) and goosegrass [ Eleusine indica (L.) Gaertn.], but 0.84 kg/ha was necessary for 92% control of barnyardgrass [ Echinochloa crus-galli (L.) Beauv.] and 85% control of large crabgrass [ Digitaria sanguinalis (L.) Scop.]. Except for cheat, metriflufen gave less than 55% control if applied when grasses were heading. Little postemergence control was evident for red rice.