Response to Ethofumesate of Annual Bluegrass (Poa annua) and Overseeded Bermudagrass (Cynodon dactylon)

Annual bluegrass (Poa annuaL.) was controlled in bermudagrass [Cynodon dactylon(L.) Pers.] turf when ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] was applied at 1.1 kg/ha in October and again in November, but not when applied in February and March. A single, October ethofumesate treatment, did not affect spring growth of nonoverseeded bermudagrass, but the growth of selected cultivars was delayed slightly from October + November treatment. Turf growth was severely delayed for all bermudagrass cultivars when ethofumesate treatments were delayed until February and March. The October and November ethofumesate treatments reduced the quality of overseeded perennial ryegrass [Lolium perenne(L.) ‘Medalist VI’] slightly, but did not injure it permanently and the turf recovered fully. The transition from ryegrass back to bermudagrass turf was good in the spring regardless of ethofumesate treatment. Even though turf cover was excellent throughout the transition period, bermudagrass cover during June and July was less when ethofumesate was applied in October than when application was delayed until after bermudagrass became dormant.