Susceptibility of Rice (Oryza sativa) to Various Postemergence Grass Herbicides

A 4-yr study was conducted to evaluate the response of rice (Oryza sativa L. 'Starbonnet′) to sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl-3-hydroxy-2-cyclohexen-1-one}, haloxyfop {2-[4-[13-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid}, fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid}, and quizalofop {(±)-2-[4-(6-chloro-2-quinoxalynyloxy)phenoxy] propanoic acid}. In general, rice was more sensitive when herbicides were applied at panicle initiation than at the tillering stage of development. Quizalofop severely reduced rice yield when applied wih a surfactant. Applied at tillering, sethoxydim at 210 g ai/ha did not reduce rice height, grain yield, milling yield, or seed quality.