Several weedy biotypes of wild-proso millet occur throughout Ontario. Field and laboratory studies were conducted in 1986 and 1987 to evaluate imazethapyr for preemergence and postemergence control of wild-proso millet. In the laboratory, imazethapyr, applied postemergence, effectively controlled weedy biotypes of wild-proso millet in the 4- to 5-leaf stage. Seedlings of black-seeded wild-proso millet were controlled at the 1- to 5-leaf stage by 50 g ai/ha of imazethapyr. Higher doses of imazethapyr were required to control later growth stages. In field studies, imazethapyr, applied preemergence or postemergence, effectively controlled black-seeded wild-proso millet, resulting in soybean yields comparable to the recommended postemergence treatment of sethoxydim.
