Wild oat (Avena fatua) control in spring wheat (Triticum aestivum) and barley (Hordeum vulgare) with reduced rates of postemergence herbicides

Rates and application timings of postemergence herbicides for wild oat control in spring wheat and barley were evaluated at Crookston, MN, from 1994 to 1996. Diclofop, imazamethabenz, and fenoxaprop plus MCPA plus thifensulfuron plus tribenuron were applied to one- to three-leaf wild oat; and difenzoquat, imazamethabenz, fenoxaprop plus MCPA plus thifensulfuron plus tribenuron, and fenoxaprop plus 2,4-D plus MCPA were applied to four- to five-leaf wild oat at 1/2 x, 3/4 x, and 1 x rates. Wild oat response to herbicide rate and timing was similar in wheat and barley. Wild oat control with 1/2 x rates generally was less than that with 3/4 x rates, which was lower than or similar to that with 1 x rates. Wild oat biomass was often reduced less with 1/2 x rates than 1 x rates. However, reducing herbicide rates generally did not influence grain yields or net economic return. Grain yields and net economic return were generally greater in herbicide-treated plots than in the nontreated control.