Postemergence Green Foxtail (Setaria viridis) Control in Corn (Zea mays) in Western Canada

Field research was conducted to determine the effectiveness of DPX-79406 (a 1:1 mixture of nicosulfuron and rimsulfuron) for green foxtail control in field corn. Green foxtail control was similar when DPX-79406 was applied postemergence compared to preplant incorporated EPTC/dichlormid or metolachlor. DPX-79406 gave similar green foxtail control to that of cyanazine and better control than inter-row cultivation following soil-applied herbicides. Green foxtail control was greatest when DPX-79406 was applied at the one- to two-tiller stage compared to the one- to two-leaf stage, suggesting that green foxtail is more susceptible to DPX-79406 at later growth stages. DPX-79406 injured ‘Pioneer 3995’ corn in all trials but injured ‘Pride K020’ corn in only one treatment. DPX-79406 between 15 and 25 g ai/ha gave 85% control of green foxtail with minimal corn injury. Adjuvants tended to increase both corn injury and green foxtail control with Scoil and Merge increasing DPX-79406 activity the most. DPX-79406 provides an effective postemergence alternative for green foxtail control in field corn, for either preplant incorporated herbicides or postemergence cyanazine.