Wild oat, a competitive weed in corn, can be controlled by atrazine applied postemergence but at rates causing carryover problems on high pH soils rotated to susceptible crops. Experiments at Fargo, ND and Barnesville, MN were established in corn using atrazine rates ranging from 0.14 to 0.84 kg ai ha–1 supplemented with cyanazine to provide 1.68 kg ai ha–1 total triazine herbicide. Atrazine at 0.84 kg ha–1 plus cyanazine at 0.84 kg ha–1 controlled 2- to 3-leaf wild oat 40 to 55%, but control increased to 90 to 95% by adding tridiphane at 0.56 or 0.84 kg ai ha–1. In greenhouse experiments, tridiphane synergistically increased wild oat control by atrazine and cyanazine. Tridiphane applied 1 or 2 d before atrazine or before an atrazine-cyanazine mixture generally controlled wild oat similar to the tridiphane-triazine tank mix.
