Field studies were conducted to evaluate preemergence weed control in irrigated potatoes with rimsulfuron plus metribuzin or three-way mixtures of rimsulfuron plus metribuzin plus EPTC, metolachlor, or pendimethalin. Redroot pigweed control was ≥ 96% with rimsulfuron plus metribuzin at 18 g ai/ha + 140 g/ha, and common lambsquarters control was ≥ 97% with rimsulfuron plus metribuzin at 26 g/ha + 210 g/ha. Hairy nightshade control with rimsulfuron plus metribuzin ranged from 58 to 99%, and green foxtail control ranged from 50 to 98%. EPTC, metolachlor, or pendimethalin rates required for acceptable green foxtail and hairy nightshade control in combination with a given rate of rimsulfuron plus metribuzin varied with environmental conditions. Potato tuber yield generally improved with rimsulfuron plus metribuzin application.
