Preemergence Herbicides for Potential Use in Potato Production

Field trials were conducted in 2009 and 2010 near Paterson, WA and Ontario, OR to evaluate weed control and potato tolerance to PRE-applied pyroxasulfone, saflufenacil, and KSU12800 herbicides. Pyroxasulfone at 0.09 to 0.15 kg ai ha(-1) and saflufenacil at 0.05 to 0.07 kg ai ha(-1) applied PRE alone or in tank mixes with several currently labeled herbicides did not injure potatoes at either site in both years. KSU12800 at 0.15 kg ai ha(-1) injured potatoes from 18 to 26% for a period of about 4 wk after emergence at Ontario both years. In addition, KSU12800 at 0.29 and 0.45 kg ha(-1) injured potatoes from 17 to 38% at 17 d after treatment (DAT) at Paterson in 2009. Pyroxasulfone at 0.15 kg ha(-1) controlled barnyardgrass, hairy nightshade, and redroot pigweed 96% or greater, but control of common lambsquarters was variable. Saflufenacil at 0.07 kg ha(-1) provided greater than 93% control of common lambsquarters, hairy nightshade, and redroot pigweed at both sites in 2010. KSU12800 at 0.15 kg ha(-1) controlled common lambsquarters, hairy nightshade, and redroot pigweed 99% or more at Ontario, but only 87 to 93% at Paterson in 2010. These herbicides did not reduce yield of U.S. no. 1 tubers or total tuber yields compared to standard labeled herbicide treatments when weed control was adequate.