Managing volunteer potato (Solanum tuberosum) in field corn (Zea mays) with carfentrazone-ethyl and dicamba

Volunteer potato is a perennial weed that is difficult to control in crop rotations. Field studies were conducted near Paterson, WA, in 2001 and 2002 to evaluate the control of volunteer potato with carfentrazone-ethyl and dicamba in field corn. When potatoes were not controlled corn yield was reduced 23 and 62% in 2001 and 2002, respectively. Single postemergence (POST) applications of carfontrazone-ethyl at 9 g/ha killed exposed foliage of potato, but new shoots continued to emerge both years and reduced corn yield in 2002. The most effective treatments tested were a single mid-posternergence application of carfentrazone-ethyl plus dicamba (9 + 280 g/ha), two applications of carrentrazone-ethyl alone at early postemergence and late postemergence, and three POST applications of carfentrazone-ethyl, which controlled volunteer potato 77 to 87% in early June, reduced weight of tubers produced by 76 to 96% compared with nontreated checks, and prevented corn yield loss compared with hand-weeded checks. Herbicide treatments reduced potato tuber weight more than tuber number.