Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2000
Publication Date: 3/1/2001
Citation: HUTCHINSON, P.J., TONKS, D.J., RANSOM, C.V., EBERLEIN, C.V., BOYDSTON, R.A., BRINKMAN, B.A. DIMETHENAMID-P: WEED CONTROL AND POTATO CROP TOLLERANCE IN THE PACIFIC NORTHWEST. PROCEEDINGS OF WESTERN SOCIETY OF WEED SCIENCE. 54:42, #58. 2001. Interpretive Summary:
Technical Abstract: Efficacy and potato tolerance to dimethenamid-P was tested in field studies in Idaho in 1998, 1999, and 2000, and Oregon 1999 and 2000 and Washington 2000. In all trials herbicides were applied after hilling and prior to potato and weed emergence. Dimethenamid-p was sprinkler incorporated immediately after application. 'Russet Burbank' tolerance trials were kept weed-free during the season. The 1X rate of dimethenamid-p at 0.64 lb/a was compared to the 2X and 4X rates of dimethenamid-p (1.28 and 2.56), the 2X rate and 4X rates of s-metolachlor (2.6 and 5.2 lb/A), and the 2X rate of dimethenamid (2.34 lb/A). Early leaf injury consisting of leaf crinkling and malformation, was observed until approximately 3 weeks after emergence. Visual symptoms were not evident at row-closure except in Idaho 1998. Total tuber and U.S. No. 1 tuber yields were not significantly different among treatments including a weed-free check. In efficacy trials, 0.64 lb/A dimethenamid-p provided greater than 95% redroot pigweed control, 85 to 90% common lambsquarters and hairy nightshade control, and less than 70% tame oat control. Tank- mixing dimethenamid-p with metribuzin (0.5 lb/A) or rimsulfuron (0.023 lb/A) improved hairy nightshade, common lambsquarters, and tame oat control to greater than 95%. Rimsulfuron + metribuzin (0.023 + 0.5 lb /A) provided greater than 95% control of redroot pigweed, common lambsquarters, and tame oat, and 91% hairy nightshade control. Metribuzin alone controlled hairy nightshade 73%. Dimethenamid-p tank-mixtures with sulfentrazone or flumioxazin provided greater than 95% redroot pigweed, common lambsquarters, hairy nightshade, and tame oat control in 2000 Idaho and Washington efficacy trials.