Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 8, 2007
Publication Date: April 1, 2007
Citation: Boydston, R.A. 2007. Potato (Solanum tuberosum) and Weed Response to Postemergence Applied Halosulfuron, Rimsulfuron, and EPTC. Weed Technology. 21:465-469. Interpretive Summary: Control of emerged broadleaf weeds in potatoes is limited as only metribuzin and rimsulfuron are registered for this use. Halosulfuron is currently being evaluated for preemergence and postemergence (POST) weed control in potato and suppresses yellow nutsedge, a difficult to control weed in potato production. These studies were conducted to determine potato and hairy nightshade response to halosulfuron applied POST alone and in tank mixes with rimsulfuron or low rates of EPTC. Halosulfuron applied POST had marginal selectivity on potato and failed to control hairy nightshade, a major problem weed in Western potato growing regions. Tank mixing rimsulfuron with halosulfuron improved control of hairy nightshade and large crabgrass and increased potato yield. Halosulfuron controlled low densities of redroot pigweed and common lambsquarters and could prove useful in fields where those species predominate. However, tank mixing halosulfuron with herbicides that control hairy nightshade would likely be required in most instances.
Technical Abstract: Weed control and potato response to halosulfuron applied alone postemergence (POST) and with rimsulfuron or EPTC was evaluated in 2004 and 2005 near Paterson, WA. Potatoes were injured and exhibited chlorosis and stunted growth following halosulfuron applications of 18, 26, and 35 g/ha. Potato height was reduced 33% and 20% in late May by halosulfuron at 18 or 26 g/ha in 2004 and 2005, respectively. Halosulfuron applied alone failed to control hairy nightshade and large crabgrass. Total tuber yield and U.S. No. 1 yield were reduced 10% in halosulfuron-treated plots due to poor weed control and possibly herbicide injury. Tank mixing rimsulfuron with halosulfuron improved control of hairy nightshade and large crabgrass and increased potato yield. Tank mixing EPTC at 2 kg/ha with halosulfuron improved early season hairy nightshade control, but weed control was poor at row closure. Rimsulfuron applied alone at 18 or 26 g/ha controlled hairy nightshade and large crabgrass without potato injury and resulted in the greatest potato yields.