Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Abstract only
Publication Acceptance Date: 12/1/2001
Publication Date: 3/1/2002
Citation: HUTCHINSON, P.J., BOYDSTON, R.A., RANSOM, C.V. EFFECTIVENESS OF DIMETHENAMID-P TANK MIXTURES FOR PREEMERGENCE WEED CONTROL IN POTATOES. PROCEEDINGS OF WESTERN SOCIETY OF WEED SCIENCE, 55:51, #104. 2002. Interpretive Summary:
Technical Abstract: Flumioxazin and sulfentrazone are two new mode-of-action herbicides being developed for use in potato to control hairy nightshade (Solanum sarrachoides), and other broadleaves. Field studies were conducted in Idaho and Washington in 2000 and 2001 to determine crop response of the four major potato varieties grown in the Pacific Northwest (PNW), Russet Burbank, Russet Norkotah, Ranger Russet, and Shepody to flumioxazin or sulfentrazone. Alturas and Bannock Russet were included in the 2001 Idaho trial. While neither herbicide reduced tuber yield in the 2000 Idaho trial, tuber yields of all six herbicide-treated varieties were reduced regardless of herbicide or rate compared to untreated controls in the 2001. Idaho experienced unusually high temperatures at or prior to row closure in 2001. Heat stressed plants may not have been able to rapidly metabolize the herbicides as needed for tolerance. Soil pH was higher in the 2001 ID location (8.4) compared to the 2000 ID location (7.9). These herbicides may be more mobile in higher pH soils, moving to the potato root zone with irrigation water, and causing more injury compared to injury occurrence in lower pH soils. Only two of the four varieties, Ranger Russet and Shepody, were more greatly affected by herbicide treatments in the Washington trial compared to the untreated controls. Even though the Washington soil had less organic matter for possible herbicide sorption, pH was closer to sulfentrazone pKa, and mobility may have been less than what would occur in a higher pH soil, such as in the Idaho trials. Washington also experiences a longer growing season than eastern Idaho, and initial injury may not have translated to as much tuber yield loss in Washington as plants recovered.