Submitted to: Potato Progress
Publication Type: Popular Publication
Publication Acceptance Date: 1/1/2005
Publication Date: 2/1/2005
Citation: Boydston, R.A., Hutchinson, P.J., Ransom, C. 2005. New herbicides for weed management in potato production. Potato Progress. 5:1-2.
Technical Abstract: Weeds reduce potato yield and quality and several weed species, including nightshades are not consistently controlled by metribuzin, the main herbicide used in potato production. Three new herbicides, dimethenamid-p, sulfentrazone, and flumioxazin, selectively control hairy and black nightshade in potatoes. These three herbicides were tested over several years in potatoes for crop tolerance and weed control near Aberdeen, ID, Ontario, OR, and Paterson, WA. At all locations herbicides were applied after the final hilling and prior to potato and weed emergence, and incorporated with sprinkler irrigation. Sulfentrazone controlled pigweed species, hairy and black nightshade, common lambsquarters, kochia, and Russian thistle. Grass weeds were not controlled well with sulfentrazone, but was improved by tank mixing sulfentrazone with metribuzin, s-metolachlor, rimsulfuron, pendimethalin, or EPTC. All major potato varieties grown in the PNW exhibited tolerance to sulfentrazone. Some injury was observed on potato leaves in late May and early June when using higher than labeled rates of sulfentrazone. Minor to moderate injury symptoms on leaves have not resulted in reduced tuber yields in research trials unless the potatoes were experiencing heat stress at the same time as metabolizing the herbicide after root uptake. Dimethenamid-p controlled barnyardgrass, crabgrass, yellow foxtail, green foxtail, and small-seeded broadleaf weeds hairy and black nightshade and pigweed species alone and in tank mixtures with other herbicide registered on potato. All major potato varieties grown in the PNW exhibited good tolerance to dimethenamid-p. Flumioxazin controlled pigweed species, hairy and black nightshade, common lambsquarters, kochia, and Russian thistle. Nightshade species are very susceptible to flumioxazin and its use in potato will primarily be targeted as a tank mix partner to improve nightshade control. Pigweed and common lambsquarters control with flumioxazin was less consistent in silt loam soils with higher organic matter in Idaho and Oregon than in sandy soils with low organic matter in Washington State. Grass weeds were not controlled well with flumioxazin at rates labeled for potatoes but was improved with tank mixing with metribuzin, s-metolachlor, rimsulfuron, pendimethalin, or EPTC. Major potato varieties grown in the PNW exhibited good tolerance to flumioxazin.