Flumioxazin: A new tool for hairy nightshade control in potato production.

Authors: Boydston, Rick; HUTCHINSON, P - UNIV OF IDAHO, ABERDEEN

Submitted to: Abstracts of the Sixth World Potato Congress
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/2006
Publication Date: 2/9/2007
Citation: R. A. Boydston and P. J. S. Hutchinson. Flumioxazin: A new tool for hairy nightshade control in potato production. Abstracts of the Sixth World Potato Congress, Boise, ID. www.potatocongress.org.

Interpretive Summary: Flumioxazin was tested at 53 g ai/ha as a tank mix partner for hairy nightshade (Solanum sarrachoides) control in potatoes near Aberdeen, ID, and Paterson, WA from 2001 to 2005. Herbicides were applied after final hilling and preemergence (PRE) to potato and weeds and sprinkler incorporated. Studies in Washington were conducted on a Quincy sand, pH 7.0 containing 0.4% O.M, and in Idaho, on a Delco silt loam soil, pH 8.1 containing 1.4% O.M. In Washington, flumioxazin applied PRE with metribuzin, pendimethalin, EPTC, s-metolachlor, or rimsulfuron, significantly increased hairy nightshade control to 99% or more. In Idaho studies, the same two-way tank mixtures provided 90% or greater hairy nightshade control. No significant potato injury was observed with flumioxazin tank mixtures at either location. In Washington, where the studies were conducted on sand with low organic matter, redroot pigweed (Amaranthus retroflexis) was controlled well with the flumioxazin two-way tank mixtures. In contrast, redroot pigweed control was not acceptable with the two-way mixtures in Idaho unless flumioxazin was combined with metribuzin or rimsulfuron. However, control was improved with three-way tank mixtures in Idaho. Control differences between the locations may have been due to the slightly finer-textured soil with higher %O.M. in Idaho possibly causing less herbicide availability and less effective control. In general, potato yields were greatest when weed control was adequate and lowest in treatments that resulted in poor weed control.

Technical Abstract: Flumioxazin was tested at 53 g ai/ha as a tank mix partner for hairy nightshade (Solanum sarrachoides) control in potatoes near Aberdeen, ID, and Paterson, WA from 2001 to 2005. Herbicides were applied after final hilling and preemergence (PRE) to potato and weeds and sprinkler incorporated. Studies in Washington were conducted on a Quincy sand, pH 7.0 containing 0.4% O.M, and in Idaho, on a Delco silt loam soil, pH 8.1 containing 1.4% O.M. In Washington, flumioxazin applied PRE with metribuzin, pendimethalin, EPTC, s-metolachlor, or rimsulfuron, significantly increased hairy nightshade control to 99% or more. In Idaho studies, the same two-way tank mixtures provided 90% or greater hairy nightshade control. No significant potato injury was observed with flumioxazin tank mixtures at either location. In Washington, where the studies were conducted on sand with low organic matter, redroot pigweed (Amaranthus retroflexis) was controlled well with the flumioxazin two-way tank mixtures. In contrast, redroot pigweed control was not acceptable with the two-way mixtures in Idaho unless flumioxazin was combined with metribuzin or rimsulfuron. However, control was improved with three-way tank mixtures in Idaho. Control differences between the locations may have been due to the slightly finer-textured soil with higher %O.M. in Idaho possibly causing less herbicide availability and less effective control. In general, potato yields were greatest when weed control was adequate and lowest in treatments that resulted in poor weed control.