February 9, 2009

Idaho growers transitioned to herbicide-resistant sugarbeets in 2008, reducing the number of times farmers had to apply herbicides or hire field labor to control weeds.

University of Idaho Extension weed scientist Don Morishita at Kimberly is working to ensure that three common weeds, lambsquarters, redroot pigweed, and kochia, do not develop their own herbicide resistance. The turning point for sugarbeet growers’ decisions to use Monsanto’s Roundup Ready technology in their fields was encouragement from the Amalgamated Sugar Co., Morishita said.

His work now focuses on refining weed control recommendations, which typically involve two or more herbicides to ensure weeds do not survive and begin to develop herbicide resistance. The main strategy will use glyphosate, the active ingredient in Roundup, to control emerged weeds with another herbicide with soil activity for control.

The approach may require growers to apply herbicides only once or twice a season rather than four or five times as they did with conventional beets, he said.

Southern Idaho growers have not faced problems with glyphosate-resistant weeds, Morishita said. However, in the Midwest, where Roundup Ready soybeans and corn are planted extensively, glyphosate resistance is a problem.

Website: http://www.uidaho.edu

Published: February 9, 2009