Lincoln, Nebraska, USA
April 25, 2013

University of Nebraska-Lincoln greenhouse studies have confirmed glyphosate resistance in common waterhemp from six Nebraska counties: Antelope, Dodge, Lancaster, Pawnee, Seward, and Washington. Waterhemp, a summer annual broadleaf weed, was already one of the most problematic weeds in corn and soybean production, but glyphosate resistance adds a new wrinkle to its control. Glyphosate-resistant common waterhemp has been confirmed in 12 states over the last eight years.

Last year, we had several phone calls from growers about control failure of common waterhemp despite the repeated application of glyphosate (Figure 1). In fall 2012 common waterhemp seeds were collected from fields in selected counties (Antelope, Dodge, Lancaster, Pawnee, Seward, and Washington) and glyphosate dose response studies were conducted in a UNL greenhouse. Glyphosate (Touchdown HiTech) was applied at several rates (0.25x to 16x the recommended rate of 24 fl oz/acre) to confirm level of resistance in common waterhemp populations.

Full report

Website: http://www.unl.edu

Published: April 27, 2013