About this Session

Glyphosate-Resistant Grass Management in Corn

Presented by: Dr. Larry Steckel
Extension/Research Weed Scientist, University of Tennessee

Presented by: Clay Perkins
Graduate Student, University of Tennessee

Glyphosate has been the primary herbicide in corn to address johnsongrass infestations since the advent of Roundup Ready corn hybrids. However, in recent years University of Tennessee Extension has received numerous reports of johnsongrass, goosegrass and junglerice surviving often multiple applications of glyphosate. In particular, johnsongrass has become more problematic in corn. The beginning of this was in 2015 when populations from Tipton county were found to be 2 to 3 times more resistant to glyphosate than a susceptible population Since 2015, GR johnsongrass has becoming increasingly abundant in many counties across Tennessee. Due to the development of glyphosate resistance, johnsongrass is in the process of becoming the primary weed problem in our state’s corn production once again. Changes in weed management are now clearly needed in corn to address the increasing issues of GR grass weed species.