Glyphosate-Resistant Johnson Grass Confirmed in Two Locations

A group of scientists from the University of Arkansas and a separate group from the Missisipi State University have confirmed cases of Johnson grass resistance to glyphosate in their respective states. Investigations with the Monsanto researchers were conducted during the past few months in greenhouse conditions which will be followed by an extensive field study this season.

Dr. Jennifer Ralston, U.S. chemistry technical lead for Monsanto, has called for a quick action to control the problem. “We are working with these university experts to provide growers with the best management practices. To maintain the efficacy of the herbicide and value of the technology, we recommend growers to scout fields and utilize additional modes of action that complement the Roundup Ready system to control problem weeds while reducing the likelihood of developing performance issues," she said. Among the recommended strategies include the following:

• Start with a clean field by either utilizing a burndown herbicide or early tillage to control weeds.
• Use Roundup Ready technology as the foundation of a total weed management program.
• Add other herbicides or cultural practices where appropriate as part of the Roundup Ready cropping system.
• Use the right herbicide rate at the right time.
• Control weeds throughout the season and reduce the weed seed bank.