Giant Ragweed and Waterhemp Confirmed Resistant to Glyphosate in Minnesota

Glyphosate-resistance may follow pattern of other resistant herbicides

Jeffery Gunsolus, an agronomist and weed scientist of the University of Minnesota, in AgricultureOnline predicts that the spread of glyphosate-resistant weeds will follow the pattern of other herbicide resistance, beginning slow and then increase at an alarming rate, after the announcement confirming glyphosate-resistant giant ragweed and waterhemp in the state.

What can growers do? Syngenta recently asked growers and retailers across the U.S. what they are doing to fight glyphosate-resistant weeds in their fields. Consistently, they responded with practices such as rotating crops, including additional modes of action, using pre-emergence residual herbicides, limiting glyphosate use, implementing tillage as needed among others.

Gunsolus agrees, offering seven points to consider when implementing into your weed management program. Here are a few to consider:

·         Utilize other modes of action through use of a pre-emergence herbicide or a tank mix partner.

·         As the growing season moves into high gear don’t forget to scout your fields approximately 10 to 14 days after your first glyphosate application to detect weed escapes. If the weeds survive, determine why.

·         Keep in mind that many post-emergence herbicides have crop size restrictions.

Minnesota is the most recent state to confirm glyphosate-resistant weeds, but will not be the last. Glyphosate weed resistance has the potential to explode this summer, and has made headlines because of it. What practices do you have, or plan to, put in place as part of a resistance management program? How valuable are glyphosate and glyphosate-tolerant crops to your operation?

For more information:

·         In addition to Minnesota a growing number of states that have confirmed glyphosate-resistant weeds. Click here to view the map.

·         Minnesota Crop eNews – University of Minnesota Extension

·         Glyphosate-Resistant Waterhemp: Challenges and Solutions

·         A Look at Giant Ragweed: Challenges and Solutions