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Focus Is On Glyphosate Weed Resistance

Focus Is On Glyphosate Weed Resistance

"Respect the Rotation" is a program promoting best management practices for herbicide stewardship and avoiding weed resistance problems. Iowa growers got a hands-on look at recent field day.

At the recent Respect the Rotation field day in Ames, Iowa on Sept. 13 and 14, 2011 sponsored by Bayer CropScience, 200 people heard how continual use of a herbicide with a single mode of action intensifies selection pressure and contributes to the development of weed resistance. They also boarded busses and went north of Ames to Ellsworth, Iowa, and viewed weed management plots to see first hand how bad "weeds gone wild" can be.

Farmers in the Southern U.S. have already learned the hard way. Due to continued use of glyphosate herbicide in cotton and soybeans, severe weed resistance problems have developed. Palmer amaranth, a type of pigweed, has taken over many fields the past few years in the mid-South and Southeast states.

Several weed researchers from Arkansas attended the meeting at Ames and warned Iowa farmers and dealers that the same type of problem is going to develop soon in the Upper Midwest—if farmers don't use a more diversified weed control program.

What's happened in Southern U.S. is a warning for Midwest farmers

As the situation that is now occurring in the Mid-South indicates, growers in Iowa and other Midwest states have a narrow window to take advantage of and stay ahead of the weed resistance issue. Weeds can develop resistance to glyphosate faster than many farmers think. "Weed management plans farmers in Iowa are making for 2012 should not rely so heavily on glyphosate," said Ford Baldwin, a retired University of Arkansas weed scientist who now has his own private consulting firm in Arkansas.

Attendees at the meeting at Ames also saw the results of the continuous glyphosate approach to weed management, when they viewed the plots on the farm near Ellsworth, Iowa.

"The problem of glyphosate-resistant waterhemp is something that we need to get under control," stated Mike Owen, weed scientist at Iowa State University, who was one of the speakers at the field day. "The costs associated with weed control continue to increase. Weed resistance to herbicides is a threat to profitability. Growers need to make sure diversity is a key part of their weed management program."

Using proactive weed management is cheaper than being reactive

One participant from Pocahontas County in northwest Iowa agrees. "Being proactive is cheaper than being reactive."

Attendees at the field day also heard about Bayer's endeavor into seed, germplasm and traits, as well advances in innovative solutions for weed resistance management. "This meeting and plot tour gave us an opportunity to share how excited we are about the future of trait technology at Bayer and the investment in the soybean pipeline," says Andy Hurst, product manager for Bayer CropScience.

Growers were also able to learn how Bayer Innovative Solutions can be incorporated into their management programs. Plots included a wide-range of Bayer products including, LibertyLink® technology and Ignite® herbicide, as well as other crop protection solutions.

Rotating use of herbicides with different modes of action is wise move

"LibertyLink and Ignite fit very well into the principles of Respect the Rotation," says Hurst. "The goal of the initiative is to promote grower adoption of diversified management practices that help manage or prevent glyphosate-resistant weeds, as well as promote stewardship of viable alternatives. And, LibertyLink soybeans are a perfect fit."

The learning experience was a valuable one. "Glyphosate weed resistance is coming," says Amy Asmus, a certified crop advisor with Asmus Farm Supply at Rake in northern Iowa. "We have no more tries. We just need to do what needs to get done to control resistance."

Respect the Rotation is an initiative to elevate the importance and grower adoption of herbicide diversity, says Hurst. Rotating crops, and rotating herbicide-tolerant traits and modes of action are essential to improve weed resistance management. The Respect the Rotation Field Tours that were held in Iowa and other states in 2011 helped bring the issues to the doorsteps of those who can benefit most from its message.

To find out more about weed resistance management or Respect the Rotation, visit Also, you can Tweet this: Respect the Rotation Media Day in Ames, IA 9/14 talks need for diversity and change in herb. programs bc of #waterhemp #resistance. #RtR2011. Follow @Bayer4CropsUS on Twitter.

TAGS: Soybean USDA
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