Respect the Rotation: glyphosate-resistant weeds one year later

Growers, consultants, weed scientists, researchers and government agency officials who participated in the July 2010 launch of the Respect the Rotation™ initiative have taken measureable steps toward progress in the fight against the proliferation of glyphosate-resistant weeds. But university experts still believe the system will fail if current practices continue.

There is enough of an ominous threat to current agricultural production practices that government officials have taken an interest in the topic. Armed with that knowledge, one initiative to come from the 2010 Respect the Rotation field day urges growers to remember their on-farm management practices from a time before glyphosate resistance was widespread when diverse management practices discouraged the development, and additional cost, of resistant weeds.

"Glyphosate-resistant marestail costs soybean growers an added $11.50 per acre,” said Jason Norsworthy, associate professor of weed science at the University of Arkansas and a key member of the Weed Science Society of America (WSSA) who is working with the Environmental Protection Agency to develop guidelines for proper resistance management practices. “Glyphosate-resistant Palmer pigweed costs cotton growers $19.45 per acre. Resistance is impacting land values, conservation tillage and more. The system, the way it is currently set up, is not sustainable.”

Norsworthy and other WSSA members are working diligently with other government agencies to develop incentives for proper stewardship of glyphosate-tolerant technologies and encourage proactive management strategies. This cooperation will spur producers to stay ahead of weed resistance and raise a profitable crop.

Bayer CropScience Commitment

In a move to make rotation easier for growers, Bayer CropScience is voluntarily labeling all herbicide modes of action on herbicide containers for easy identification. “If growers can see the numbering system associated with various chemistries and easily identify what mode of action they’re applying, they can better identify opportunities for herbicide rotation” said Andy Hurst, product manager for Bayer CropScience. “Without that knowledge, it is easy to apply the same mode of action over and over, encouraging the development of resistance.”

Bayer CropScience is today the sole company to offer LibertyLink®, the only nonselective alternative to glyphosate-tolerant systems. The LibertyLink trait with Ignite® herbicide enables growers to keep weed management efficient while providing an effective tool to manage resistance.

Ignite herbicide features a unique mode of action that offers a nonselective choice for Integrated Weed Management plans. Ignite is labeled for over-the-top use on all LibertyLink crops, including corn, cotton, canola and soybeans.

The recent launches of several new corn herbicides from Bayer, Laudis® herbicide, Corvus® herbicide, Capreno® herbicide and Balance® Flexx herbicide, are excellent tools to ensure consistent, season-long weed control, including control of those weeds that have exhibited a tolerance to glyphosate.

Additionally, Bayer CropScience is working hard to provide growers with sustainable weed management solutions in the future. For example, Bayer has entered into collaborations with other companies to develop new herbicide-tolerant traits in soybeans, offering a broad range of distinct modes of action, such as HPPD inhibitors.

This confirms the Bayer CropScience commitment to the Respect the Rotation initiative to overcome weed management challenges, which will enable U.S. farmers to grow broad-acre crops profitably.

Flag the Technology

Another proposal from the 2010 Respect the Rotation event is the Flag the Technology program spearheaded by the University of Arkansas. Colored flags are placed around a field to help prevent herbicide misapplication and to warn of technology that is sensitive to potential off-target chemical drift. The colored flags help applicators easily identify what technology is planted to a particular field.

The University of Arkansas has promoted the effort and helped standardize the size of the flags and what each flag color means. LibertyLink fields are identified with green flags, signifying it’s tolerant to Ignite herbicide. Roundup Ready® varieties are marked with white flags. Conventional fields are identified with the color red.
Reports indicate fields have been saved from accidental misapplication by the colored flags.

"This will help growers be conscientious of what’s in their fields and their neighbors’ fields,” Hurst said. “Rotation encourages diversity and leads to stronger management against resistant weeds. The flag system offers growers who rotate herbicide-tolerant traits peace of mind.”

Looking Ahead

Attendees of both the 2010 and 2011 Respect the Rotation meetings were shocked at the scope and breadth of glyphosate-resistant Palmer pigweed in the Mid-South and other resistance weed species that are creating concern. To see firsthand how much money was invested in Palmer pigweed control and to watch fields being plowed under because of out-of-control weeds, was a wakeup call to many.

In 2011, Bayer CropScience has taken the Respect the Rotation story to the Midwest. Building on the success of last year’s Respect the Rotation event, this year there were six field days throughout the Midwest. Topics have centered on weed resistance – what the problem is and how to manage it – on sites from Nebraska to Ohio to southern Illinois and Iowa.

"Producers have been offered an intimate look at what weed resistance looks like locally and what it means for their farms,” Hurst says. “We teamed with university experts across the Midwest to set up plots that demonstrate glyphosate weed resistance and the best programs available for control based on local conditions.”

Respect the Rotation is an initiative to elevate the importance and grower adoption of herbicide diversity. The Respect the Rotation Field Tours scheduled for 2011 have brought the issue to the doorstep of those who can benefit most from its message.

"We’re moving in a positive direction and offering choices to break the cycle of continuous glyphosate use,” says Jim Blome, President/CEO of Bayer CropScience North America. “I’m looking forward to making even greater strides in the coming year.”

Source: Bayer CropScience