Soybeans tolerant to growth regulator herbicides discussed at breakfast meeting

New herbicide-tolerant crops that will expand the weed control options for soybeans have been developed. However, they are not ready for the 2016 season.

The Integrated Pest Management (IPM) Breakfast Series is organized by the Michigan State University Extension field crops team in southwest Michigan. The meeting series runs through the end of June and is held on Tuesdays at the Royal Café in Centreville, Michigan, beginning at 7 a.m. Each meeting is open to the public and includes updates of the major field crops grown in the region, including a crop and pest report, followed by a guest speaker presentation.

On May 3, 2016, Rod Stevenson from Monsanto and Dave Hillger from Dow AgroSciences discussed their respective company’s new weed control systems in soybeans. They also provided updates on the progress for bringing these new products to market.

Controlling broadleaf weeds in soybeans can be a challenge, particularly with weeds that have become resistant to glyphosate and other commonly used herbicides in corn and soybeans in Michigan and throughout the Midwest. MSU Extension weed specialist Christy Sprague has excellent publications on managing three of the more common herbicide-resistant weeds in Michigan: horseweed (marestail), common waterhemp and Palmer amaranth.

The two technologies that each of the speakers discussed add another effective herbicide Site of Action (SoA) group to current weed control systems in soybeans that may help control and delay the further development of herbicide resistance. These technologies involve soybean varieties that are resistant growth regulator herbicides that have been used to control broadleaf weeds for decades. Dow AgroSciences’ Enlist Soybean allows for in-crop use of 2,4-D and glyphosate, and Monsanto’s Roundup Ready 2 Xtend Soybean can tolerate in-crop applications of dicamba and glyphosate.

The speakers discussed the development of new herbicide formulations for each of these active ingredients that are less prone to volatilization (e.g., vapor drift) and particle drift, decreasing the risk of injury to surrounding sensitive plants. They also explained the Environmental Protection Agency (EPA) requirement of including prescribed nozzles that must be used when spraying these herbicides to reduce drift potential, something that is unprecedented on herbicide labels, but that is likely to be a new requirement for all new pesticide labels in the future.

The approval process for growing these soybeans involving the United States Department of Agriculture, China and European Union is ongoing. Therefore, growers are not advised to grow these varieties in 2016. Also, EPA has yet to register dicamba herbicide for pre-emergence and post-emergence use in a soybean crop. However, both speakers were optimistic their respective weed control systems would be available to growers for the 2017 season.

The speaker for May 17 will be Christy Sprague, who will be addressing the topic, “Field Crop Weed Issues.” The meeting will be sponsored by Dale Hiatt with Crop Production Services, Mendon, Michigan. CEU and RUP credits will be available. All interested persons are welcome to attend.

For more information on the IPM Breakfast Series, contact Eric Anderson at the MSU Extension St. Joseph County office at 269-467-5511.

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