Last updated July 1, 2020
Take Action, in cooperation with endorsing partners including the soy checkoff, as well as major agrochemical and trait companies, scientific organizations and experts affiliated with several land-grant universities, continues to be committed to providing resources to farmers for managing weeds and mitigating herbicide resistance on the farm. As part of that mission, Take Action will provide unbiased articles and researcher-vetted resources on dicamba to help you navigate the 2020 growing season.
On June 3, the U.S. Court of Appeals for the Ninth Circuit vacated the registrations for three dicamba herbicides previously approved through December 2020 for over-the-top application in soybeans with a dicamba-tolerance trait such as Xtend®. Affected herbicides include XtendiMax® (Bayer), Engenia® (BASF) and FeXapan® (Corteva Agriscience). This decision does not affect Tavium® (Syngenta), which was not yet registered at the time of the suit. Its registration is set to expire in December 2020. It is important to note that Tavium® can only be legally applied to soybeans through the V4 growth stage or within 45 days after planting, whichever comes first.
The Environmental Protection Agency updated guidance on June 8, 2020. Growers and applicators will be allowed to use existing stocks of the three impacted dicamba herbicides until July 31, 2020, but only existing stocks that were in their possession on June 3, 2020. The order prohibits use of existing stocks inconsistent with the previously approved product label. Some states may have specific cutoff dates ahead of July 31 for making applications. Applicators must follow the most restrictive regulations.
After the EPA published its cancellation order, an emergency motion was filed asking the federal court to halt all dicamba use. On July 19, 2020, the EPA’s cancellation order, including the provisions for use of existing stock, was upheld by the court. Farmers and commercial applicators should continue to act in accordance with its directives, which allow them to use stocks of the affected dicamba formulations by July 31, 2020, or through their state’s cutoff date, whichever comes first.
Although the EPA cancellation order also discusses the legality of applying off-label for unregistered pesticides, this is not a recommendation in line with best practices for soybean farmers long term. Choosing to apply dicamba products outside their labeled use — such as applying during temperature inversions or using incompatible nozzles — not only violates the EPA cancellation order, but can cause damage to sensitive neighboring crops. In addition, applying outside the labeled rates can accelerate the development of resistant weed populations.
To delay the onset of dicamba resistance in weeds, an integrated weed management program is necessary. Dicamba should not be used as a POST-only approach but as part of an integrated residual herbicide program. It remains illegal to apply any dicamba herbicides not labeled for use in soybeans POST-emergence, even in dicamba-tolerant soybeans.
The United Soybean Board neither recommends nor discourages the implementation of any advice contained herein, and is not liable for the use or misuse of the information provided.
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