2020 Dicamba Update and Resources

Last updated November 19, 2020

The Take Action program — supported by the soy checkoff in cooperation with endorsing partners, including 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 2021 growing season and beyond.  



On October 27, the U.S. Environmental Protection Agency announced registration of three dicamba formulations for over-the-top use in dicamba-tolerant soybeans and cotton for five years. Approved herbicides include XtendiMax® (Bayer), Engenia® (BASF) and Tavium® (Syngenta). The new registration begins in 2021 and will last through 2025. 


The EPA updated guidance on October 27, 2020. Updated control measures for growers and applicators in 2021 include the following:

-    Required 240-feet downwind in-field buffer and 310-feet downwind buffer for any endangered species.
-    Limit of two over-the-top applications of dicamba per field per year for both dicamba-tolerant soybeans and dicamba-tolerant cotton.
-    Applications only permitted between one hour after sunrise and two hours before sunset.
-    Nationwide calendar cutoff dates for application on dicamba-tolerant soybeans of June 30 and July 30 for dicamba-tolerant cotton.
-    Additional recordkeeping and training requirements.

For a full list of updated control measures, view the table on page 4 of the EPA guidance. 


To delay the onset of dicamba resistance in weeds, an integrated weed management program is necessary. It is not recommended to rely solely on dicamba to control weeds. Rotate sites of action and implement cultural weed management practices to help manage resistance.

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. 

Choosing to apply dicamba products outside their labeled use — such as applying during temperature inversions or using incompatible nozzles — can increase the risk of causing damage to sensitive neighboring crops. In addition, applying outside the labeled rates can accelerate the development of resistant weed populations.



●    Managing 2,4-D and Dicamba Fact Sheet
●    Take Action Herbicide Classification Chart
●    Take Action Palmer Amaranth Management in Soybeans Fact Sheet
●    Take Action Waterhemp Management in Soybeans Fact Sheet
●    Take Action Kochia Management in Soybeans Fact Sheet
●    Take Action Giant Ragweed Management in Soybeans Fact Sheet
●    Take Action Marestail Management in Soybeans Fact Sheet



  • Registration of Three Dicamba Products
    • Official communication from the EPA containing the rationale to support their decision to allow registrations of dicamba products.
    • Source: Environmental Protection Agency (EPA)
    • Publish Date: 10/27/2020




Other Options for Managing Resistant Weeds



  • Managing herbicide-resistant waterhemp in dicamba-resistant soybean
    • Take Action partner Bob Hartzler with colleagues Prashant Jha and Meaghan Anderson provide recommendations on managing herbicide-resistant waterhemp during the 2020 soybean growing season.
    • Source: Iowa State University Extension and Outreach Integrated Crop Management
    • Publish date: 6/5/2020


For more information on dicamba stewardship, please visit the following websites:


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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