"Re"-Registration of Dicamba Herbicides
By now, you have read or heard that the US-EPA has registered dicamba herbicides for use on dicamba-tolerant (DT) cotton and soybeans over the next 5 years. This decision was made with the stipulation of additional restrictions on this auxin herbicide. You can access EPA’s documents that supplement this registration by clicking the below links.
Registration of Dicamba for Use on Dicamba-Tolerant Crops–US-EPA. A timeline (2018 to Oct. 27, 2020) of EPA activities regarding dicamba, with links to supporting documentation for these activities.
EPA Announces 2020 Dicamba Registration Decision–10/27/20–US-EPA Press Release. Announcement of EPA’s 5-year registration of two dicamba products (XtendiMax with Vapor Grip Technology and Engenia) and extended registration of an additional dicamba product (Tavium Plus VaporGrip Technology). These registrations are only for use of these herbicides on DT cotton and soybeans. This new registration features important control measures to manage offsite movement of this auxin herbicide.
Dicamba 2020 Registration Decision–Frequently Asked Questions–US-EPA. A list of 9 frequently asked questions regarding the 2020 registration decision, along with EPA’s response to these questions.
Dicamba Use on Dicamba-Tolerant Cotton and Soybeans–US-EPA Docket. Links to numerous EPA articles regarding the 2020 registration decision.
In a Bayer News Release dated Oct. 27, 2020, the virtues of XtendiMax dicamba herbicide (one of the registered dicamba products) are highlighted in an article titled “The U.S. EPA Announces New 5-Year Registration for XtendiMax Herbicide, Bayer’s Low-Volatility Dicamba Product“. This industry document includes some of the label changes that should further ensure the successful use of this herbicide by growers.
In an Oct. 27, 2020 article titled Engenia Herbicide Updates, BASF announced the EPA-approved registration of its Engenia dicamba herbicide. This industry document includes links to the “2020 Engenia Herbicide Label”, a “Guide to Important Label Changes”, and the “Sentris Buffering Technology” that BASF is promoting as a qualified buffering adjuvant for use with Engenia.
A DTN article by Emily Unglesbee titled “EPA Registers Dicamba Again“ summarizes major points in the above EPA decision, and provides supplemental background information regarding use of dicamba.
The above “re-registration” of dicamba herbicides does not change the following issues when using any auxin herbicide–e.g. dicamba and 2,4-D.
• Be reminded that DT soybean varieties are not tolerant of 2,4-D, and Enlist varieties are tolerant of 2,4-D, but not of dicamba. This remains a very important point when using varieties that are tolerant of different auxin herbicides.
• Be reminded that the issues associated with both drift and volatilization of auxin herbicides are still significant, and special care must always be exercised when using them. This has not and likely will not change in the foreseeable future, although the new labels for dicamba herbicide products will contain additional stipulations to address this.
• Preliminary research indicates that injury to soybeans from 2,4-D drift and volatility will be less than that from dicamba; however, injury from offsite movement of 2,4-D will still occur. Objective documentation of this is lacking, but results from recent research with this issue will be forthcoming (click here for a Farm Progress article that highlights ongoing research with this issue).
Composed by Larry G. Heatherly, Oct. 2020, larryheatherly@bellsouth.net