by Rodrigo Werle (UW-Madison Extension Cropping Systems Weed Scientist)
On October 31, 2018 the United States Environmental Protection Agency (EPA) announced their decision to extend the registration of the dicamba products Engenia, Fexapan, and Xtendimax for use in dicamba-tolerant crops (Xtend technology) through December 20, 2020; however, additional label changes were made.
A particular change that has led to some questioning is the new 57-foot omnidirectional buffer requirement to protect federally listed threatened and endangered species and critical habitat in specific US counties. On November 19, 2018, EPA posted the list of US counties where threatened and endangered species and critical habitat may exist (thus locations where the new 57-foot buffer must be incorporated). 218 US counties in 24 states are listed; see maps and figure below:
Maps generated my Dr. Maxwel Oliveira, UW-Madison Weed Science Research Associate. Information obtained on December 11, 2018.
Another significant label change pertaining to buffer requirements is that additional non-sensitive areas may be included as part of the 110-foot downwind buffer and also the 57-foot omnidirectional buffer.
According to EPA, the following areas (“non-sensitive areas”) may be included in the buffer distance calculation when directly adjacent to the treated field edges:
- “Roads, paved or gravel surfaces, mowed and/or managed areas adjacent to field such as rights of way.”
- “Planted agricultural fields containing: corn, cotton, and soybeans.”
- “Areas covered by the footprint of a building, silo, or other man made structure with walls and or roof.”
Practical Implications for Certified Applicators:
It is required for certified applicators using these products (Engenia, Fexapan and/or Xtendimax) to follow the measures contained in the Endangered Species Bulletins for the area which they are applying the product.
To obtain Bulletins, consult https://www.epa.gov/endangered-species or call 1-844-447-3813 no more than six months before using the product. Applicators must use the Bulletin valid for the month in which they will apply the product.
In the listed counties where threatened and endangered species and critical habitat may exist, besides the 110-foot downwind buffer, 57-foot buffer around the other sides of the field (omnidirectional) are now required.
In counties where threatened and endangered species and critical habitat are not listed, the 110-foot downwind buffer still applies.
Non-sensitive areas described above may be included in the buffer distance calculation when directly adjacent to the treated field edges.
And remember, DO NOT spray if sensitive crops or residential areas are adjacent and downwind of application area.
For those interested in the additional pertinent changes in the dicamba label, please visit the EPA website: https://www.epa.gov/newsreleases/epa-announces-changes-dicamba-registration and read the registrants updated labels.