EPA releases interim registration review decision for 22 sulfonylurea herbicides

EPA recently released its interim registration review decision for 22 sulfonylurea herbicides. Among the 22 herbicides reviewed are two that are commonly used for forest vegetation management: metsulfuron methyl and sulfometuron methyl. The announcement was published in the September 20, 2017 issue of the Federal Register (82 FR 43962). 

This decision is designated as “interim” rather than “final” because endangered species, endocrine disruption, and pollinator assessments have not yet been completed. The interim decision establishes a set of common labeling requirements for all 22 sulfonylurea herbicides, along with specific labeling requirements for some individual herbicides. The components of the new labels for metsulfuron methyl and sulfometuron methyl that will be of most interest to NCASI member companies are those related to spray droplet size and buffer requirements.

The new label for metsulfuron methyl mandates the use of spray droplets of coarse or coarser droplet size (ASABE S572.1) for aerial applications made prior to the emergence of crops and target weeds and medium or coarser droplet size (ASABE S572.1) for all other aerial applications. These requirements are consistent with current standard practices by applicators. There are no buffer requirements, although the label specifies that “applicators must use ½ swath displacement upwind at the downwind edge of the field.”

The new label for sulfometuron methyl contains a droplet size restriction different from the standard sulfonylurea label: “Applicators are required to use an Extremely Coarse or coarser droplet size (ASABE S572.1) for all applications,” which results in an additional constraint on applicators. However, as with metsulfuron methyl, there are no buffer requirements other than the requirement of ½ swath displacement at the downwind edge of the field.

The interim decision is available online at https://www.regulations.gov/document?D=EPA-HQ-OPP-2011-0375-0068. For additional information, contact Dr. Vickie Tatum at the NCASI Southern Regional Center.

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