Proposed Interim Registration Review Decision for Oxadiazon and Implications in Turfgrass Systems

U.S. Environmental Protection Agency released their Proposed Interim Registration Review Decision for Oxadiazon (Registration Review Case #2485) on August 3, 2021, which contains major changes.

Proposed changes include but are not limited to:
  • Deletion of all turfgrass use sites with the exception of golf course fairways and sod farms.  In other words, termination of oxadiazon use on all other turfgrass use sites including golf course tees, golf course roughs, parks, athletic fields, cemeteries, and other public areas.
  • When a liquid oxadiazon formulation is used on golf course fairways, a maximum single application rate of 3.0 lb ai per acre with use limited to one application per year.  Application of a liquid formulation may be followed by a single application of a granular formulation 120 days later.
  • Reduce maximum annual application rate from 8.0 lb ai to 6.0 lb ai per acre for turfgrass sites.
  • Wettable powder formulations prohibited.
  • Addition of verbiage to label including mechanism of action group and code as well as spray drift management verbiage.

What to do:

A full summary of the review may be found on the United States' Regulations website.

You are encouraged to provide comments and feedback about the proposed changes including the value of oxadiazon, how you use the product, and the impacts (agronomic and financial) of the proposed changes.  Comments must be submitted by 11:59 p.m. EDT on October 04, 2021, to be included and may be submitted electronically.