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EPA releases interim decisions on multiple pesticide products in the Pyridine class of herbicides

Today, the U.S Environmental Protection Agency (EPA) is releasing interim decisions for clopyralid, dithiopyr and triclopyr to address ecological risks.  

The interim decision (ID) for dithiopyr finalizes enforceable mitigation measures to address spray drift risks of concern. The IDs for clopyralid and triclopyr finalize enforceable mitigation measures to address potential residues in compost in addition to spray drift. The compost mitigation measures for clopyralid and triclopyr include label language focusing on:

  • Reducing compost contamination by prohibiting off-site composting of treated plant matter and manure from grazing animals until residues have adequately declined (both clopyralid and triclopyr); 
  • Requiring pasture and turf applicators to notify the property owners/operators of the compost prohibition, and for the applicator to keep a record of this notification for two year (clopyralid only); 
  • Requiring registrants to participate in a stewardship program and provide educational outreach for those affected by herbicide residues in compost (clopyralid only); and, 
  • Removal of residential use on turf language from all labels (clopyralid only). 

Interim registration review decisions impose risk mitigation measures necessary to protect the environment pending additional assessments including an endangered species assessment.  

The pyridines and pyrimidines are a class of herbicides used to control broadleaf weeds, woody brush and aquatic plants in both agricultural and non-agricultural settings that vary among the herbicides. Agricultural use sites include grains, fruits, vegetables and other crops. Non-agricultural use sites include turf, industrial areas, roadsides and other non-agricultural sites.  

After reviewing and considering the public comments received on the proposed interim decision for picloram, EPA will proceed with the registration review process and issue the picloram ID.  

The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) requires EPA to periodically review pesticides to ensure that risk assessments reflect the best available science. The proposed interim decision and interim decisions are part of a multi-step process to identify risks as well as actions that can mitigate risks.” 

NALP staff engaged with both EPA and USDA scientists in crafting this decision, offering commentary and advice on how these herbicides are used by lawn and landscape companies across the United States to fill both data gaps as well as features and benefits these products bring to maintaining healthy landscapes in an environmentally sound manner. An example of how this kind of engagement supports industry is seen in this exchange taken from the triclopyr interim decision: 

Comment Submitted by National Association of Landscape Professionals: 

Comment: The National Association of Landscape Professionals state the importance of triclopyr to the lawn care and landscaping business. NALP states that turf uses of triclopyr are unlikely to result in exposure to pollinators since the application of triclopyr to turf is intended to keep blooming weeds from proliferating. NALP also notes that there have been no compost contamination incidents for triclopyr products and that professional landscapers do not use grass clippings as mulch. Due to EPA’s concerns for pollinators and compost contamination, NALP sees the need for the development and adoption of best management practices for triclopyr use (or even pyridines generally) in lawn and landscape settings to educate applicators on these issues. 

EPA Response: EPA thanks NALP for their comments on the triclopyr PID. Similar comments related to pollinators were received from Corteva and EPA’s response is provided above. While EPA is not requiring a registrant-generated stewardship plan for triclopyr, the Agency agrees that the education of applicators and land managers on turf best management practices for the pyridine herbicides as a group is important. Education and stewardship efforts are being initiated for other pyridine herbicides with compost contamination concerns. As additional education or stewardship materials related to compost concerns are made available, EPA will continue to encourage the distribution of those resources to other stakeholders

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