Dow pulls California clopyralid registrationINDIANAPOLIS -- In response to initiatives by California regulators, makers of clopyralid-containing herbicides Dow AgroSciences and Riverdale Chemical Company are notifying the U.S. Environmental Protection Agency of changes to product labels that will prohibit future use on California residential lawns.
The companies have also requested lawn care operators and dealers and distributors who offer clopyralid-containing herbicides not to sell or use them on residential lawns in California.
These steps are being taken to address concerns expressed by the California Department of Pesticide Regulations (DPR) and others over reports of trace levels of clopyralid in compost which may damage some sensitive plants (e.g., tomatoes, potatoes, peas, beans and sunflowers), especially when compost is used without properly mixing it with soil.
"We are not aware of any documented cases of damage to sensitive plants in California," said Dr. Bryan L. Stuart, Dow AgroSciences state affairs manager. "We believe this is a problem of misuse, but we want to cooperate with DPR and address this matter expeditiously."
Composting of grass clippings from residential lawns has been identified by state regulators as a primary source of trace level clopyralid residues in compost.
Dow AgroSciences clopyralid herbicides have label restrictions on using compost containing grass clippings treated with the product. But homeowners using professional lawn care services may not have been informed that clopyralid was used or not have known that restrictions apply.
In some California locations, curbside recycling of grass clippings is common practice, and many localities promote composting in response to state laws mandating an ongoing reduction in the amount of waste sent to landfills.
Professionals in the lawn and turf care industry expressed support for the use changes initiated by clopyralid's makers.
"We applaud this step taken by the makers of clopyralid," said Bryan Thompson of Landscape Pest Management in Anaheim, "as an effective means of addressing public concerns while maintaining essential uses of these products."
"California agriculture has a vital need for clopyralid products," said Paul Wenger, vice president of the California Farm Bureau. "We are committing to stewarding these products to ensure their safe and proper use."
Clopyralid is a herbicide used by farmers, foresters, ranchers, golf course managers, parks and recreation professionals and others to control hard-to-manage and invasive weeds. Products containing clopyralid have been on the U.S. market for more than 15 years and have been registered in California since 1997.
In a recent press release (March 27), the California DPR described clopyralid as "a low-toxicity chemical that poses little hazard to people, animals and most vegetation."