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New Herbicide Threatens to Contaminate Compost

May 25, 2011

(Ronkonkoma, NY – May 25, 2011) The U.S. Composting Council (USCC) is warning composters to watch out for grass clippings contaminated with a new herbicide from DuPont.  Imprelis has been registered in every state except California and New York for use by licensed applicators on lawns and other turf areas for control of broadleaf weeds like dandelion, clover and plantain. The label clearly states that clippings from treated grass should not be used as mulch or put in a compost pile.

“One problem is that the warning is on page 7 of a 9 page label,” remarked Dr. Stuart Buckner, Executive Director of the USCC, “and unfortunately not everyone reads or follows the label. We are requesting the USEPA initiate a special review of the registration due to the likelihood of residual herbicide levels in compost damaging non-target plants.”

The USCC is informing the composting industry and consumers that grass from treated lawns could end up in a compost pile, and unlike most herbicides, Imprelis will survive the composting process and still be active in the finished compost. Preliminary research has shown that Imprelis does not break down significantly faster than the leaves and grass in the compost, so the concentration stays about the same.  An unsuspecting gardener using contaminated compost could end up damaging their flowers and vegetables, most of which are also broad-leafed.

Currently, it is unlikely that municipal or commercial compost will contain significant amounts of Imprelis, though it is possible in suburban areas where a large amount of clippings could come from commercially treated lawns.  It could especially be an issue for places like schools, recreational fields or golf courses that use their grass clippings to make compost and then use the compost in landscape beds or gardens instead of on turf.

“We are alerting our members to this issue, that they need to make sure their haulers are informed to not bring them grass clippings that have been treated with Imprelis,” continued Buckner. “We also suggest they work with their state’s bureau of pesticide applicator licenses to ensure applicators know about this restriction.  We have reprinted Dupont’s special applicator notice on the back of our Composter Alert.” To view the Composter Alert, click here.

The US Composting Council is a Trade and Professional Organization dedicated to the development, education and promotion of the Composting industry.

For more information, contact:
Stuart Buckner, Executive Director
U.S Composting Council

USCC Imprelis Press Release
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