DuPont herbicide linked to tree damage

UPPER UWCHLAN – About 300 trees in the Marsh Harbour neighborhood are damaged or dying, and the suspected culprit is the herbicide Imprelis.

“It’s a shame that it happened anywhere but especially upsetting here,” said Vince McVeigh, president of the Marsh Harbour Homeowners Association. “We have beautiful, full trees, and it certainly has changed our look.”

Next to Marsh Creek State Park, Marsh Harbour is one of many areas nationwide with sudden damage to Norway spruces, white pines and Colorado Blue spruces traced to Imprelis, a weed-killer manufactured by DuPont Professional Products.

The U.S. Environmental Protection Agency conditionally approved Imprelis in August 2010. It is manufactured to target broadleaf weeds, such as dandelions, clover and ground ivy. And it is considered less toxic than older herbicides such as the commonly used 2,4-D.

Peter Lanscoot, a professor of turf-grass science at Pennsylvania State University, said the new herbicide has lower toxicity for animals and humans than its predecessors.

“But that doesn’t mean it’s not very active on plants,” Lanscoot said.

The active ingredient in Imprelis is aminocyclopyrachlor, which is absorbed by the weeds’ roots, although Lanscoot said tree damage indicates the chemical is taken up by tree roots, too, then transported through to areas of new growth, such as branches with developing or newly developed needles.

According to McVeigh, the community’s contracted landscaping company applied Imprelis in early April, and the nearby trees began to turn a sickly shade of brown in May.

“Shortly after that we learned this was happening in other places,” he said. “From that point on, we’ve been working with our (landscaping) company to address the problem.”

Lanscoot said unusually heavy rainfall coinciding with the April and May applications of the product may have contributed to the extent of the local damage.

“(It) may have resulted in some leaching that wouldn’t have ordinarily occurred,” Lanscoot said. “Some of it may have washed down into the root zone.”

Browning and dying trees have been reported from New Jersey to as far west as Iowa and as far south as Georgia. The damage has varied from just the tips of branches to entire evergreens turning brown.

The widespread nature of the effects has provoked lawsuits and an investigation by the EPA and DuPont.

On July 27 DuPont issued a letter to landscapers admitting Imprelis caused the damage and apologizing for that damage while maintaining that most areas treated with its product displayed effective weed control without reported tree damage.

The company also hired 20 independent arborist companies to assess the damage and resolve customers’ claims. And DuPont has launched a Web site,, and set up a hotline to handle reports about the weed-killer.

“DuPont is committed to proper stewardship of all its products,” said company spokeswoman Kate Childress. “We are working with our customers to investigate reports of unfavorable symptoms on certain tree species.”

While Marsh Harbour has tallied the number of damaged trees up to at least 100, McVeigh said the association’s board is still deciding its next move and is discussing options, including a lawsuit.

“We have to try to react prudently,” McVeigh said. “I’m sure the damage is certainly in excess of $1 million, perhaps closer to $2 million. A lot will depend on the final remediation plan. Our goal, as a board, is to make sure that our residents’ money is not used in those payments of damage.”

McVeigh said he and the other board members are also looking at reconstructing the landscaping while working with their landscaping company, Land-Tech.

“We’ve learned so far that we’re not going to plant trees this year,” McVeigh said. “We will remove trees in the near future. The ones near homes we’ll bring down right away.”


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