COLUMBIA — Of the 15 white pines, 13 were damaged.
Some showed only slight browning on upper branches, but on others, all new growth on every branch tip was completely curled and browned.
Just two of the trees appeared unharmed.
Chris Starbuck, the MU Extension state woody ornamentals specialist, examined the trees and said he believes the culprit was Imprelis, a DuPont herbicide used for weed control.
Starbuck said he'd seen at least 24 sites in Columbia that had damaged trees and shrubbery. He could not identify the locations of the damaged trees due to privacy concerns.
Now, Starbuck is helping landscaping companies and homeowners gather information about the effects of Imprelis and decide how to handle the damage.
Imprelis was labeled in the fall of 2010 and made available to professional lawn care companies this past spring, Starbuck said. Imprelis is being blamed for the death of eastern white pines and Norway spruce trees across the nation, according to an Environmental Protection Agency press release.
At first, Imprelis seemed like a dream product. It carries low risk for animals and people, and it only takes 4 ounces to treat an acre of land.
"It's one of the best herbicides to come along in a long time," Starbuck said. "I don't think you could argue with the fact that it is environmentally friendly — except to trees."
But DuPont suspended sales of Imprelis on Aug. 4 after the EPA issued an order under the Federal Insecticide, Fungicide and Rodenticide Act because a large number of trees had been harmed by the herbicide. The EPA launched an investigation to determine whether the cause of the problem was product misuse, inadequate warning labels or other environmental factors.
Starbuck has his own ideas about why there are problems with Imprelis. The reason it’s so effective is because it penetrates soil to be taken up by roots of weeds. Consequently, it’s also able to enter the extensive root systems of older trees. And because DuPont products are often tested on turf plots with no trees around, the negative effects most likely went undetected, Starbuck said.
Dan Hankins, a certified arborist and operations manager at Braik Brothers Tree Care and Green Waste Recycling, said he’s encountered at least one case where trees and shrubs were damaged after Imprelis was used.
“They would just mysteriously die, young trees or older trees," he said.
After sending soil tests to a lab at MU, Hankins called the lawn-care company that treated the grass and found Imprelis was used on the job. Then, he learned more about its effects.
"It wouldn't surprise me if there were some other trees from other jobs that I'd looked at — trees that were already dead or had died out that were caused by it,” Hankins said. “I'd put it more on that than on any other factor."
Six Columbia landscaping companies were contacted and all said they did not use Imprelis or did not wish to be included in the article.
Starbuck said several companies and Columbia homeowners who experienced damage from Imprelis are involved in conversations with DuPont about legal issues, insurance and compensation.
DuPont plans to start a product return and refunds program, according to the EPA, but that is for the cost of the herbicide. Starbuck said he isn't sure how reimbursement for lost trees will work, since it's difficult to assign value to plants, and there aren't many people who are qualified to do so.
Even so, Starbuck said compensation could reach into hundreds of thousands of dollars. He said he expects DuPont might reimburse people by giving them money to purchase the largest transplantable size of the tree they lost.
Starbuck also said he wouldn't be surprised if there were attempts to sue for pain and suffering.
"There really is no replacement of some of these trees. If you have a 30-year-old spruce tree that's dead, you won't see that again in your lifetime," Starbuck said. "It is really sad when you lose large trees on your landscape. Your grandkids may have planted them in your yard, and you have an emotional attachment to them, and there's no amount of compensation that will completely satisfy you there."
Beyond the issue of reimbursement, there are still unanswered questions about Imprelis. Its long-term effects are unknown, as is whether or not plants will recover. And Starbuck said there may be residual effects in the spring.
“In the meantime, people are going have to deal with their situations as best they can,” Starbuck said.