DuPont's New Herbicide is Killing More Than Weeds

Have you noticed any of your Pine or Spruce trees turning brown? I did. We have an approximately 25-foot Norway Spruce that was showing, I thought, signs of distress. I figured it was the hot weather so I made sure to water it. It continued to show more brown. It seemed odd — the new growth was still very green but the old growth was turning brown.

I took some pictures of the tree and e-mailed it to my uncle who is a retired arborist for the City of Milwaukee. He said that the pictures really didn't fit any disease or distress that he was familiar with, so he referred me to another tree specialist. Ken, a delightful gentleman with years and years of tree expertise, stopped by my house a week later.

By now the browning of needles had intensified. One look at it and he said that he hates to tell me, but he is certain I have herbicidal poisoning.

"Well, how could that be?" I asked him, and he asked if we use a lawn service. Yes, we do, but I have used the same lawn service for 24 years, and they are great and I have never had a problem before.

That is when he informed me that there is a new product on the market from DuPont called Imprelis that is having negative affects on evergreen trees, in particular, Norway Spruce and White Pines. To my horror, Ken pointed out my three 35-foot Norways in the front yard and said he could see some mild signs of browning on some lower branches of one of the trees.

I contacted my lawn care provider and sure enough, thay had used Imprelis. I had only one application of the product on May 24th.

So what is Imprelis? It is a new selective herbicide intended for use by lawn care professionals. This product was marketed by DuPont to provide control of several difficult to control turf weeds, such as ground ivy and wild violet. It works by both direct uptake through the foliage as well as root uptake and provides good residual control. Aminocyclopyrachlor, the active ingredient in Imprelis, is in a new subclass of herbicide chemistry called the pyrimidine carboxylic acids. It is designed to control broadleaf-weeds in turf by interfering with a plant's normal hormonal balance (auxin). Since this product interferes with auxin, damage from Imprelis is distinctive.

So why would a lawn care service want to use this product? DuPont did a very good job selling the benefits. This product was touted as being safer for people, pets and the environment, while controlling weeds to a higher degree. The owner of my lawn care business met personally with DuPont researcher Dr. Bruce Steward over the winter and after many questions he was convinced that this product was truly the finest available.

He along with other lawn care companies and golf course operators put their trust in DuPont's reputation of expert research and development and now feel sickened and frustrated by the misrepresentation of this product and the devastating impact to their customers. They are currently in contact with not only DuPont but the Department of Agriculture, Trade and Consumer Protection and EPA representatives.

DuPont has been limited in their responses to complaints but recently sent lawn care professionals a letter letting them know that as of August 1 they have established a toll-free hotline to take all reports of problems from lawn care professionals, property managers and owners, and golf courses, and to handle any questions and concerns. At this time a certified class-action lawsuit has yet to be announced.

(Editor's note: Reuters News Service reported Thursday that DuPont said it plans to stop selling and recall Imprelis after customers and several lawsuits complained that the treatment has killed thousands of trees.)

If you notice any problems with your evergreens and have had any broadleaf weed treatments, please contact your lawn care provider or call 1-866-796-4783. You can also visit the Imprelis Facts website.  

Three weeks after the first signs of browning on my tree, my poor Norway Spruce stands brilliant burnt orange. The three trees in the front are gaining more brown needles everyday. I am confident that my lawn care professional will see to it that our trees are replaced, but you can't get back the time it took to grow these trees to their majestic hight.

I hope DuPont does the right thing, as I feel bad that these businesses are burdened with this financial setback especially during these trying economic times.