Potential Damage From Imprelis® Herbicide
What is Imprelis?
Imprelis® is a new herbicide from Dupont™ for broadleaf weed control in lawns and turf and is used by professional lawn and landscape businesses. Unfortunately, there are reports of damage to conifers that appears to be related to the use of Imprelis. In particular, Norway spruce and white pine seem to have received the most severe damage. However, there have been unsubstantiated reports of damage to ornamental plants, shrubs and oak trees.
The active ingredient in Imprelis is aminocyclopyrachlor.
Damage to white pines includes twisting and curling of this year’s needles. For spruce trees, the damage appears to be the browning of individual needles at the tips, yellowing (chlorosis) of needles at the base and chlorosis of the newly forming branches.
The damage to individual trees varies from minor to fairly extreme and trees immediately adjacent to affected trees may not show symptoms. The damage appears about 4-6 weeks following an application of the product.
The University of Wisconsin Extension has created a fact sheet with photographic examples.
Imprelis Fact Sheet – 2 page PDF
If You Suspect Imprelis Damage
: As of September 6, 2011, DuPont has developed a claims resolution process. Homeowners, property managers, golf course superintendents, etc., should contact their professional lawn and landscape business. You can find futher details at this DuPont website
DuPont, the manufacturer of Imprelis is looking into the problem and trying to determine the cause of the damage and if other variables might be involved.
DuPont has created a website to share information for landscape professionals and homeowners at
DuPont also has a toll-free hotline to report damage and to ask questions. That number is 866-796-4783.
DuPont is recommending that the lawn and landscape industry halt applications of Imprelis to properties where Norway spruce and white pine are present or nearby.
In the meantime, property owners who suspect tree damage may be caused by an application of Imprelis should do the following:
- Contact the business that provided the lawn service to your property.
Determine if the business applied Imprelis. You should also find this information on pesticide application information that the company provided you at the time of application.
Take photographs of damage that you observe
Take samples of branches or plant material that show visible damage as well as samples that do not show damage from the same tree or plant.
Place these samples in plastic bags or containers and freeze them. If further laboratory tests are needed, the samples will be available.
If you intend to have the plant material tested in the near future, (by the University of Wisconsin Plant Disease Diagnostic Clinic http://pddc.wisc.edu for example) the samples can be refrigerated.
Mark samples with the dates they were collected. If you take samples from multiple trees or plants, keep them separated and identify the samples.
Keep records of phone calls, paperwork and photographs.
Information for Professionals
Update As of September 6, 2011, DuPont has started a claims resolution process. Further details are available on this web page created by DuPont.
UpdateAs of August 11, 2011, the Environmental Protection Agency issued an order to DuPont directing the company to immediately stop the sale, use or distribution of Imprelis herbicide.
As of August 4, 2011, DuPont announced a voluntary suspension of Imprelis herbicide. The company is developing a product return and refund program. DuPont intends to start the return and refund program in mid-August. the program will cover full, partial and all pack sizes of Imprelis. More details will be announced. For immediate questions, call DuPont's Customer Service at 1-800-342-5247 (prompt 99.)
Check DuPont's website created for the Imprelis issue at http://www.imprelis-facts.com
. The toll-free hotline is also available at 866-796-4783 to report damage and ask questions.
Caring for Damaged Conifers
It is recommended that damaged trees not be trimmed or fertilized at this time but keep them watered to reduce stress. The University of Wisconsin-Extension and the UW-Madison Department of Horticulture have created a 2 page fact sheet that covers possible Imprelis herbicide damage for conifers and recommended care.
DuPont also created a fact sheet on caring for stressed trees.
Grass Clippings - Property owners are reminded: do not use grass clippings from Imprelis-treated areas for mulching or compost, and do not send to a composting facility. Grass clippings must be left on the treated area. The product appears to be long-lasting in the grass clippings. Using the clippings on a garden could harm the garden plants. Clippings taken from lawns treated with Imprelis could harm other plants if the clippings are piled on, under or near other trees or shrubs.
The United States Composting Council (USCC) has issued a composting alert.
Wood Chips or Mulch - If a damaged or dead tree is removed and chipped, do not use the chips as mulch or bark. Again, Imprelis appears to be long-lasting and could potentially remain in the chips or mulch which could then cause harm to other plants.
Other Causes for Damage
It is possible that the damage to Norway spruce, white pines, ornamental plants, shrubs or trees could be caused by plant diseases, insects or other factors.
You may wish to contact a certified arborist at the Wisconsin Arborists Association http://www.waa-isa.org/.
If you would like to have your trees or plants examined, contact the Plant Disease Diagnostic Clinic at the University of Wisconsin Madison at http://pddc.wisc.edu or call 608-262-2863 or send an email to email@example.com.
The UW-Madison Turfgrass Diagnostic Lab may also be a resource. Their web site is http://www.tdl.wisc.edu or call (608) 845-2535.
United States Environmental Protection Agency (EPA) has launched a website with information on their investigation in the damage reports associated with the use of Imprelis.