Imprelis Update

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Posted on August 8th, 2011 by Kerry Richards in Applicators

This week’s guest blogger is Kerry Richards, our Program’s Director. Kerry has been following the Imprelis issue very closely over the past month.

Dupont’s Imprelis® herbicide is labeled to control broadleaf weeds in cool grasses and some, but not all, warm season grasses. The Environmental Protection Agency (EPA) accepted the conditional registration of  Imprelis® for sale August 31, 2010, and the product was first used in the fall of 2010 without any reported adverse affects.

Now, according to DuPont communications with turf management product distributors on August 5, 2011, they are implementing a voluntary suspension of the sale and distribution of Imprelis®. In addition they will soon be conducting a product return and refund program for Imprelis® from its distributor customers. This decision comes after reports of problems associated with the use of the product which, according to DuPont, are concentrated in a geographic band that includes Minnesota, Michigan, Indiana, Ohio, Pennsylvania, New Jersey, and Wisconsin.   

A severe case of Imprelis injury, where entire trees turned brown and began to lose needles.

In addition to damage that may be caused to trees and shrubs from root update of the product, the use of grass clippings and disposal of trees that may be contain Imprelis® residue is a concern. See Some Observations on Imprelis® Injury to Trees by Pete Landschoot, Professor of Turfgrass Science, Penn State College of Agricultural Sciences.

Grass Clippings:

  • According to the DuPont™ Imprelis® label directions, the use of grass clippings from treated areas in mulch or compost is prohibited.
  • This includes clippings for the ENTIRE summer.
  • Clippings should not be composted, or disposed of in municipal compost of grass clippings.

Replacement and Disposal of Trees:

  • For DuPont™ Imprelis® herbicide treatments applied at labeled rates prior to June 1, 2011 trees can be replanted after October 1, 2011. As an additional precaution, do not use Imprelis® treated soil to back-fill around newly planted trees.
  • For DuPont™ Imprelis® herbicide treatments applied at labeled rates between June 1, 2011 and June 30, 2011 trees can be replanted after November 1, 2011. As an additional precaution, do not use Imprelis® treated soil to back-fill around newly planted trees.
  • As a precaution, if the property was treated with Imprelis®, and a tree has been cut down, do not chip the tree for use in mulch or compost.

Additional communication from DuPont indicates that the company is requesting to be notified of concerns or issues with the use of this product. DuPont has indicated that to make it easier to report problems and have them resolved as quickly as possible, they have:

  • Engaged 20 independent, certified arborist companies to work with you and evaluate your claim.
  • Launched a website:, to carry the latest information about Imprelis® and to make it easier for problems to be reported.
  • Established a toll free hotline (866-796-4783) to take all reports of problems from lawn care professionals, property managers and owners, and golf courses, and to handle any questions and concerns. The number is not for the purpose of filing claims, but rather for the purpose of gathering information for their investigations.

The following photos were taken by Andy Beck, Penn State Extension Educator in Schuylkill County.

Herbicide Damage.

Herbicide Damage.

Herbicide Damage.

For additional images, see: Images of Herbicide Injury to Trees

Until Next Time,
Be Safe



EPA/Dupont Communications:

DuPont Website: The Facts about Imprelis and some Dupont Communications are posted at Letters and Statements.
Additional DuPont communications have been received via direct email.

Jonathan Stempel. DuPont to Recall, Stop Selling Herbicide. Reuters article. August 4, 2011.