1. Minnesota First Detectors Imprelis® Damage to Trees Primer University of Minnesota Extension Minnesota Department of Agriculture

2. Minnesota First Detectors What is Imprelis® What Does it Do? A Broad-leaved Herbicide for Turf Use Introduced by DuPont in Spring, 2011 Active Ingredient: aminocyclopyrachlor

3. Minnesota First Detectors What is Imprelis® What Does it Do? “Control Weeds Even on Rainy Days DuPont Imprelis herbicide...control dandelion, clover and plantains, as well as tough broadleaf weeds...even during reseeding or rainy days...a low application rate... and is the first compound in an advanced generation of herbicides. Turf Magazine - November, 2010 TURF SCIENCE New Products

4. Minnesota First Detectors What is Imprelis® What Does it Do? Turf Magazine - November, 2010 TURF SCIENCE New Products “Imprelis® is readily absorbed by plant leaves and roots, stopping the growth of target weeds by interfering with the hormonal balance necessary for normal shoot and root development.”

5. Minnesota First Detectors What is Imprelis® What Does it Do? Aminocyclopyrachlor & Clopylralid Clopyralid introduced...as a broadleaf herbicide... Clopyralid found in organics waste stream... Decomposition processes in compost...did not degrade the molecule. Compost was herbicidal.

6. Minnesota First Detectors What is Imprelis® What Does it Do? Similar to Clopyralid: Long residual Not biodegradable High concentrations remained in plants Herbicidal impacts at very low concentrations Recycled in grass clippings/Tree leaves

7. Minnesota First Detectors What Did DuPont Do? By June, 2011, damage to trees and shrubs was reported... By end of summer, Imprelis® was pulled from use

8. Minnesota First Detectors Symptoms of Imprelis® Damage Evergreen and deciduous... Dead buds, shoots, pine candles... Twisted, fused needles... Contorted, chlorotic leaves... Tumorous growths on twigs, stems... Twisted, “stretched” twig growth... Death

9. Minnesota First Detectors Symptoms of Imprelis® Damage Colorado Spruce

10. Minnesota First Detectors Symptoms of Imprelis® Damage Colorado Spruce

11. Minnesota First Detectors Symptoms of Imprelis® Damage Black Hills Spruce

12. Minnesota First Detectors Symptoms of Imprelis® Damage Norway Spruce

13. Minnesota First Detectors Symptoms of Imprelis® Damage White Pine: 2011 on the left, 2012 on the right

14. Minnesota First Detectors Symptoms of Imprelis® Damage White Pine

15. Minnesota First Detectors Symptoms of Imprelis® Damage Northern White Cedar

16. Minnesota First Detectors Symptoms of Imprelis® Damage Honeylocust

17. Minnesota First Detectors Symptoms of Imprelis® Damage Honeylocust

18. Minnesota First Detectors Symptoms of Imprelis® Damage Ginkgo

19. Minnesota First Detectors Symptoms of Imprelis® Damage Freeman Maple

20. Minnesota First Detectors Symptoms of Imprelis® Damage Cottonwood

21. Minnesota First Detectors Susceptible Plants? To Date: all woody trees, shrubs, vines

22. Minnesota First Detectors Treatments? Avoidance? Damage is to new growth Prune and remove damaged growth Chemical moves with water...water moves down-hill

23. Minnesota First Detectors Treatments? Avoidance? Remove all contaminated materials Capture and remove grass clippings, leaves, wood and any other plant debris that might be contaminated through at least 2014 Replace contaminated soil As much as you can around the new planting site Amend existing soil remaining around the edges with activated carbon

24. Minnesota First Detectors Compensation for Tree Loss? Carefully document all damage: Maintenance records Dates Photos Symtomology DuPont claim site: www.imprelis-facts.com

25. Minnesota First Detectors For More Information Imprelis® Update: 2012 Field Notes on Injury and Recovery. www.ppdl.purdue.edu.www.ppdl.purdue.edu A Turf Professional’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape. www.ppdl.purdue.edu/PPDL/pubs/briefs/Imprelis LCO.pdf www.ppdl.purdue.edu/PPDL/pubs/briefs/Imprelis LCO.pdf

26. Minnesota First Detectors Acknowledgement All Imprelis® symptoms images were generously shared by: Manuel Jordan: Heritage Shade Tree Consultants and John Lloyd: Plant Health Doctors.com