Imprelis ® Damage to Trees Primer

1. Imprelis® Damage to Trees Primer

2. What is Imprelis®? • A Broadleaf Herbicide for Turf and Right-of-way Use • Introduced by DuPont in Spring, 2011 • Active Ingredient: aminocyclopyrachlor

3. Why Imprelis® Turf Magazine - November, 2010 TURF SCIENCE New Products “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.”

4. How does Imprelis® Work? 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. Imprelis® related to Clopyralid • Clopyralidintroduced. . . as a broadleaf herbicide. • Clopyralid found in organics waste stream. • Decomposition processes in compost...did not degrade the molecule. • Compost was herbicidal.

6. Imprelis® • Long residual -- not biodegradable • High concentrations remain in plants • Herbicidal at very low concentrations • Recycled in grass clippings and tree leaves • Evergreen & deciduous plants affected

7. What Did DuPont Do? • Introduced by DuPont in Spring, 2011 • By June, 2011, damage to trees and shrubs was reported... • By end of summer 2011, Imprelis® was pulled from use

8. What plants are affected? • All woody trees, shrubs, vines • Damages new growth • Spruce, honey locust, cottonwood are especially sensitive

9. Symptoms of Imprelis® Damage • Dead buds, shoots, pine candles • Twisted, fused needles • Contorted, chloroticleaves • Tumorous growths on twigs, stems • Twisted, “stretched” twig growth • Death

10. Symptoms of Imprelis® Damage Colorado Spruce dieback, galls, stem swelling

11. Symptoms of Imprelis® Damage Colorado Spruce fused needles

12. Symptoms of Imprelis® Damage Black Hills Spruce

13. Symptoms of Imprelis® Damage Twisted growth Norway Spruce - death

14. Symptoms of Imprelis® Damage White Pine: 2011 on the left, 2012 on the right

15. Symptoms of Imprelis® Damage Needle death, swollen twigs, galls, distorted needles White Pine

16. Symptoms of Imprelis® Damage Northern White Cedar needle & twig death stunted growth, galls

17. Symptoms of Imprelis® Damage Leaf distortion, dieback, similar to plant bug infestation Honeylocust

18. Symptoms of Imprelis® Damage Honeylocust Galls on twigs, branches and stems

19. Symptoms of Imprelis® Damage Ginkgo

20. Symptoms of Imprelis® Damage Freeman Maple Distorted terminal growth

21. Symptoms of Imprelis® Damage Cottonwood Leaf distortion Tip dieback Death of big toothed aspen

22. Mitigation Measures • Prune and remove damaged growth • Chemical moves with water • . . . water moves down-hill

23. Mitigation Measures • Remove all contaminated materials • Including grass clippings, leaves, wood and other plant debris until at least 2014 • Burn or landfill affected yard waste • For replacement plantings • Remove and replace contaminated soil • Amend edges of excavation site with activated carbon

24. Compensation for Tree Loss? • Carefully document all damage: • Maintenance records • Dates • Photos • Symtomology • DuPont claim site: www.imprelis-facts.com • Only through 2013

25. For More Information • Imprelis® Update: 2012 Field Notes on Injury and Recovery. www.ppdl.purdue.edu. • A Turf Professional’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape. www.ppdl.purdue.edu/PPDL/pubs/briefs/ImprelisLCO.pdf • MDA: raymond.pigati@state.mn.us

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