Minnesota First Detectors Imprelis ® Damage to Trees Primer

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

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

Minnesota First Detectors “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.” How does Imprelis ® Work? Turf Magazine - November, 2010 TURF SCIENCE New Products

Minnesota First Detectors Clopyralid introduced... as a broadleaf herbicide. Clopyralid found in organics waste stream. Decomposition processes in compost...did not degrade the molecule. Compost was herbicidal. Imprelis ® related to Clopyralid

Minnesota First Detectors Imprelis ® Long residual -- not biodegradable High concentrations remain in plants Herbicidal at very low concentrations Recycled in grass clippings and tree leaves Chemical moves with water Evergreen & deciduous plants affected

Minnesota First Detectors Higher water solubility: > 30 ppm ( solubility of an herbicide in room temperature water) Longer soil half life: > 21 days time (time required for herbicide to degrade to ½ of its previous concentration in soil) Lower soil adsorption: K oc < 300 – 500 Adapted from: Becker, R.L., D. Herzfeld, K.R. Ostlie, and E.J. Stamm-Katovich Pesticides: Surface Runoff, Leaching, and Exposure Concerns. Minnesota Extension Service Clean Water Publication AG-BU Red flags for increased leaching potential (K oc = Organic carbon partitioning coefficient)

Minnesota First Detectors Tree Roots How wide are tree root systems? Historically root systems were thought to be under the dripline of trees But now we know root systems can grow to cover an area 2-3 times the width of the dripline.

Minnesota First Detectors Shared root zones When turf grasses, weeds, herbaceous plants, shrubs, and especially trees share space above ground in a landscape, they also share: root space below ground. common points of entry for herbicides

Minnesota First Detectors How many potential herbicide points of entry can you find in these pictures?

Minnesota First Detectors 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

Minnesota First Detectors What plants are affected? All woody trees, shrubs, vines Damages new growth Spruce, honey locust, cottonwood are especially sensitive

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

Minnesota First Detectors Symptoms of Imprelis ® Damage Colorado Spruce dieback, galls, stem swelling

Minnesota First Detectors Symptoms of Imprelis ® Damage Colorado Spruce fused needles

Minnesota First Detectors Symptoms of Imprelis ® Damage Black Hills Spruce

Minnesota First Detectors Symptoms of Imprelis ® Damage Norway Spruce - death Twisted growth

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

Minnesota First Detectors Symptoms of Imprelis ® Damage White Pine Needle death, swollen twigs, galls, distorted needles

Minnesota First Detectors Symptoms of Imprelis ® Damage Northern White Cedar needle & twig death stunted growth, galls

Minnesota First Detectors Symptoms of Imprelis ® Damage Honeylocust Leaf distortion, dieback, similar to plant bug infestation

Minnesota First Detectors Symptoms of Imprelis ® Damage Honeylocust Galls on twigs, branches and stems

Minnesota First Detectors Symptoms of Imprelis ® Damage Ginkgo

Minnesota First Detectors Symptoms of Imprelis ® Damage Freeman Maple Distorted terminal growth

Minnesota First Detectors Symptoms of Imprelis ® Damage Cottonwood Leaf distortion Tip dieback Death of big toothed aspen

Minnesota First Detectors Mitigation Measures Prune & remove damaged growth Remove all contaminated materials Including grass clippings, leaves, wood & other plant debris until at least 2014 Burn or landfill affected yard waste For replacement plantings Avoid planting new trees down slope Remove & replace contaminated soil Amend edges of excavation w/ activated carbon

Minnesota First Detectors Compensation for Tree Loss? Carefully document all damage: Maintenance records Dates Photos Symtomology DuPont claim site: Only through 2013

Minnesota First Detectors For More Information Imprelis® Update: 2012 Field Notes on Injury and Recovery. A Turf Professional’s Guide to Suspected Imprelis® Herbicide Injury in the Landscape. relisLCO.pdf relisLCO.pdf MDA:

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