Revised quarantine will better protect walnut trees from devastating effects

For immediate release: January 8, 2018 Media contact: Jennifer Holton,  517-284-5724 Program contact: Mike Bryan, 517-284-5648

LANSING – The Michigan Department of Agriculture and Rural Development today announced a revision to the state’s Thousand Cankers Disease of Walnut Quarantine to better protect the state’s walnut trees. The quarantine generally prohibits the shipment of walnut nursery stock, certain walnut timber products and hardwood firewood into Michigan from infested states. Walnut furniture, veneer, kiln-dried walnut lumber without bark and walnut nuts and nutmeats are exempt.

“MDARD is working to prevent loss of walnut resources. Black walnut trees are a vital source of lumber and veneer used in the wood products industries, and makes some of the finest quality timber products in the world,” said Gina Alessandri, MDARD’s Pesticide and Plant Pest Management Division Director. “If Thousand Cankers Disease were to become widespread in Michigan, it could cause significant losses to the state’s walnut timber and nut producing industries. This quarantine will help keep the disease, and the walnut twig beetle that carries the disease, from entering the state.”

This disease has caused significant tree death in the western United States; and, according to the USDA Forest Service there are over eight million black walnut trees in Michigan. Hundreds of walnut trees died in Colorado cities when TCD invaded that state. Almost all black walnut street trees are now gone from Boulder and Colorado Springs, where it was first reported in 2001. Early symptoms of TCD include a yellowing and thinning of leaves in the crown, followed by twig and branch dieback. As the disease progresses, larger branches and limbs are affected. 

The revised quarantine supersedes Michigan’s Thousand Cankers Disease of Walnut Quarantine implemented in 2010.  The updated quarantine reflects new location information on where the disease has been found in North America. TCD is known to occur in Arizona, California, Colorado, Idaho, Maryland, Nevada, New Mexico, North Carolina, Ohio, Oregon, Pennsylvania, Tennessee, Utah, Virginia and Washington. The revised quarantine includes an updated list of regulated areas and a new treatment provision for walnut timber products with bark attached, including hardwood firewood, when those products originate from infested states.

Additional information about the Thousand Cankers Disease of Walnut quarantine is available at http://www.michigan.gov/mdard.

For more information on TCD visit the following websites: http://michigan.gov/exoticpests;  http://www.michigan.gov/invasivespecies; http://thousandcankers.com/

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