Friday, September 24, 2010

Quarantine to prevent Thousand Cankers Disease

In response to the detection of Thousand Cankers Disease in Tennessee, the N.C. Department of Agriculture and Consumer Services has executed an exterior quarantine in order to prevent the movement of this disease and the walnut twig beetle into North Carolina. Thousand Cankers Disease is caused by a pathogen that is transmitted by the walnut twig beetle and is most frequently associated with black walnut trees.

“The detection of this disease in Tennessee greatly increases the risk the disease will move into North Carolina,” said Agriculture Commissioner Steve Troxler. “The quarantine prohibits the movement of plant material and other high-risk materials from counties where the disease has been detected in order to protect the black walnut species in our state.”

The N.C. Department of Environment and Natural Resources Division of Forest Resources, NCDA&CS and federal partners will be working to implement comprehensive field surveys for this pest. These surveys will take place in high-priority counties adjacent to the Tennessee infestations. Survey crews will be searching for symptoms of the disease on trees, along with collecting and analyzing suspect samples.

The detection of Thousand Cankers Disease in Tennessee is the first discovery of this pest east of the Mississippi River. Since its initial detection in Knox County, Tenn., officials have confirmed an infestation in Blount County, which borders Swain County, N.C., along with infestations in Anderson and Union counties, Tenn.

The exterior quarantine issued by NCDA&CS prohibits the movement of identified high-risk materials from areas currently known or found to harbor the walnut twig beetle or the fungal pathogen. Typical materials include firewood of any hardwood species; plant and plant parts of the genus Juglans such as walnut trees, including nursery stock, budwood, scionwood or green lumber; and other material living, dead, cut or fallen, including logs, stumps, roots, branches and composted and un-composted chips; or other articles known to present a risk of spread. Presently, the entire states of Arizona, California, Colorado, Idaho, New Mexico, Oregon, Tennessee, Utah and Washington have been confirmed as areas known to be infected by the pathogen and are included in the exterior quarantine.
Exemptions to quarantine are nuts, nut meats, hulls, processed lumber (100 percent bark-free, kiln-dried with square edges) and finished wood products without bark, such as walnut furniture, instruments and gun stocks.

Landowners and homeowners in North Carolina are also strongly encouraged to watch for signs of the Thousand Cankers Disease on black walnut trees. Typical symptoms vary depending on the stage of the disease, but commonly include thinning crowns and yellowing or wilted leaves in the crown, leaves that are smaller than normal and relatively recent dead limbs.

Individuals with suspect trees are encouraged to contact the NCDA&CS Plant Industry Division for a consult by calling 1-800-206-9333 or by e-mail at

Walnut twig beetle image courtesy of

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