Thousand Cankers Disease
The Tennessee Department of Agriculture on Friday announced the discovery of Walnut Twig Beetles, which transmit Thousand Cankers Disease (TCD), a walnut tree killing disease in Marion County. The county is now buffer regulated. Citizens in buffer counties can move walnut tree products and hardwood firewood within buffer counties, but not outside. Products can also be moved into a quarantine county, but not taken back out.
In addition to Marion County, Bledsoe, Campbell, Claiborne, Cocke, Cumberland, Fentress, Grainger, Greene, Hamblen, Hamilton, McMinn, Meigs, Monroe, Polk, Roane, Scott, and Sequatchie are also considered buffer regulated counties because the Walnut Twig Beetle was found or they are adjacent to a quarantined county. Bradley County is also in the buffer regulated category because it is surrounded by other buffer regulated counties.
“We will continue to survey for the Walnut Twig Beetle and Thousand Cankers Disease to help slow the spread of the disease,” said TDA Plant Certification administrator Gray Haun. “We are working with stakeholders to help educate citizens on the symptoms of TCD and how they can help.”
TCD is a progressive disease that may kill a tree within two to three years after initial symptoms are detected. The disease-causing fungus, Geosmithia morbida, is transmitted by the Walnut Twig Beetle, Pityophthorus juglandis. Branches and trunk tissue are killed by multiple infections of the fungus as the beetles carry the fungus from one area to the next.
TDA plant inspectors and foresters will continue to conduct a thorough survey of trees in these areas to assess the extent of the infestation and to see if more areas need to be quarantined. Counties already under quarantine for TCD include Anderson, Blount, Jefferson, Knox, Loudon, Morgan, Rhea, Sevier, and Union.
The Tennessee Department of Agriculture Division of Forestry estimates that 1.38 million black walnut trees in Tennessee’s urban areas are potentially at risk from TCD.
The risk represents an estimated value loss of $1.37 billion. There are an estimated 26 million black walnut trees on Tennessee public and private timberland potentially valued as high as $1.47 billion.
TDA officials urge area residents and visitors to help prevent the spread of TCD:
- Don’t transport firewood, even within Tennessee. Don’t bring firewood along for camping trips. Buy the wood you need from a local source. Don’t bring wood home with you.
- Don’t buy or move firewood from outside the state. If someone comes to your door selling firewood, ask them about the source, and don’t buy wood from outside the state.
More information about Thousand Cankers Disease and forest health threats in Tennessee can be found at www.protecttnforests.org.
For more information about other programs and services of the Tennessee Department of Agriculture visit www.tn.gov/agriculture.
Walnut Twig Beetle