Walnut tree products such as firewood and nuts cannot be moved out of counties across most of eastern Tennessee because of a tree-killing ailment called thousand cankers disease that is being spread by walnut twig beetles.
The beetles have been discovered in Marion County, making it the western-most of the state's counties added to a growing list of buffer-regulated counties surrounding nine counties that are already under quarantine, according to the state Department of Agriculture and the state Division of Forestry.
Walnut twig beetles transmit the thousand cankers disease from tree to tree.
WHAT IT MEANS
Quarantined areas: In counties where thousand cankers disease has been found, a quarantine requires people not to move walnut tree products and hardwood firewood outside of those counties.Buffer-regulated areas: People in buffer-regulated counties can move walnut tree products and hardwood firewood within buffer counties but not outside them. Products can also be moved to a quarantine county, but not taken back out, according to the Tennessee Department of Agriculture. An online symptoms checklist can be found at www.tn.gov/agriculture/regulatory/tcd.shtml.
Forestry and agriculture officials say no walnut products should be transported within the state and none should be brought in from outside the state.
"We will continue to survey for the walnut twig beetle and thousand cankers disease to help slow the spread of the disease," thousand cankers disease plant certification administrator Gray Haun said. "We are working with stakeholders to help educate citizens on the symptoms of TCD and how they can help."
A year ago, the state Department of Agriculture announced that the disease had been found in Morgan and Rhea counties -- which were quarantined -- and had established Hamilton, Bledsoe, Cumberland, Fentress and Meigs counties as buffer-regulated counties, meaning people in those counties cannot move walnut tree products out of them.
Now, the quarantined counties have grown to include Loudon, Blount, Knox, Sevier, Jefferson, Morgan, Anderson and Union counties. And, the buffer-regulated counties have expanded across all of East Tennessee except for seven counties in the extreme northeastern tip of the state.
Thousand cankers disease is a progressive disease that may kill a tree within two to three years after initial symptoms are detected, according to officials.
The fungus Geosmithia morbida, the cause of the disease, is transmitted by the beetles.
The tissues of walnut trees' branches and trunks are killed by multiple infections of the fungus as the insects carry it from one area to another, according to the Department of Agriculture website.
State officials estimate that 1.38 million black walnut trees in urban areas of Tennessee are potentially at risk. That 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 with a value as high as $1.47 billion, state officials said.
Tennessee residents and visitors are asked to take precautions when it comes to handling or using walnut.
Officials say people shouldn't transport firewood, bring firewood with them to Tennessee for camping trips or bring wood from home for camping. People should ask about the source of any firewood they buy, and Tennesseans are warned not to buy firewood out of state.
Anyone who suspects that the disease is infesting black walnuts on their land should call 800-628-2631.
Contact staff writer Ben Benton at bbenton@timesfreepress.com or twitter.com/BenBenton or www.facebook.com/ben.benton1 or 423-757-6569.