A west coast disease that destroys trees has been detected for the first time in Pennsylvania and state Agriculture officials have announced a quarantine to stop any spread. The disease is caused by a beetle.
The Walnut Twig Beetle tunnels beneath the bark of black walnut trees, carrying a fungus that causes small cankers or lesions to form on the tree. As more beetles attack and the number of cankers increases, the tree is slowly starved of nutrients and dies, thus the name Thousand Cankers Disease.
Sven-Erik Spichiger, entomology program manager for the state Agriculture Department, says it poses a significant threat to the hardwoods industry. He says black walnut is a high value timber tree in Pennsylvania. He says many people also use the trees in landscaping.
The disease has been detected in Plumstead Township, Bucks County. The quarantine restricts the movement of all walnut material, whether it’s living, cut, chipped or dead, as well as all hardwood firewood from Bucks County and other states known to have the disease. It does not apply to nuts, processed lumber or finished wood products without bark. Failure to follow the quarantine could result in criminal or civil penalties.
There’s no known control or cure for Thousand Cankers Disease. Spichiger says people who see signs of the disease should report it to the department’s pest hot line at 1-866-253-7189. Symptoms start with die back in the upper crown, with areas losing leaves or leaves turning yellow. The beetle makes very tiny holes in the tree, about the size of a poppy seed, so it’s usually hard to detect.