Thousand Cankers Disease Threatening Black Walnut Trees, IAA Reports
Pennsylvania recently became the 12th state to detect Thousand Cankers Disease (TCD) in its trees. increasing the threat to black walnut trees from coast-to-coast. The negative impact on several industries could be severe.
TCD dates back to the 1990s though had been limited to the western United States until recent reported infestations in Tennessee, Virginia and Pennsylvania. The disease is caused when fungus-carrying Walnut Twig Beetles tunnel beneath the bark of walnut trees, allowing small cankers to form. As more beetles attack the tree, the number of cankers increases. The tree is slowly starved of nutrients, causing the tree to die within 10 years of initial infestation. There is no known cure.
Illinois neighbors Indiana, Missouri and Wisconsin have enacted quarantines on walnut nursery stock and raw wood. To date, Illinois has not followed suit. As with Emerald Ash Borer – which communities across Illinois continue to fight – IAA President Mark Younger says TCD-damaged trees provide an economic hardship on home owners, neighborhoods and communities.
“The loss of urban forests and the positive benefits trees provide would be an initial impact,” Younger said. “But the economic impact on businesses, the homeowners’ expense removing and replacing trees, and added budget costs for communities in a challenging economy also add up.”
Certified Arborist Guy Sternberg of Starhill Forest Arboretum in Petersburg, Ill., advocates a quarantine sooner rather than later.
“There is a need for an external quarantine, and that need grows with each TCD finding like we are seeing in other states,” he said. “After working 32 years at the Department of Natural Resources I believe we must be forceful and proactive to protect the trees, the property and livelihoods of rural landowners, hunters, naturalists and the walnut industry.”
Many species of wood-boring insects, including those carrying TCD and EAB, can be spread by transporting infested firewood and logs. Campers, in particular, are encouraged to use only locally harvested firewood, burn all of it on-site and never transport firewood to a new location.
Illinois Arborist Association background
The Illinois Arborist Association is a non-profit organization that educates members and the general public in proper tree care. IAA supports research on trees and is based on the mission to "Foster interest, establish standards, exchange professional ideas and pursue scientific research in Arboriculture."