Thousand Cankers Black Walnut Disease is Coming Our Way

Adding to the already long list of non-native diseases and insect pests affecting our eastern hardwood forests is a new one in our area, Thousand Cankers Disease, which affects walnuts (Jugus spp.) The disease is caused by a fungus, but it is introduced to new trees by the walnut twig beetle (Pityophthorus juglandis). Thousand Cankers Disease is now widespread in the western United States, but has only recently been found to have spread east of the Mississippi. In June 2011, the disease was identified for the first time in Virginia, in two trees in Chesterfield County. As a result, the Virginia Department of Agriculture and Consumer Services instituted a temporary quarantine to help prevent the spread of this disease to other areas of the Commonwealth. Black walnut trees and tree parts (such as mulch, firewood, and wood chips) cannot be moved out of Chesterfield County, Goochland County, Hanover County, Henrico County, Powhatan County, or the cities of Richmond and Colonial Heights.

Virginia Master Naturalist volunteers and other members of the public can help with these efforts by staying on the lookout for walnuts with Thousand Cankers Disease in their areas. Learn to recognize the field signs and symptoms, and if you suspect your black walnut tree may have thousand cankers disease, contact your local county Extension agent for more information on submitting a plant sample to the Virginia Tech Plant Disease Clinic for diagnosis. A You Tube video provides helpful images for identifying suspect trees, and more information is available from Virginia Cooperative Extension and VDACS.

Another way that everyone can help slow the spread of forest pests and pathogens and help prevent the introduction of new ones is to avoid moving firewood. The Don't Move Firewood campaign has great educational resources for both youth and adults.