Thousand Cankers Disease on Walnut
Branch samples from dying black walnut trees were sent to the Penn State Plant Disease Clinic based on recommendations from Bucks County Cooperative Extension. Initial observations revealed that the trees could be infected with Thousand Cankers Disease. Images of beetles found on the sample were sent to Greg Hoover, Department of Entomology, and he was able to verify that the beetles appeared to be the walnut twig beetle, Pityophthorus juglandis. The Pennsylvania Department of Agriculture (PDA) was contacted and PDA and USDA confirmed the presence of Geosmithia morbida, the fungus that causes the disease, and the walnut twig beetle, which carries the fungus into the trees.
The Pennsylvania Department of Agriculture has established a quarantine in Bucks County. More information can be found on PDA’s Thousand Cankers Disease webpage.
General Fact Sheets and Information
Urban and Rural Forest Disease Management Information
Thousand Cankers Disease Management in Urban Forestry by Whitney Cranshaw