Thousand Cankers Disease on Walnut

A newly recognized disease on black walnut trees called Thousand Cankers Disease (TCD) has been detected in Pennsylvania.

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

Penn State Fact Sheet

Frequently Asked Questions (Tennessee Department of Agriculture)

Urban and Rural Forest Disease Management Information

Thousand Cankers Disease Management in Urban Forestry by Whitney Cranshaw

If you Suspect Thousand Cankers Disease

If you suspect symptoms of Thousand Cankers Disease please contact your County Extension Office or the Invasive Species Hotline at 1-866-253-7189 or