Thousand Cankers Disease (TCD) of black walnut was found in central Virginia along I-95 in 2011, and later that year in Bucks County, PA. TCD is a disease of walnut trees, Juglans spp., and it has continued to spread east in the last few years, after initial finds in the Western U.S. and Tennessee. The causal fungus is carried by the very tiny walnut twig beetle. Small cankers form under the bark of the tree, and ultimately trees die. Yellowing and dieback in the tops of trees are usually the first symptoms. Native black walnuts in Delaware are at risk.
Contact the UD Plant Diagnostic Clinic for information.151 Townsend Hall, 531 South College Avenue, Newark, DE. (302) 831-1390.