Walnut Twig Beetle

thousand canker disease damage caused by the walnut twig beetle
Pityophthorus juglandis
Last updated by:

Leigh Greenwood


Thousand canker disease is caused by a previously unknown fungus Geosmithia morbida that is carried from tree to tree primarily by the walnut twig beetle (Pityophthorus juglandis). This beetle is native to the Southwestern United States and neighboring Mexico, where it feeds on twigs of Arizona walnut (J. major).

For full information on this pest-fungal complex, please visit our Gallery of Pests page discussing Thousand cankers disease.