Thousand Cankers Disease, Missouri Agriculture Image
Thousand cankers disease (TCD) is a newly discovered disease of walnuts including black walnut. The disease results from the walnut twig beetle (Pityophthorus juglandis) hosting a canker producing fungus of the genus Geosmithia (proposed name Geosmithia morbida). TCD was thought to be restricted to the western United States where over the past decade it has been involved in several large scale die-offs of walnut, particularly black walnut, Juglans nigra.
Unfortunately, the canker has now been found in eastern Tennessee in Knox County where there is now a firewood and black walnut quarantine. According to one University of Colorado entomologist, a developing colony of TCD "could very possibly develop into an uncontrollable outbreak" and which could "potentially destroy black walnut in its native range". Not good news for black walnut owners.