Skip to content

Thousand Cankers Disease

All materials needed in another accessible format can be made available upon request.

Walnut Twig Beetle

Thousand cankers is a recently recognized disease of certain walnuts (Juglans spp.). The disease results from the combined activity of the walnut twig beetle (Pityophthorus juglandis) and a canker producing fungus in the genus Geosmithia (proposed name Geosmithia morbida). At present (2009) the disease is 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.

This disease was first recognized and described in 2008 by Ned Tisserat and Whitney Cranshaw of the Department of Agricultural Biology.

Tisserat, N., W. Cranshaw, D. Leatherman, C. Utley, and K. Alexander. 2009. Black walnut mortality caused by the walnut twig beetle and thousand cankers disease. Plant Health Progress. August 11, 2009. 10 pp. (This is the original description of the disease in a peer reviewed journal.)

Thousand Cankers Disease: An Unusual Paradigm – June 2011, American Nurseryman

Thousand Cankers Disease Poster


Fact Sheets:

Questions and Answers about Thousand Cankers Disease of Walnut

Pest Alert – Walnut Twig Beetle and Thousand Cankers Disease of Black Walnut

Diagnosing Thousand Cankers Disease of Walnut

Method for Isolating and Maintaining Cultures of Geosmithia from Juglans nigra.



Thousand Cankers Disease Annotated Bibliography 12.15


PowerPoint Presentations on Thousand Cankers Disease / Walnut Twig Beetle Walnut in the West:

Thousand Cankers Disease: Overview and Origins. Whitney Cranshaw. Presented in Charlottesville, VA in July 2012 at the Southern Forest Insects Work Conference

Diagnosing Thousand Cankers Disease. Ned Tisserat May 2011

Thousand Cankers Disease – Annapolis. Ned Tisserat. January 2011

Nightmare on Walnut Street: Thousand Cankers Disease as an Emergent Threat to Juglans. Whitney Cranshaw. Presented at the International Society of Arboriculture Conference, Chicago, IL July 27, 2010

Walnut in the West: Death by a Thousand Cankers. Ned Tisserat. July 21, 2010

Issues Surrounding Thousand Cankers Disease and Its Management. Whitney Cranshaw. Presented at the First Conference on Thousand Cankers of Walnut, St. Louis, MO November 3, 2009

Contact CSU Equal Opportunity Privacy Statement Disclaimer

2018 Colorado State University, Fort Collins, Colorado 80523 USA