Black Walnut - Thousand Cankers Disease (TCD) Confirmed in Ohio by Ohio Department of Agriculture

Aug. 31, 2013

Tuesday, August 13, 2013

Dear Co-Hort:

Thousand Cankers Disease (TCD) of walnut has been confirmed in Butler County, Ohio.  The disease is caused by a fungus (Geosmithia sp.) that is carried from tree to tree by the Walnut Twig Beetle (Pityophthorus juglandis); a type of bark beetle.  Here is a quote from the news release from the Ohio Department of Agriculture (ODA): 

Walnut Twig Beetle was first confirmed in Ohio in late 2012 in traps set by Ohio Department of Natural Resources Division of Forestry officials in Butler County.  Additionally, scientists from the Ohio Plant Diagnostic Network, a cooperative partnership between ODA and The Ohio State University, recently isolated the TCD fungus from walnut branch samples from the Butler County area, marking the first time TCD has been confirmed in Ohio.”

Keep a sharp eye out for the signs and symptoms of TCD on walnut:  chlorotic and wilted leaves, twig and branch dieback, thinning canopy, and epicormic growth.  Unfortunately, the current leaf chlorosis and leaf drop from walnut anthracnose may confuse the issue.  We will have a report on TCD in this week’s Buckeye Yard and Garden Line (BYGL); the online version ( ) will include images.

Pest Alert Factsheet:

Please report suspicious walnut trees to the ODA at 855‐252‐6450 or by email at

Stay tuned for future developments including new training opportunities.




The Ohio State University

Joe Boggs

Assistant Professor

Commercial Horticulture Educator

OSU Extension, Hamilton County / OSU Department of Entomology

6412 Redmont Court, Liberty Township, OH 45044

Phone:  513-260-1474