Thousand Cankers of Black Walnut
Cankers caused by the fungal pathogen Geosmithia sp. nov. form wherever the walnut twig beetle (Pityophthorus juglandis) probes the wood. Eventually hundreds or thousands of cankers form, coalesce and cause tree mortality. Photo by Dr. Ned Tisserat, Colorado State University.
Thousand Cankers Disease (TCD) is a pest complex that is causing mortality in walnut in many western states. It is caused by the walnut twig beetle (Pityophthorus juglandis) and an associated fungus (Geosmithia sp. nov.). Black walnut (Juglans nigra) is highly susceptible to this disease, but TCD has not yet been found in the native range of black walnut. The following pest alert from Colorado State University provides an overview of TCD.
If you suspect you have seen TCD in Missouri, please contact the Missouri Department of Agriculture, Office of the State Entomologist at (573) 751-5505.
For those outside of Missouri, the contact information for your state plant regulatory official can be found at the National Plant Board Web site at www.nationalplantboard.org under “membership”.
Thousand Cankers Disease of Black Walnut National Conference
The first Thousand Cankers Disease of Black Walnut National Conference was held in St. Louis, Missouri on November 3-4. Hosted by the Missouri Department of Agriculture and the Missouri Department of Conservation, it was attended by over 145 participants from 24 states and Washington, D.C. Those in attendance traveled to St. Louis to learn more about Thousand Cankers Disease (TCD), and to discuss a national response to protect black walnut (Juglans nigra) in its native range. As a result of the conference, a national taskforce is being developed, and several state and federal agencies are working together on a unified response for survey, outreach, regulatory and research efforts. The program booklet with list of sponsors and speaker bios is available here.
The following are materials from the conference.
Conference Speakers
Ned Tisserat, Colorado State University: slideshow, notes
Whitney Cranshaw, Colorado State University: slideshow, notes
Kathleen Alexander, City of Boulder, Colorado: slideshow, notes
Steve Seybold, US Forest Service: slideshow, notes
Larry Frye, National Walnut Council: slideshow, notes
Mark Coggeshall, University of Missouri: slideshow, notes
Bruce Moltzan, US Forest Service: slideshow, notes
Scott Pfister, USDA-APHIS-PPQ: slideshow, notes
Collin Wamsley, Missouri Department of Agriculture: slideshow, notes
Jerry Van Sambeek, US Forest Service: slideshow, notes
Brian Hammons, Hammons Products: slideshow, notes
Jay Pscheidt, Oregon State University: slideshow, notes
Harlan Palm, Missouri Walnut Council: slideshow, notes
Chris Ranger: slideshow, notes
Jason Oliver: slideshow, notes
Panel Discussion (moderated by Manfred Mielke, US Forest Service): slideshow, notes
Links of Interest
National Plant Board: contact information for state plant regulatory officials
National Association of State Foresters: contacts for the state forester in each state
National Plant Diagnostic Network: NPDN diagnostic lab for each state
Walnut Council: also has links to state associations
Other TCD-Related Documents
TCD Pathway Analysis conducted by USDA-APHIS-PPQ
TCD Q&A from Colorado State University
TCD Field Identification Guide from Steve Seybold, US Forest Service
TCD Economic Assessment for Missouri from the Missouri Department of Conservation
