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You are here: Home / Microbes / Species Profiles / Thousand Cankers Black Walnut Disease
Species Profiles

Thousand Cankers Black Walnut Disease

Thousand cankers - Invasive.orgScientific name: Geosmithia morbida (Kolařík et al. 2011)

Common name: Thousand cankers black walnut disease

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Selected Resources

Native To: Disease was first detected in the Western U.S.; the disease vector, the walnut twig beetle, is native to the southwestern U.S. and Mexico (Utley et al. 2013)

Date of U.S. Introduction: First observed in the 1990s, but not recognized until 2008 (Utley et al. 2013)

Means of Introduction: Unknown, but possibly through the transportation of logs and firewood (Randolph et al. 2013)

Impact: Fungal disease of walnut trees (Juglans spp.), particularly the black walnut (Juglans nigra), that is usually lethal within a few years; disease is transmitted by the walnut twig beetle, Pityophthorus juglandis (Tisserat et al. 2009)

Current U.S. Distribution: Widespread throughout the Western U.S.; first detected in the Eastern U.S. in Aug 2010



Selected Resources:

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Thousand Cankers Disease
Thousand Cankers Disease.

Gallery of Pests - Thousand Canker Disease
Nature Conservancy. Don't Move Firewood.

Phytosanitary Alert System - Geosmithia spp. and Pityophthorus juglandis
North American Plant Protection Organization.

National Pest Alert: Thousand Cankers Disease of Walnut
North Central Integrated Pest Management Center.

EPPO Global Database - Geosmithia morbida
European and Mediterranean Plant Protection Organization.

Invaders Factsheet: Thousand Cankers Disease
Ontario's Invading Species Awareness Program (Canada).

Federal Government

Plant Pests and Diseases Program: Plant Disease - Thousand Cankers Disease
USDA. Animal and Plant Health Inspection Service.

Special Projects - Thousand Cankers Disease
USDA. FS. National Forest Health Monitoring.

Pest Alert: Thousand Cankers Disease (Feb 2013)
USDA. FS. Northeastern Area State and Private Forestry.

State Government

Thousand Cankers Disease - 2010 Georgia Update (Sep 2010; PDF | 889 KB)
Georgia Forestry Commission.
See also: Forest Health Alerts & Updates on Emerging Threats to Georgia's Forests

Regulatory & Scientific Information: Thousand Cankers Disease
Indiana Department of Natural Resources. Entomology and Plant Pathology.

Plant Protection and Weed Control - Thousand Cankers Disease of Walnut
Kansas Department of Agriculture.

Invasive Tree Pests - Thousand Cankers Disease
Missouri Department of Conservation.
See also: For more information about Invasive Tree Pests (insects and diseases) that are not native to Missouri

Plant Diseases - Thousand Cankers Disease of Walnut
Minnesota Department of Agriculture.

Thousand Cankers Disease
Tennessee Department of Agriculture.

Forest Health - Thousand Cankers Disease
Wisconsin Department of Natural Resources.


Thousand Cankers Disease and the Walnut Twig Beetle in California
University of California. Statewide Integrated Pest Management Program.

Thousand Cankers Disease / Walnut Twig Beetle
Colorado State University. Department of Bioagricultural Sciences and Pest Management.

Emerging Threats: Thousand Cankers Disease of Walnut
Kansas State University. Kansas Forest Service.

Thousand Cankers Disease: A Threat to Black Walnut in Florida (Feb 2013)
University of Florida. Institute of Food and Agricultural Sciences.

Thousand Cankers Disease
Ohio State University. Extension.

Pacific Northwest Plant Disease Management Handbook - Thousand Cankers Disease (Black Walnut Decline)
Oregon State University. Extension Service.

Thousand Cankers Disease of Black Walnut: A New Pest May Threaten Texas Walnut Trees (Feb 2010; PDF | 1.46 MB)
Texas A&M University. Texas Forest Service.

Utah Pests Fact Sheet - Thousand Cankers Disease of Walnut (Aug 2011; PDF | 1.44 MB)
Utah State University. Cooperative Extension.
See also: Landscape Ornamental Insects for more fact sheets


Black Walnut Mortality in Colorado Caused by the Walnut Twig Beetle and Thousand Cankers Disease (Aug 2009)
Plant Management Network. Plant Health Progress.

Insects and Diseases - Thousand Cankers Disease
Walnut Council.


Kolařík, M., E. Freeland, C. Utley, and N. Tisserat. 2011. Geosmithia morbida sp. nov., a new phytopathogenic species living in symbiosis with the walnut twig beetle (Pityophthorus juglandis) on Juglans in USA. Mycologia 103(2):325-332.

Randolph, K.C., A.K. Rose, C.M. Oswalt, and M.J. Brown. 2013. Status of black walnut (Juglans nigra L.) in the eastern United States in light of the discovery of thousand cankers disease. Castanea 78(1):2-14.

Tisserat, N., W. Cranshaw, D. Leatherman, C. Utley, and K. Alexander. 2009. Black walnut mortality in Colorado caused by the walnut twig beetle and thousand cankers disease. Plant Health Progress.

Utley, C., T. Nguyen, T. Roubtsova, M. Coggeshall, T.M. Ford, L.J. Grauke, A.D. Graves, C.A. Leslie, J. McKenna, K. Woeste, M.A. Yaghmour, W. Cranshaw, S.J. Seybold, R.M. Bostock, and N. Tisserat. 2013. Susceptibility of walnut and hickory species to Geosmithia morbida. Plant Disease 97(5):601-607.

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Last Modified: Sep 03, 2018
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