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Thousand Cankers Disease is Widespread in Black Walnut in the Western United States

    Authors and Affiliations
    • Ned Tisserat
    • Whitney Cranshaw , Professors, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, CO 80523-1177
    • Melodie L. Putnam , Director, Plant Disease Diagnostic Lab, Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
    • Jay Pscheidt , Professor, Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
    • Charles A. Leslie , Director, Walnut Improvement Program, Department of Plant Sciences, University of California, Davis, CA 95616
    • Marion Murray , IPM Extension Associate, Department of Biology, Utah State University, Logan, UT 84322
    • James Hoffman , Plant Pathologist, USDA Forest Service, Boise, ID 83709-1663
    • Yvonne Barkley , Associate Extension Specialist, Idaho Extension Forestry, University of Idaho, Moscow, ID 83844-1140
    • Kathleen Alexander , City Forester, City of Boulder Forestry, 5200 Pearl Street, Boulder, CO 80301-2437
    • Steven J. Seybold , Research Entomologist, USDA Forest Service, Pacific Southwest Research Station, Davis, CA 95616

      Thousand cankers disease of black walnut is caused by aggressive feeding by the walnut twig beetle and subsequent canker development around beetle galleries caused the fungus Geosmithia morbida. The authors We confirmed the presence of G. morbida from symptomatic black walnut or hybrids in California, Colorado, Idaho, New Mexico, Oregon, Utah, and Washington. Thousand cankers disease continues to cause extensive mortality to black walnut over a wide geographic region and is intensifying in the western United States.

      Accepted for publication 2 June 2011. Published 30 June 2011.