Thousand Cankers Disease hitting Northern Colorado black walnut trees


The decline of black walnut trees in Colorado was initially noted in 2001, and it was suspected to have been drought-related. Thanks to leading research by Colorado State University professors Ned Tisserat and Whitney Cranshaw in the Department of Bioagricultural Sciences and Pest Management, in 2009, the cause was determined to be a fungus (Geosmithia morbida) introduced into the branches and stems of black walnut trees by the walnut twig beetle.