Curtis Utley, CSUE, Bugwood.org
Black walnuts recently killed by TCD.
Karen Snover-Clift, Cornell University, Bugwood.org
Symptoms of flagging and dieback on a mature black walnut.
Karen Snover-Clift, Cornell University, Bugwood.org
Symptoms of advanced decline on a mature black walnut.
Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
Dieback starts at top and moves downward.
Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org
Symptom of TCD--thinning and dieback.
Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
Symptoms--dieback and yellowing.
Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org
Cankers on black walnut caused by TCD.
Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
Dieback in top of tree is characteristic of TCD.
Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
Numerous coalescing cankers beneath bark.
Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org
Cankers on black walnut (Juglans nigra).
Troy Kimoto, Canadian Food Inspection Agency, Bugwood.org
Canker and walnut twig beetle gallery on black walnut (Juglans nigra).
Ned Tisserat, Colorado State University, Bugwood.org
Branch cankers that have developed around walnut twig beetle galleries.
Ned Tisserat, Colorado State University, Bugwood.org
Large trunk cankers common in end stage of TCD.
Whitney Cranshaw, Colorado State University, Bugwood.org
Large trunk cankers common in end stage of TCD.
Whitney Cranshaw, Colorado State University, Bugwood.org
Chipped wood from black walnut killed by TCD. Many walnut twig beetle larvae and adults survived in the larger chips.
Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
TCD does not harm quality of the wood, so is at great risk of spread by movement of beetle-infested wood to new locations.