Grapevine trunk diseases can cause a decline in vine vigor and health over time. The best way to determine if your vineyard has trunk disease is to cut into the vine and look for cankers. This video shows you how to look for the cankers during the dormant season while pruning.

• Cut into dormant cordons, starting from distal portions of the cordon and work toward the head of the vine (top of the trunk). Make incremental cuts as you go, inspecting the wood for signs of trunk disease.
• Signs of the disease include dark brown/black colored wood. Healthy tissue will be creamy tan in color.

• To determine which grapevine trunk disease has infected the vines, send a whole vine sample or all of the sections that you cut, to a disease diagnostic lab to confirm the type of trunk disease infecting the vine.
• The Oregon State University Plant Clinic can run diagnostics for Oregon and elsewhere. However, check with your state’s land grant university to see if they have a plant diagnostic lab.