Butternut Canker Signs and Symptoms

Some of the common signs and symptoms of the butternut canker include:

• dying branches in the upper, sunlit crown (shaded branches die off normally)
• sunken, elongated, diamond-shaped cankers, dark brown to black in colour, found on the branches or the stem
• older cankers may show successive rings of callus loosely covered with shredded bark
• in spring, a thin black fluid oozes from cracks in the bark
• in summer, fall and winter, the black fluid leaves a dried sooty stain on the outside of the bark at the canker site
• underneath the bark, the wood is stained dark brown to black in a diamond shape
• epicormic branching below dead or infected areas on stem or branches

Canker on trunk	Epicormic branching
Crown dieback due to canker infection
Recent canker on trunk	Mature butternut canker