Rapidly multiplying fungal disease arriving from Asian nursery stock, killing 3.5 billion American chestnuts by 1940. Formerly the tallest trees on the east coast, making up 50% of eastern hardwood forests.
aka Cryphonectria parasitica
American chestnut, European chestnut, Chinese chestnut (resistant), minor infection in some oak species
Threat to Trees
Rapid, usually causing mortality of everything above the canker within one growing season due to susceptibility to foreign disease
Wind, splashing rain, birds, and other animals carrying fungal spores to small cracks and wounds in the bark.
Signs & Symptoms
Small cankers at wounds and cracks which expand and girdle the stem, most common in seedlings
Older trees are more resistant to blight and can survive in spite of blight, but are not immune. Environmental stresses will break down this resistance, including climates and high elevations. Even in areas that have been completely cleared by fungal blight, the disease still remains in areas where all trees have been killed.
New York, ~1900
Maine to Georgia