- Young cankers appear as round flattened, bark covered areas on main trunk or larger branch
- As cankers age, the flattened surface turns black and bark begins to fall off revealing decaying wood in a target shape pattern below
- Branch stub or other wound is often visible at center of the canker
- White to buff-colored fungal growth may be seen around outer portions of expanding canker if bark is removed
- Old cankers may develop a thick ring of wound wood surrounding the canker, making that area wider than the trunk above or below
- Occurs on all maples but common on sugar maples in forest settings and Norway maples in urban settings
- More information on Eutypella canker...