The red maple grows wild all over eastern North America. This beautiful tree is known for its iconic red foliage and delicious maple syrup. The red maple tree can reach over 90 feet tall and live for over 100 years. But although the maple may look majestic, it is not impervious to disease.
Red maples are highly susceptible to anthracnose. The fungus that causes the disease often strikes after a period of cool, wet weather during bud break. An infected maple tree will have leaves that turn purplish brown in large irregular spots around their veins. To control the spread of anthracnose, prune all discolored leaves and remove leaf litter immediately. To prevent subsequent outbreak, spray the tree with a fungicide prescribed for anthracnose in early spring during bud break.
Maple wilt is a common and often deadly fungal disease. Once infected (usually in summer), a red maple's limbs will die back and the leaves will drop. And some trees exhibit olive green streaks in their sapwood. Infected trees may die in one season while others deteriorate slowly over several years. Once maple wilt sets in, it is difficult to get rid of. If caught early enough, pruning the affected foliage may save the tree. However, if the disease continues to spread, the tree must be uprooted and destroyed.
Sapstreak disease is a fatal fungal disease. The first symptom of sapstreak is stunted foliage all over or on a portion of the crown. As the disease progresses, the crown dies section by section until the tree is dead in three to four years. There is no cure for sapstreak disease. Infected trees should be uprooted and destroyed.
Maple Leaf Gall
There are two types of gall that affect red maple trees. Maple velvet maple gall is passed to the red maple by a mite. Maple velvet leaf galls are circular or oval hair-like mats that can be bright red or green. Maple bladder gall is also spread by a mite and causes pimple like bumps on the leaves that are initially green but then turn red and finally black. Both types of gall are unsightly, but neither cause more than cosmetic damage. Rid the tree of gall by eliminating the mites that cause it with a pesticide prescribed for tree mites.