Maple tree types number in the hundreds with thousands of cultivars. Maple trees are found throughout the Northern Hemisphere and are mainly deciduous. There are a few species found in subtropical Asia. Maples are known for their attractive fall foliage, however, the tree is susceptible to leaf diseases such as phyllosticta leaf spot, leaf hoppers and anthracnose.
Phyllosticta Leaf Spot
Phyllosticta leaf spot is caused by a fungus that attacks the leaves of maple trees, including Japanese, red, silver and sugar maples. The symptoms range from irregular-shaped spots or lesions to massive leaf dieback, according to the University of Nevada Extension. The fungus attacks in wet weather during the spring and summer. Treatments include spraying the tree with fungicide and removing affected branches.
Leaf hoppers are insects that feed on the leaves of the maple tree. The insects are so-named because of their ability to move backward, forward and sideways. There are several different species of leaf hopper, according to the Missouri Botanical Garden. The damage these different species cause ranges from white spots on leaves to drying and curling of leaf edges to black spots on the underside of leaves. Treatment includes using insecticides or insecticidal soap, using traps or allowing the bug's natural predators to control the leaf hopper population.
Anthracnose is caused by a fungus that attacks new shoots and leaf tissue. Symptoms include dark spots and scorching of leaves, according to the University of Minnesota. The tree may also experience leaf dieback during the summer. The fungus attacks during cool, wet weather and will grow dormant as the weather gets drier. In most cases, anthracnose will clear on its own and is considered a cosmetic disease that does no lasting damage to the tree. In severe or persistent cases, fungicide can be used. Preventive measures include avoiding over watering and removing affected branches.