Leaf Diseases in Japanese Red Maples

Japanese red maple, or Acer palmatum Atropurpureum, is a small maple tree known for its vibrant red foliage. Although relatively hardy growing, the Japanese red maple is susceptible to some leaf diseases.

Leaf Scorch

• Leaf scorch is a disease that occurs when the Japanese red maple is exposed to improper growing conditions and too much sunlight. Symptoms consist of yellowing between leaf veins and margins and death of infected areas, according to the University of Missouri Extension. Although leaf scorch cannot kill a tree, it can weaken it, thus making is susceptible to other diseases and harmful insects.

Phyllocticta Leaf Spot

• Caused by the fungus Phyllocticta minima, Phyllocticta leaf spot is a leaf disease of the Japanese red maple. Symptoms consist of circular, tan spots with purple to red borders, according to the Ohio State University Extension. The disease is mainly aesthetic and poses little harm to the tree.

Control

• Once leaf scorch occurs, it is impossible to cure, but avoiding over-fertilization and using screens to prevent too much sunlight from damaging the tree prevents further damage, according to the University of Missouri Extension. Fungicidal control is an effective method of control for severe infections of Phyllocticta leaf spot, according to the Ohio State University Extension.