How to Diagnose & Treat Maple Tree Infections & Insect Infestations

Check the leaves for signs of disease that appear as light brown, black tar and yellow spots with purple borders. All of these signs are associated with fungus infections. The trunk can become deformed and the leaves may fall off. Rake all leaves away from the trunk and dispose of to keep the fungus from growing. The fungus thrives on the leaves. Use fungicides for treatment and repellents made especially for fungus.

Look for yellow spots on leaves that eventually turn brown or a drab green before falling off. Caused by a bacterium, the condition is called "leaf scorch". It can cause branches to die and fall off. The disease appears after droughts in the late summer and early fall. The soil needs treatment that aids in water drainage. An arborist can treat the disease better than over-the-counter methods can.

Use a magnifying glass to check leaves for small insects such as aphids. Pick leaves that have spots, discoloration and holes. The aphids are only about 1/16th of an inch long and come in colors such as pink, black, gray, green and yellow. Another variety is a woolly alder aphid, which is white and fuzzy. Use an insecticide or introduce natural enemies such as ladybugs.

Search for mites on the leaves that appear in galls of various shapes and sizes. Usually appearing in early spring, the wart-shaped or felt-like patches keep the mites safe. The pests do not destroy trees. You can remove them by hand.

Look carefully for the Asian ambrosia beetle on Japanese maples. Infestation can destroy a tree. Check around early March for any signs of infestation. Treat multiple times with an insecticide.