Question
Purchased just a few years ago, the leaves of my golden maple are slowly turning brown. These brown spots are slowly spreading from leaf to leaf and causing leaves to loose their colors and falling prematurely. I live in Sterling Hts., MI the maple is well cared for. Can you Help?
Thank you
Jim

Answer
Sounds like leaf spots. There are two common ones.

Phyllosticta Leaf Spot: This disease, also known as purple eye, is caused by the fungus Phyllosticta minima. On the leaves, spots appear with pale yellow centers and purple borders. The spots are irregularly round and ?inch in diameter. Black fruiting bodies of the fungus develop in a circle in the centers of the spots. These fruiting bodies occur in greater numbers on the upper leaf surface. Severe infection can result in partial defoliation of the tree. Often the disease goes unnoticed until leaf accumulation occurs under the tree.

Prevention and Treatment: The fungus survives the winter in fallen leaves. In the spring spores are produced and dispersed to the new leaves of susceptible trees. Rake up all fallen leaves. Fertilization and watering may help to reduce the disease. 慉utumn Flame? 慣ilford?and 慓erling?red maple varieties are relatively resistant to leaf spot. For chemical control use a fungicides.

Spraying three times at two-week intervals with a copper fungicide (Hi-Yield Copper Fungicide, Ferti-lome Black Spot & Powdery Mildew Control) or mancozeb (Bonide Mancozeb Flowable, Southern Ag Dithane M-45, or Dragon Mancozeb Disease Control) starting when the leaves begin to unfurl in spring will provide control. Read and follow all directions on the label.

Tar Spot: Tar spot is caused by the fungus Rhytisma acerinum. Spots arise in late spring or early summer after leaves attain full size. At first the infected tissue is light green or yellow. Then, during late summer, raised, shining black, tarlike dots develop within the yellow spots on the upper leaf surfaces. The lower surface of a leaf beneath a large tar spot turns brown, but the surface beneath speckled tar spots remains yellow. Leaves with multiple spots may wither and drop prematurely, but seldom so early or in such quantities as to threaten the health of the tree.

This disease is more common in the forest, but may be seen in some landscape situations. Tar spots are among the most showy and least damaging foliar diseases.

Prevention and Treatment: The fungus survives the winter in fallen leaves. Rake up and discard the leaves in fall. For chemical control use the same fungicides recommended
for control of Phyllosticta Leaf Spot.