Question
Hi - we are in Oak Park, IL right outside of Chicago; our beautiful King Crimson maple tree has had white powdery-looking spots on the leaves most of the summer and continuing now. I have seen the same spots on other King Crimson trees in the area. The leaves and tree otherwise looks very healthy.  What are the white spots, and are they a cause for concern?  If so, what can be done to eliminate them?  thanks

Answer
These are a leaf spot fungus and are not a real concern to the overall health of the tree. When the leaves fall rake them up and move them off the site. This will cut down on the amount of fungi spores that may infect next spring. IF you see the spots early in the spring you can spray the new leaves with a fungicide to protect them.