More information on the biology and management of powdery mildew on maples can be found in the PNW Disease Handbook maple powdery mildew webpage on this subject.
The other pictures are of powdery mildew on snowberry, Symphoricarpos, probaby S. albus.
Click on pictures to see larger images.
Powdery mildew on:
Photo: Rosetta, OSU
Symptoms and signs of powdery mildew on upper and lower leaves of 'Mazzard' cherry.
