Powdery mildew can be identified as grayish white powdery patches covering the surface of leaves and stems. There are many different strains of powdery mildew, but the basic treatment is the same for most varieties. Powdery Mildew is one of the most common diseases and infects all types of plants and trees, outdoors and indoors.
Powdery Mildew grows on the outside of leaves and unlike many other bacterial or fungal infections, does not require damp surfaces, as it can grow on both dry and wet leaves. Infections are from the wind blowing fungal spreads from plant to plant.
As the powdery mildew spreads, the leaves eventually turn yellow and wither and the disease can kill entire branches.