Overview
Powdery Mildew Is A White Fungus
Powdery mildew is fungal turf disease that is easy to spot and diagnose because of the flour-dusted appearance it gives to your lawn.
This particular lawn disease is largely cosmetic and doesn't usually cause damage to the affected grass, although it can become distracting and unsightly in your yard.
Appearance
Powdery mildew causes areas on your turf to appear to have flour sprinkled over the grass blades, which gives the affected areas a white or grayish cast. Very small spores are covering the grass blades, which appear as a powdery substance covering each individual leaf blade. Eventually, the entire grass blade can be covered in the white spores.
The areas of affected grass start out in small patches, but can spread to affect larger areas, since the spores spread on the wind. It will generally only take hold in the areas that provide the best conditions to powdery mildew development: damp conditions in shady areas.