The fungus is active in moist lawns at temperatures just above freezing. Circular patches (6-12 inches) will have a moldy appearance when fungus is actively growing - usually just as the snow melts. Under severe conditions, these smaller patches may grow together to form large, matted areas that appear to be dead. As the lawn begins to dry out the fungal growth slows. Patches can take on a light tan appearance, fading to light gray or white.
This disease rarely kills home bluegrass lawns, although young seedlings from a late fall seeding may be killed (fall sod will be OK).
Fungicide applications are not recommended when snow mold occurs in a home lawn. Spring fungicide applications will NOT effectively control or prevent the disease, nor will fungicide use hasten spring turf recovery.