Gray snow mold is a fungal disease that attacks turfgrass in areas where there are extended periods of snow cover. It is easier to manage if treated in a timely manner but can be fatal to turfgrass if left untreated.
Most turfgrass species are susceptible to gray snow mold if exposed to long periods of snow cover.
During winter and early spring, circular, light brown patches form in the lawn. A grayish-black fungus may be apparent along the border of the infected area. The disease may prevent new leaf growth in the spring. The causes of gray snow mold vary but can be attributed to improper drainage, snow accumulation on the unfrozen ground, or succulent turfgrass growth in late fall.
Gray snow mold can be relatively easy to manage. Simply raking the matted areas to remove dead grass can allow new leaf growth if done when the first symptoms are recognized. However, reseeding may be necessary if the damage is too severe. Fungicide treatments can also be effective if applied before a heavy snow cover but are not always necessary because turfgrass can easily recover from this disease. Consult your local landscape professional to see what treatments may be beneficial to your property.