Snow mold diseases can cause problems on turf during fall, winter and spring. Two types of snow mold occur in the northern U.S., Gray Snow Mold and Pink Snow Mold.
Both pathogens remain dormant between active seasons in soil or in debris of previously diseased leaves. Under ideal conditions spores develop and are spread by wind or splashing rain.
Symptoms begin as small spots 1-3 inches in diameter. Pink Snow Mold can expand to 12 inches and have a pink margin. Gray Snow Mold can expand to 2 feet with a gray-white halo.
Tall or improperly mown turf grass is more prone to snow mold. The tall, matted grass blades produce an ideal climate for snow mold development.
Raking the damaged turf in the spring will assist in recovery. Raking removes matted grass, improves air circulation and stimulates new grass growth…but don’t rake too aggressively because that can potentially kill the grass.