Pink snow mold (Microdochium nivale) develops during periods of snow cover, with symptoms of the disease becoming evident as the snow melts. The disease appears in roughly circular patches from 2" - 1' in diameter that are white or light tan in color. A ring of salmon or pink-colored growth is present on the outer edge of patches when the disease is actively developing. The infected leaves within the patches are usually collapsed and matted down upon themselves.
Pink Snow Mold may also infect turfgrasses even without snow cover during periods of cool, wet weather. The disease is then referred to as Microdochium patch. The symptoms of Microdochium patch are slightly different than pink snow mold. The patches are similar to pink snow mold in size and shape, but are reddish-brown or salmon-colored and greasy in appearance. When the disease is actively developing, the patches may be surrounded by a dark brown or bronze ring.
Disease activity is most severe when snow falls on unfrozen ground; however, activity can occur without snow cover during cool (less than 60°F) wet weather. Excessive foliar growth and thatch buildup are the most important factors encouraging development of pink snow mold and Microdochium patch. Restricted air movement, poor soil drainage, inadequate levels of potassium, and heavy traffic can also enhance the disease. The disease may also develop under tree leaves that remain on the turf for long periods during cold, wet weather.