Typhula incarnata

Typhula incarnata is a basidiomycete fungus in the family Typhulaceae that causes gray snow mold, also called speckled snow mold or Typhula blight, a winter disease of cool-season turfgrasses such as annual bluegrass, bentgrasses, fine-leaf fescues, Kentucky bluegrass, perennial ryegrass and tall fescue. It forms reddish-brown sclerotia roughly 1.5 to 3 millimeters across during cool, damp autumn weather; these germinate beneath snow cover and produce mycelium that infects grass tissue, protected from freezing by extracellular antifreeze proteins. As snow melts in spring, circular grayish-brown patches around 15 centimeters wide appear, though the grass typically recovers because the fungus does not kill the crown tissue.