Snow Mold

Winter weather conditions are very conducive to snow mold! When the snow disappears from your lawn, there may be areas of weak or dead turf. Often this damage is caused by a disease known as Snow Mold.

What Is Snow Mold? – There are two types of snow mold, Gray Snow Mold (Typhula spp) and Pink Snow Mold (Fusarium Nivale). Both types of snow mold develop under snow covers or prolonged periods of cool, wet weather. The optimum temperatures are in the 32 to 45 degree F range for both, however, the pink snow mold can cause significant damage at temperatures of 65 degrees. Both snow molds develop most rapidly when snow has fallen on unfrozen ground.

How To Identify Gray Snow Mold – Where snow mold has been active, the turf commonly develops rough circular spots of matted, silver-gray turf. Often these spots are so numerous that an entire area may be disfigured. The trouble is most likely to be seen on the shaded side of a building, in the shade of trees and shrubs, or similar areas where moisture remains for a long time in late winter.

How To Identify Pink Snow Mold – As pink snow mold develops, the initial infections are irregular patches of pale yellow grass, ranging from two inches to over one foot in diameter. As the disease develops further, the individual blades will take on a bleached appearance and the patches become whitish-gray. For this reason, pink snow mold is often confused with gray snow mold.

Both snow molds develop mycelium (which resemble cob-webs) that form a white mat under prolonged moist conditions. However, there is normally more mycelium with gray snow mold.

How To Control – Once snow mold damage has occurred, the only possible procedure is to loosen the discolored, matted grass with a leaf rake (without digging into the soil), fertilize the entire lawn and see what will develop once good growing weather is at hand. Often the snow mold fungus kills only the tops of the plants and they recover with a few weeks of good growing weather. In more serious instances entire areas of turf, roots and all, will be destroyed and the spots will not recover. After a few weeks of good growing weather, it is reasonable to assume that any turf that has not recovered, will not do so. Then it is the time to do any necessary patching by loosening the soil and planting more seed. The delay to see what may develop is usually well worthwhile. Often the most devastating attacks of snow mold will recover without any reseeding.

If you need more help or information with this topic or any other lawn or tree care questions, please contact us.

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