Gray Snow Mold and Pink Snow Mold Are Not the Same Patch

"Snow mold" sounds like one thing. It's really two different problems, and knowing which one you have tells you how worried to be.

Gray snow mold

• Looks like: circular patches of straw-colored to grayish-brown grass, matted down, often with a gray web on top as the snow melts.
• The tell: tiny dark specks on the dead blades. These are the fungus's resting bodies (sclerotia). Some are reddish-brown, about the size of a pinhead. Others look like flecks of black pepper.
• Needs: long snow cover, usually 40 to 60 days or more. That's why it's worst in the snowbelt and under big snow piles.
• Damage: usually just the leaf blades. The crowns survive, and the grass grows back in spring.

Pink snow mold

• Looks like: circular patches that are pinkish-orange to tan at the edges, sometimes with a white-to-pink fuzz when wet.
• The tell: no specks. The pink edge in sunlight.
• Needs: cold and wet. Temperatures roughly 35 to 60°F with lots of moisture. It doesn't need snow. It can show up in a rainy November, a soggy March, or during a winter with no lasting snow cover.
• Damage: can be worse than gray. It can kill the crown, not just the blades, especially on bentgrass and young grass.

Why it matters

If you live where snow sits for months, gray snow mold is the one you'll see most. If your winters go back and forth between freezing and thawing, with rain and slush, pink snow mold is more likely, and it can be active even in years you'd think were too mild for "snow" mold.

What to do

For both, prevention is the same: get leaves off, mow the last time a bit shorter, go easy on late-fall nitrogen, and avoid big snow piles on the lawn. See wet leaves under the first snow.

In spring, rake the matted patches gently so they dry out. If a spot is still dead after the lawn greens up, reseed it. See snow mold prevention and recovery.

Preventive fungicide is standard on golf greens. On a home lawn, it's rarely needed.

Sources (3)

University of Wisconsin Extension: Typhula blight · Penn State: Gray and speckled snow mold · UW–Madison Koch Lab: Snow molds

Photo: Gray and pink snow mold by Rutgers University, courtesy.

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