Break the (snow) mold

Persistent problem Snow mold can show up in cool-season turf without heavy snow cover. (Photo: Grasshopper Lawns)

Snow mold is a persistent problem on cool-season turf each year, regardless of how much it snows, according to John Patterson, general manager of Grasshopper Lawns, in Larksville, Pa.

Pink snow mold appears in small tan or pinkish circular patches up to 6 inches in diameter, and gray snow mold patches can be several inches to several feet in diameter.

Two lawn care operators (LCOs) offer insights to help beat back snow mold before it appears or after telltale patches appear on a lawn.

Cultural practices

Patterson recommends a good yard cleanup at the end of fall and dropping mower blades down a level. Shorter turf minimizes moisture getting trapped and increases air circulation.

Marv Kottke, owner at Spring Touch Lawn & Pest Control in St. Paul, Minn., says aeration is key in the fall for breaking up thatch and helping air out turf. Kottke suggests adjusting irrigation systems, as overwatering can cause snow mold. If problems continue in a shady area, trim or remove trees to allow more sun.

Chemical control

Patterson says the worst snow mold damage happens in March when snow covers turf and goes through melt and freeze cycles. “Once you get to March, if you’ve got snow mold and it’s far gone, we’ll rake it out or have the customer rake it out and fluff the turf up,” he says.

To prevent snow mold in March, Grasshopper Lawns relies on fungicides early. “We do a fungicide application as a preventive and, if able, put another treatment on if there’s a January thaw,” he says. The company typically uses pentachloronitrobenzene or triadimefon-trifloxystrobin. Kottke currently uses azoxystrobin-propiconazole for both preventive and curative snow mold control.