Lawn Mold Killer

Disease Identification

• Lawns often display pink and gray mold, sometimes referred to as snow mold, during the early spring immediately following the melting of snow. Gray mold is caused by the Typhula fungi, and pink mold is the result of Microdochium nivalis. Home lawns are also susceptible to slime mold, caused by Physarum fuligo and Mucilago crustacea fungi.

Symptoms

• Snow mold starts with the appearance of tan patches in cold and wet lawns. The grass is matted with gray or pink fungal growth at the margins. Spherical-shaped fruiting bodies called sclerotia are evident within the infected areas. Slime mold appears in the form of 4- to 8-inch-diameter gray to black patches on the lawn's surface. The fungal patches have an oily and slimy look, and dry into a crust in bright sun. Dark brown to black fruiting spores are visible within the infected areas.

Recommended Fungicides

• Since the damage caused by snow mold is not severe in nature, fungicidal control options are generally not recommended. The affected grass is only a little slower to get green in the spring. In cases where the symptoms are severe and tend to occur repeatedly, use products containing thiophanate-methyl. There are no mold killers for controlling slime mold. As cited by the Alabama Cooperative Extension, chemical controls are not only unnecessary but also ineffective.

Use Suggestions

• Apply fungicides to grass during October and November to help minimize symptoms of snow mold in the coming spring. Do not use nitrogen fertilizers excessively in the fall, as this makes grasses more prone to the disorder. Cultural management practices are sufficient enough to bring slime mold symptoms under control. The mold dries rapidly in the sun and is easily removed by raking or sweeping the grass. Use a powerful stream of water to wash away dried spores from the lawn.