Common Lawn Diseases
What to watch for in Minnesota lawns and how to treat each one.
Snow Mold
Gray or pink matted patches that appear as snow melts. Pink snow mold can kill the crown of the plant.
Treatment: Light raking to lift matted grass; for severe cases we dethatch with front-mounted tine rakes and baggers (no power raking). Avoid late-fall fertilization.
Dollar Spot
Small, silver-dollar-sized tan patches scattered through the lawn. Common in summer humidity.
Treatment: Improve drainage; water deeply and infrequently in the morning. Fungicide if severe.
Brown Patch
Circular brown patches several feet across, usually in mid-summer heat with high humidity.
Treatment: Reduce nitrogen, improve airflow, water in early morning only. Fungicide for outbreaks.
Red Thread
Pinkish-red threads visible in the leaf blades, typically in cool, wet spring or fall conditions.
Treatment: Usually a sign of low nitrogen - corrective fertilization typically resolves it.
Rust
Orange-yellow powder on shoes after walking through the lawn. Mostly cosmetic.
Treatment: Apply nitrogen, mow regularly to remove infected blades.
Necrotic Ring Spot
Circular dead patches with a green tuft in the center - common in Kentucky bluegrass.
Treatment: Aeration, reduced thatch, deep infrequent watering. Resistant cultivars in renovation.