Melting out is especially common in bluegrass. Small, round, gray, brown, or purplish black spots on the leaf blades spread to kill the leaves and roots. The disease is most prevalent during high temperatures and humidity, and on closely cropped lawns. Large areas seem to die almost overnight. Don't cut your grass too short, and avoid excessive amounts of spring nitrogen. Reduce the shade in your yard, and iimprove aeration and drainage. Use fungicides when the disease first appears.
