Leaf Spot/Melting Out
Lesions develop on the leaf blades
Photo courtesy of Kansas State University
Helminthosporium and Drechlera spp. are the primary pathogens for this disease. All cool-season grasses can be affected. Common types that are affected are, Kentucky bluegrass is most susceptible, as well as Bermuda grass. Disease normally occurs late winter through fall depending on the disease causing species.
Signs and Symptoms:
Tiny, circular, dark spots occur initially. These spots enlarge and turn purplish in color. Later, the centers of the spots become light brown. Lesions on the leaf sheaths cause girdling and the collapse of plant tissues. This crown rot causes turf to thin or “melt out”.
Favorable Conditions:
Cool or warm wet weather favors disease occurrence depending on the causal species. Overcast skies and improper mowing also contributes to disease occurrence.
Cultural Prevention and Control:
Proper cutting height and frequency for the turf species being grown is important. Regular irrigation to encourage turf growth is also necessary.