Lawn and Turf: Dollar spot

categories: Lawn and Turf Lawn and Turf Diseases

revision date: 2024-07-22 12:34

Biology

Dollar spot is a fungal disease that affects most turfgrass species under low fertility. Leaves develop water soaked, dark lesions which become light tan with a reddish-brown margin as they dry. Lesions are often hourglass-shaped and may involve the whole leaf blade. Leaf blades may be girdled, and crowns and roots may be decayed when the disease is severe. The affected areas appear as small (3″ or less), circular, somewhat sunken patches in the lawn. The patches are yellow brown to gray in color, often with reddish-brown margins. The fungus may be present as a cobweb-like mass of whitish mycelia at the edge of the patches. The fungus survives in the soil or in infected plant tissues and debris. Warm, humid weather and cool nights favor disease development, which is more severe on drought-stressed grasses. The fungus can be spread by infected clippings. This is not a major disease in western Washington.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Provide proper culture, including deep, infrequent waterings and adequate fertilization.
• Rake and loosen soil in affected areas. Aerate soil and water the area deeply. A grass-type wetting agent can be used to help rewet the soil.
• After rewetting, reseed affected areas and fertilize and water properly.
• Remove the sod, mix soil in affected areas in the upper 6 to 8 inches of soil with a rototiller, and reseed or put new sod in the area.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Follow label directions when this disease has been diagnosed.
• Do not repeatedly apply the same fungicide or fungicides with the same active ingredient as tolerant strains may result.
• Carefully check product labels.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• ferti-lome F-Stop Lawn and Garden Fungicide
  Active ingredient: myclobutanil [EPA registration number: 7401-505]
• ferti-lome Liquid Systemic Fungicide II R-T-Spray
  Active ingredient: propiconazole [EPA registration number: 53883-184-7401]
• Spectracide IMMUNOX Multi-Purpose Fungicide Spray Concentrate
  Active ingredient: myclobutanil [EPA registration number: 9688-123-8845]
• This list may not include all products registered for this use.