Dollar spot is a fungal disease that affects most turfgrass species under low fertility. Leaves develop watersoaked, 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

Non-Chemical Management

Plant improved grass cultivars.
Provide proper culture including adequate, balanced fertilization.
Water in the mornings so grass can dry quickly. Deep, infrequent waterings reduce the possibility of drought stress.
Mow regularly at recommended height. Remove clippings.
Provide good drainage and aeration. Remove thatch and aerify as needed.
Prune trees and shrubs to increase light penetration and air circulation.
For more information on proper care of lawns see EB0482E, Home Lawns.

Select non-chemical management options as your first choice!

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.

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

ferti-lome F-Stop Lawn & Garden Fungicide
Active ingredient: myclobutanil | EPA reg no: 7401-505
ferti-lome Liquid Systemic Fungicide II R-T-Spray
Active ingredient: propiconazole | EPA reg no: 53883-184-7401
Scotts Lawn Fungus Control
Active ingredient: thiophanate methyl | EPA reg no: 538-88
Spectracide IMMUNOX Multi-Purpose Fungicide Spray Conc
Active ingredient: myclobutanil | EPA reg no: 9688-123-8845
This list may not include all products registered for this use.

Images

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Caption: Dollar spot Photo by: G. Stahnke
Caption: Dollar spot Photo by: G. Stahnke
Caption: Dollar spot: blade close-up Photo by: C.R. Foss

WSU Extension

Hortsense