Brown Patch in Maryland Lawns

Along with the start of summer time comes a common lawn disease for Maryland homeowners’ lawns called brown patch. The disease is caused by several fungal species of Rhizoctonia.  Rainy summers are worse, but even drier summers have brown patch disease pressure from moisture that develops from evening dew. Although tall fescue is the recommended turf variety for Maryland lawns, most cultivars are still very susceptible to this problem disease.

About Brown Patch

• Prevalent June-September, when daytime temperatures are 85º or above, nighttime temperatures are above 68º, and relative humidity is high.
• Symptoms – Circular yellow-brown patches of thinned turf. On individual blades, elongated lesions bordered above and below by tan or chocolate-brown bands.
• Brown patch affects all turfgrass, especially tall fescue and perennial rye.

Reduce Brown Patch Severity

• This disease does not kill the crown of the turf. Most tall fescue lawns will recover with proper fall fertilization and the return of rainfall.
• During severe summers overseeding in September will help to thicken up thin areas. Choosing tall fescue cultivars with more resistance to brown patch will also help reduce the overall disease severity next year. See our fact sheet on recommended turfgrass cultivars for Maryland.

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By Dave Clement, Principal Agent, University of Maryland Extension, Home & Garden Information Center