WSU Extension

Hortsense

Lawn and Turf : Yellow patch
(revision date: 6/22/2015)


Biology
Yellow patch is a fungal disease which may affect bluegrasses, annual bluegrass, and bentgrasses. Symptoms are typically seen in fall, winter, and spring. Light brown to yellow patches and rings form on affected turfgrass. Lesions on the leaves are rarely seen. The patches may recur in the same locations whenever conditions are favorable. Cool, moist conditions favor disease development. Prolonged leaf wetness, excessive thatch, poor drainage, cloudy weather, and excessive fertilization also contribute to disease development.
Management Options

Non-Chemical Management
  • Provide proper culture, including adequate, balanced fertilization and deep, infrequent watering.
  • Water in the morning so grass can dry quickly. Do not overwater.
  • Provide good drainage.
  • Avoid practices which favor disease such as excessive fall applications of nitrogen.
  • Mow regularly at the recommended height.
  • Remove thatch and aerify as necessary.
  • For more information on proper care of lawns, including mowing heights and fertilizer recommendations, see EB0482E, Home Lawns.
Select non-chemical management options as your first choice!

Chemical Management

None recommended. Fungicides effective in controlling this disease are available to home gardeners, but are typically packaged in quantities appropriate only for commercial applicators.

Images
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Caption: Yellow patch fungal mycelium
Photo by: R.S. Byther
Caption: Rhizoctonia hyphae under microscope
Photo by: G.A. Chastagner