Photo by Ali Harivandi

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Hosts

All turfgrass species

Symptoms

Fairy ring symptoms vary depending on the species of fungus. A dark green band of turf may develop in a circle or semi-circle, or a ring of brown, dying grass may occur. Mushrooms may or may not be present. White, fungal mycelia may be observed under the thatch layer.

Conditions favoring disease

Soils with a thick thatch layer or undecomposed organic matter favor disease development. Lawns with low fertility or insufficient water tend to have more damage than lawns with adequate fertilizer and water.

Prevention and management

Apply adequate nitrogen to mask symptoms and increase activity of beneficial soil organisms. To improve water penetration, aerate and water heavily in holes for several days. Dethatch the lawn if the thatch layer is more than 1/2 inch (1.2 cm) thick. Rake mushrooms to improve the appearance of the turf. Dig out the turf and root zone that contains a white, cottony mass to a depth of 12 inches (30 cm) and 2 ft (60 cm) beyond the outer edge of the ring. Refill the area with clean soil and reseed or re-sod. Fungicides are available but they have not been observed to reliably control fairy ring.

For more information on mushrooms in lawns, refer to:
Pest Notes: Mushrooms and Other Nuisance Fungi in Lawns