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How to Manage Pests

UC Pest Management Guidelines

Fairy ring brown field mushrooms, Agaricus cupreobrunneus, fruiting in two circles in a field.


Fairy Ring

Pathogens: Agrocybe pediades, Marasmius oreades, Lepiota spp., etc.

(Reviewed 9/09, updated 9/09)

In this Guideline:


Fairy ring is caused by a number of species of mushroom-forming fungi including many basidiomycetes in the order Agaricales. For example, Lepiota spp. are common in southern California, Marasmius oreades has been found in central and northern California, and Agrocybe pediades occurs in both southern and northern California. Many of these fungi are poisonous and must not be eaten.

Fairy rings are circular or semi-circular and can range in size from a few centimeters up to many meters in diameter. Symptoms can be variable, depending on the species of fungi, and include: 1) dark green rings with no dead turf; 2) dark green rings with a thin ring of dying or dead turf inside or outside the green ring; 3) rings of dying and dead turf with a hardened hydrophobic layer of soil that is difficult to irrigate; and 4) rings of mushrooms without a visible effect on the turf. Weeds commonly invade infested areas.

There are two types of fairy rings, edaphic (non-superficial) or lectophilic (superficial). Edaphic rings are generally formed by fungi that inhabit the soil underneath the turf. These frequently cause a hardened hydrophobic layer of soil above the areas of their active growth that prevents water penetration into the soil and often causes plant death. Rings of dead turf are frequently associated with this type.

Lectophillic rings are caused by fungi that inhabit the thatch layer and decomposed plant debris, litter, and old thatch. These rings are characterized by a slight depression of the affected areas surrounded by dark green rings of turfgrass where the fungi are breaking down plant material and releasing nitrogen. A hard hydrophobic soil layer is not associated with this type of fairy ring.

The fungus survives as a white mass of mycelia in the soil or thatch layer, or can be spread by spores dispersed by the mushrooms produced by the rings. In some cases, rings or mushrooms can appear in the turfgrass and cause no apparent damage.


All grasses are susceptible to fairy ring.


A dense thatch layer contributes to the availability of undecomposed matter, as does the addition of composts or other organic material that have not been fully decomposed. Also, turfgrass growing in low fertility soils with insufficient irrigation appears to suffer more damage from fairy rings than turfgrass with adequate fertility and irrigation.


A turfgrass management program that provides proper fertilization and irrigation along with regular dethatching of the turfgrass will help prevent the development of this disease. Fungicide treatment or soil removal may be necessary if fairy ring becomes a problem.

Cultural Control
To avoid or reduce symptoms, apply adequate nitrogen and water. Symptoms of superficial rings can be masked by nitrogen applications. If fairy rings are present, aeration followed by heavy watering for several weeks may help reduce symptoms; soil wetting agents may improve water penetration. Proper thatch management and regular dethatching can contribute to a reduction in the disease. Fairy ring can be eliminated by removing the turf and root zone with the soil containing the white, cottony, mycelial mass. If fairy ring symptoms consist only of mushrooms and there is no zone of dark green grass, the mushrooms can be raked off and disposed of. While this will not weaken or control the fungus, it will improve the turf's appearance.

Treatment Decisions
Fungicide applications of azoxystrobin appear to provide good control of the disease when used properly. Flutolanil applications provide some suppression; control may be improved if applications are used in conjunction with cultural practices.

Common name Example trade names Ag Use
NonAg Use
(trade name)   (hours) (hours)

Calculate impact of pesticide on air quality
Bee precaution pesticide ratings
When choosing a fungicide, consider general properties as well as information relating to environmental impact.
  MODE OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) 4 until dry
  MODE OF ACTION GROUP NAME (NUMBER1): Carboxamide (7) 12 until dry
* Permit required from county agricultural commissioner for purchase or use.
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information, see http://www.frac.info/). Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode of action Group numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different mode of action Group number; for fungicides with other Group numbers, make no more than two consecutive applications before rotating to fungicide with a different mode of action Group number.
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Agricultural use applies to sod farms and commercial seed production.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Turfgrass
UC ANR Publication 3365-T
F. Wong, Plant Pathology, UC Riverside
M. A. Harivandi, UC Cooperative Extension, Alameda County
Acknowledgment for contributions to Diseases:
J. Hartin, UC Cooperative Extension, San Bernardino County
M. E. Grebus, Plant Pathology, UC Riverside

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