Mushrooms may appear periodically in the vigorous outer zone. Where the grass cover is not uniform, the rings may not be completely circular, resulting in crescents and interrupted rings. As the fungus spreads outward, it consumes a portion of the organic matter in the soil, much of which is excellent as a food source for the fungus. The soil occupied by a mass of fungus prevents the penetration of water, and consequently the grass in this zone is depressed, goes dormant, or is killed from drought. The centers of rings where grass has been killed may become invaded by weeds if the grass does not reestablish.
Fairy rings survive as spores or as dormant mycelium.
Control begins in the construction or development of the lawn or fairway. Roots, stumps, branches, and other large pieces of organic debris should not be buried. The large pieces of organic debris provide a food source for these fungi. If the only effect of the fairy ring is a stimulation of growth in rings, fertilization will usually take care of the problem. Large holes could be filled with fresh soil free of organic matter.