Some rings disappear for a year or more and then reappear. Fairy rings may be produced by 50 or more species of soil-inhabiting fungi. The dark green grass is largely due to the increased amount of nitrogen that is made available to the grass roots by the fungus as it breaks down organic matter in the thatch and soil. The ring of brown or thin grass develops largely as a result of drought stress caused by the dense growth of fungal material. This weakened grass is more susceptible to environmental stresses, disease, and weed invasion.
Fairy rings are usually most severe in light-textured, low fertility soils low in moisture.
The mushrooms grow on decaying organic matter and are most likely to form in turfs with a thick thatch or in areas where trees have been removed. Control of fairy rings can be difficult. Symptoms may be suppressed by pumping large quantities of water on either side of the stimulated zone of dark green grass. A light fertilizer application during the growing season will reduce the contrast in green color between the fairy ring and the rest of the turf. Fairy rings can be physically removed by digging out the sod on either side of the dark green ring of grass and replacing it.