Fairy ring is caused by a fungus which actually is active during the fall of the year. In Atlanta we usually see this disease on zoysia lawns though it can occur on other types of warm season turf. The Spring exhibiting symptoms are brown areas in the turf which can resemble circles, arcs or streaks. We traditionally do not see the classic ring with mushrooms but we do see large rings, squiggles and arcs.
Treatment for this disease must be applied in the Fall with one application in October and a second application in November. There are limited fungicides available for treatment of fairy ring and the applications are costly.
If symptoms appear in the Spring, the area should be aerated to open up the soil then flushed with water to reduce the toxin levels. Recovery during the year can be very slow. Even after treatment you may still have symptoms as the treatments are extremely variable as to their efficacy. The fungal spores can lie dormant for years; one year you may have it then the next year it will not appear. Without treatment in the Fall it can become severe so treatment is recommended even though it is not 100% effective.
UGA has additional information on Fairy Ring at http://pubs.caes.uga.edu/caespubs/pubcd/B1233.htm#FairyRings
