This decomposition releases nitrate into the soil, which in turn stimulates the growth of the grass at the outer portion of the ring. This results in a dark green appearance of the grass at the margin of the ring. Unfortunately, the thick fungal mat formed by the fungus does not allow for water penetration. The fungus may also release certain byproducts that are toxic to the turf. This can lead to dieback of the turf in the ring.
Fairy rings are difficult to control.
You can sometimes eliminate the ring by digging to a depth of 6 to 12 inches and 12 inches wide on both sides of the ring, refilling the hole with non-infested soil. Alternatively, you can try to mask the symptoms by fertilizing the rest of the lawn so that it is as dark green as the ring. This really isn't a good idea because it tends to promote other turf problems. A couple of fungicides called Prostar and Heritage may help alleviate fairy ring symptoms. These products should be drenched into the affected areas.