I doubt your fairy ring is damaging your lawn. It is so extensive that you
would have noticed the damage by now during an earlier stage of its growth.
Some fungi even seem to feed the lawn - the ring area is greener than the
rest of the lawn. However, your fungi are larger than those I've seen in my
lawn, so I would advise removing them by hand.
As far as I'm aware, there is no preparation you can use to remove/kill
fungi these days .. perhaps someone else can help there.
Fungi aside, it's certainly worth treating your lawn to a
scarifying/aerating/feeding regime. IF the fungi were capable of weakening
your lawn, good health would give it a fair chance of fighting back.
Spider
Pen Phill wrote in message
...
Hi all

Its mushroom season here in Brittany and over the last few days a nice
large
Fairy ring (one of several) has developed in the lawn.

http://members.aol.com/penphill/ring1.jpg

I don't mind it all that much but the grass has already suffered from this
years drought. Does anyone know if the mycaelium inside the ring, which is
about 7m across does any damage to the grass above it. I read that such
rings
continue to steadily grow for years......

Phil