Posted: 08/09/2014 at 19:26
Fungi are one of the few living things which can break down woody matter (mainly cellulose) into a form which plants can re-use. They are an essential part of the cycle of life. If all fungi died-off right now, life would quite soon come to an end on the land (it would probably continue in the sea though.)
The parts we usually see (mushrooms or toadstools) are just the fruiting body and only a tiny part of the main fungus, which is known as mycelium and lives in the soil or inside other living things (for those species which are parasitic.)
If toadstools are a nuisance on a lawn you can just sweep them off with a stiff brush - the main body of the fungus won't be killed by doing that.