The fungus Armillaria ostoyae, commonly known at root rot, has become the world's largest living organism thanks to an outbreak in Prairie City, Ore.

Currently the fungus form dubbed the "humungous fungus" by the U.S. Forest Service underlies 2,200 miles of land outside the Oregon city and wildlife officials are at a loss how to stop its growth, The (Portland) Oregonian said Sunday.

With some estimates placing the fungus' age at 8,000 years old, the natural organism has had plenty of time to spread throughout the region as other life forms unknowingly moved above.

To that end, the fungus now spreads across an area equal to 1,600 football fields and is only noticeable in areas where it has claimed trees.

Experts predict the massive fungus may lose a significant portion of its mass as the victim of a major nature fire.

The Oregonian said the record-setting organism lost a portion of its bulk to a fire four years ago.

Copyright 2007 by United Press International