Scorched Plague

The Scorched Plague is caused by a fungus found underground in Appalachia in 2102.

Background
Research logs at Arktos Pharma seem to suggest that the Scorched plague was created by them before the war. Whether it was designed as a disease or accidently created as a byproduct is currently unknown.(source?)

The Scorched Plague is spread by a fungus found underground in Appalachia. It was spread to the surface by scorchbeasts and was influential in creating the Scorched, causing crystalline green growths in the latter.

The plague is responsible for the destruction in one way or another of every human faction that had existed in Appalachia, from the Responders and Free States to the Brotherhood and Raiders, even the Enclave sealed in their bunker beneath The Whitespring Resort succumbing to it.

Appearances
The Scorched Plague appears only in Fallout 76.