Kretzschmaria deusta, commonly known as brittle cinder, is a fungus and plant pathogen found in temperate regions.

The species was originally described as Sphaeria deusta by German naturalist George Franz Hoffman in 1787, and later changed in 1970 by South African mycologist P.M.D.

[1] Kretzschmaria deusta is described as a wavy-edged cushion or crust, ranging in color from grey to white when young, and changing to black and brittle with age.

The inconspicuous fruiting bodies persist all year and their appearance changes to resemble asphalt or charcoal, consisting of black, domed, lumpy crusts that crumble when pushed with force.

[12] The fungus continues to decay wood after the host tree has died, making K. deusta a facultative parasite.

Therefore, the recommended treatment would be to fell trees in areas that may be hazardous and to avoid using the infected plant material as mulch.