Sooty Canker - Sooty Canker Fungus Disease

Sooty canker, also known as branch or limb wilt, is caused by the fungus, Hendersonula toruloidea. This wound pathogen invades only sunburned bark or areas that have been mechanically injured, such as pruning wounds on smooth or thin barked deciduous trees. The fungus does not infect uninjured host tissue. In Arizona, disease is found primarily at low elevations where sunburn damage commonly occurs on trunks and branches of unprotected or stressed shrubs and trees. The fungus has a wide host range and causes diseases in many unrelated plants.

Symptoms: The most common symptom of sooty canker is the sooty, black canker that develops beneath bark tissue. This black canker is due to the presence of masses of black, fungal spores that appear under the bark and on the surface of the canker. Symptoms on leaves of cankered branches appear during summer. Because the fungus grows into and kills sapwood, the leaves on branches with cankers, wilt, turn brown and die. Branches die back to the cankered area. Scattered branches are usually affected. Most cankers develop on unshaded trunks or limbs that face toward the sun. Sunburned trunks and limbs are highly susceptible to infection.

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Publication adapted by Mary Olsen, Plant Pathologist
Updated from a publication originally written by Richard Hine, Plant Pathologist (retired)
Revised May 1999