How to Manage Pests

Pests in Gardens and Landscapes

Sappy bark—Trametes versicolor

Sappy bark, also called papery bark, is a minor fungal disease of apple that occurs on older trees in most growing areas. The sappy bark fungus enters limbs and larger branches at pruning cuts. Infected bark and wood tissues decay, becoming spongy and discolored. Affected bark frequently peels away, exposing decayed tissue beneath. During damp weather, affected bark appears spongy; when it is dry it looks papery. Dark sap sometimes oozes from diseased areas. Bracketlike, spore-producing structures may form along the edges of affected areas. Sappy bark cankers can girdle branches, or if infections are located on the trunk, they can girdle and kill the tree.


To reduce the incidence of sappy bark, maintain your trees in good vigor and always make pruning cuts flush with the limb. Leave no stubs when pruning; these can be invaded by the fungus. If diseased bark and wood are present in the tree, cut them away and destroy.

Peeling of bark
Peeling of bark

Statewide IPM Program, Agriculture and Natural Resources, University of California
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