Calyx end rot

Disease

Calyx end rot

Sclerotinia sclerotiorum (Lib.) de Bary

Distribution: Common to all fruit-growing regions in eastern North America.

Photos

Lesions tend to form to one side of the calyx.

Lesions tend to form to one side of the calyx. Thomas Burr, Cornell Univ.
A

Symptoms begin at the calyx end of the fruit, causing a reddish discoloration at the site of infection. The rot is at first soft, but eventually dries out, turning tan to brown with a red border. Calyx end rot is caused by the "white mold" fungus. Infected fruit have a tendency to drop prematurely.

  • Crops Affected: apples

    Management

    The disease is relatively uncommon and occurs only in seasons when wet and cool conditions occur during bloom and petal fall. It does not spread to other fruit once symptoms appear. Generally, practices employed to control other diseases will keep it from becoming economically damaging.

    Similar Species

    Dry eye rot is caused by the "gray mold" fungus. The two diseases are often confused with each other and may also be confused with blossom end rot infection caused by black rot. Usually, isolation of the pathogen is necessary for positive identification. One field characteristic, however, is that calyx end rot lesions tend to form to one side of the calyx (A), whereas dry eye rot lesions are centered about the calyx (B).

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