MSU Extension Integrated Pest Management

Peach scab

Disease

Peach scab

Cladosporium carpophilum Thuem.

Distribution: Common to all fruit-growing regions in eastern North America, but is most important in warm and humid production regions.

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On fruit, lesions begin as small, greenish circular spots that gradually enlarge and darken as spore production begins (A). These spots appear when fruit are half grown and are most common on the stem end of the fruit, but can occur over the whole surface. Secondary infections may occur on twigs (B), and late-season variety fruit.

• Crops Affected: peaches

  Management

  Symptoms develop after a very long incubation period of 40 to 70 days. Because of the long incubation period, it is only the infections that occur between shuck split and pit hardening that develop fruit symptoms. Fungicides are typically used to protect fruit during this period.

  Similar Species

  Peach scab can be confused with bacterial spot infections, but can be differentiated by the presence of dark green sporulation.