MSU Extension Integrated Pest Management

Moldy core and core rot

Disease

Moldy core and Core rot

Alternaria spp. Cladosporium spp. Epicoccum spp. and others

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

---

Moldy core is associated with several different fungi. Infection is initiated at the calyx end and the fungi proceed to grow inward into the carpel tissue or locules and cause a core rot. External rot symptoms are rare. Fruits ripen early and decay is only obvious when fruit are cut in half (A, B). Core rot appears similar but occurs after harvest when the fruit are dipped into contaminated water in the packinghouse. A wet rot develops once the fruit are in storage.

• Crops Affected: apples

  Management

  These diseases are important on varieties with an open sinus extending from the calyx to the core, such as Delicious and its red sports. Fungicides applied at bloom may reduce incidence of moldy core.

  Similar Species

  This disease can be confused with blossom end rots.