WSU Tree Fruit Research & Extension Center

Tree Fruit Market Diseases

Saturday, February 16, 2019

WSU-TFREC/Postharvest Information Network/Tree Fruit Market Diseases/pearpink

Cephalothechim roseum Cda.

Pink mold rot of pears, like the same disease on apples, is no longer a problem, but it is included in this publication because it may be confused with other pear rots.

Early stages of the disease appear as small, irregularly shaped spots with brown margins and light centers. White fungus threads may develop on the surface of the lesions, and under moist conditions they may also be accompanied by pink masses of spores. A second stage consisting of chocolate-brown, irregularly shaped, sunken lesions up to 2 inches across may develop under favorable conditions. Depressed, lighter colored, circular spots may be scattered over the surface of the rotted areas. The late stage of the rot is less likely to exhibit the white fungus threads and pink spore masses than the first stage. At any stage the rotted areas are rather firm and dry, or at least, not watery, and the affected tissues have a bitter taste.

Superficially the early stage of pink mold rot resembles bull's-eye rot, but it can be distinguished by the irregular shape of the lesions and by the presence of the white fungal threads and pink spore masses. The pink mold fungus is a shallow-growing organism, rarely penetrating more than 1/8 inch into the flesh. Bull's-eye rot lesions are round or elliptical, the fungus penetrates more deeply into the flesh, and the affected tissues are mealy.

The bull's-eye rot organism grows slowly at 32 °F, while the pink mold rot organism is almost entirely checked at this temperature. Control of pink mold rot, therefore, is best obtained by refrigeration.

No photos available for this section.

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