Tree Fruit Research & Extension Center

Cullage Assessment & Education

Quick Identification Guide to Apple Postharvest Defects & Disorders

Postharvest Diseases

The Diseases section of the card set includes all the major fungal diseases found in stored Washington apples. This section also includes a Symptom Comparison Table to help. At a later date more cards may be developed for this section which would include any newly discovered pathogens. For ordering information visit the Order Information section of the Introduction. The cards shown on this site are slightly modified to accomodate web formatting. Figures may appear fragmented in some browsers. Please report viewing problems here. Any reproduction of the card images or content without permission is in violation of WSU Copyright policies.

Postscript:  Since the publication of this card set, a new fungal disease was discovered and identified, Phacidiopycnis washingtonensis, AKA Speck rot. This fungas has become a serious quarantine pest for some export markets, such as China. Dr. YK Kim and Dr. CL Xiao, both formerly of WSU, fully describe this disease in their paper found here. Although not found in the printed card set, we have included a description of this disease with the other fungal disease below.

 

 

DISEASES: Blue Mold  

Blue mold symptoms

Blue mold (primarily Penicillium expansum) is a very common postharvest fungal disease on apples worldwide. This disease is of economic concern to both the fresh-fruit industry and the fruit-processing industry because some strains produce the mycotoxin patulin, which can rise to unacceptable levels affecting the quality of apple juice.

Figure 1: Blue mold originating from infection of wound on fruit; decayed area brown, soft, and watery, with a sharp margin; blue-green spore masses visible.
Figure 2: Blue mold decayed tissue is completely separable from the healthy tissue.
Figure 3: Blue mold originating from infection of wound on a Granny Smith fruit; spore masses formed at the infection site.
Figure 4: Calyx-end blue mold on a Fuji fruit; usually associated with drenched fruit.

Blue mold symptoms
Blue mold symptoms Blue mold symptoms

 

 

 

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