University of California

Fruit Physiological Disorders

Pear: Flesh Spot Decay



Japanese pear cultivars such as ‘Shinseiki,' ‘Nijisseiki,' ‘Kikusui,' and ‘Hosui.' FSD is more frequent on large size (300 g) and overmature fruit.

FSD limits opportunities to grow and market Japanese pears.

Partial browning of spots and/or development of cavities in Asian pear flesh. It appears along and around the vascular bundles when the symptoms are severe, but there is no external indication of the disorder. Generally, FSD is more pronounced above the equator of the fruit (towards the stem end), but it can also be observed all the way down to the calyx. Cavities are usually dry and surrounded by apparently healthy tissue. This disorder can occur in fruit while still on the tree. It is more obvious, however, after 2-6 week cold storage.

The cause of FSD is still unknown. However, climatic factors, such as a fluctuating hot and cool summer, or high rainfall right before harvest may enhance the incidence of this disorder.

There is no effective way to control FSD since definite causes have not been identified. The problem is the inability to predict or diagnose FSD without cutting the fruit. Further research needs to be done to determine the causes, variety susceptibility in local climates, and other control methods either pre- or postharvest that will reduce FSD symptoms to a commercially acceptable level.

Meanwhile, avoid whenever possible the following conditions that might induce FSD: low crop load - large fruit; later picking - advanced maturity; extreme temperature changes during the maturation season; sunburn; erratic irrigation or precipitation - frequency, amount and timing; harvesting fruit under warm temperatures and cooling the fruit rapidly.

Griggs, W. and B. Iwakiri. 1997. Asian pear varieties in California. Univ. of California DANR Publ. 4068, Oakland.

Lallu, Nagin. 1990. Fruit growth, handling and storage, p. 53-74. In A.G. White (ed.). Nashi, Asian pear in New Zealand, DSTR Publishing, Wellington.


1997 & 1990

Use of Materials

The UC Postharvest Technology Center grants users permission to download textual pages (including PDF files) from this World Wide Web site for personal use or to reproduce them for educational purposes, but credit lines and copyright notices within the pages must not be removed or modified.

Except for these specified uses, no part of the textual materials available on the UC Postharvest Technology Center Web site may be copied, downloaded, stored in a retrieval system, further transmitted or otherwise reproduced, stored, disseminated, transferred or used, in any form or by any means, except as permitted herein or with the University of California's prior written agreement. Request permission from UC Postharvest Technology Center. Distribution for commercial purposes is prohibited.

Links to any of these UC Postharvest Technology Center pages are permitted, but no endorsement of the linking site or products mentioned in the linking page is intended or implied by such a link.

How to Cite

Author(s) names. Initial publication or update date (located at the bottom). Title. Link to the specific Fruit Physiological Disorders webpage (Accessed date)

Example: Mitchell, F. G., G. Mayer, and A. A. Kader. 1980. Injuries cause deterioration of sweet cherries. California Agiculture 34(3):14-15. (Accessed January 18, 2014).

Top of page


Webmaster Email: