A Technical Information Bulletin
Northwest Horticultural Council
Grayish-brown to black sunken areas or pits on the surface of apples are symptoms of a malady known as bitter pit. This disorder is initiated in the orchard. The potential for pitting is influenced by weather conditions, farming practices, nutrient deficiencies and crop load. Bitter pit can affect all apple cultivars from all growing areas.
Bitter pit is not caused by microbial pathogens or insects. The pits result from a highly localized mineral imbalance in cells just below the fruit skin. Bitter pit is not infectious: it will not spread from one fruit to another.
Although it is considered unattractive, a small amount of bitter pit does not detract from the edibility or safety of the fruit.
Bitter pit symptoms can be seen in the orchard before harvest but generally becomes visible after a period of cold storage. Bitter pit is infrequently seen on produce department shelves because commercial apple growers sort their apples to remove affected fruit before packing. However, bitter pit may occasionally develop during delivery or while in retail market storage. Bitter pit develops most quickly when the apples are stored near 50 degrees Fahrenheit. Cold storage at temperatures near 32 degrees Fahrenheit retards the development of pitting.
The Northwest Horticultural Council represents the deciduous tree fruit industry of Idaho, Oregon and Washington on national and international policy issues affecting growers and shippers. For further information, please contact the Northwest Horticultural Council at 509-453-3193.