A Technical Information Bulletin
of the
Northwest Horticultural Council

Bitter Pit

Grayish brown to black sunken areas or pits on the surface of apples are symptoms of a physiological disorder known as bitter pit. This disorder is initiated in the orchard, with symptoms typically appearing in storage. Bitter pit can affect all apple cultivars from all growing areas, but is more common on the varieties Cortland, Gravenstein, Honeycrisp, Northern Spy, and York. Cultivars that exhibit resistance are Delicious, Gala, and Winesap.

Bitter pit is not caused by microbial pathogens or insects. It results from a calcium deficiency and is influenced by soil moisture, weather conditions, crop load, and increased levels of nitrogen and potassium. This leads to 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. A similar calcium-related disorder that occurs only on D’Anjou pears is named cork spot.

While symptoms can be seen in the orchard before harvest, they generally become 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. Although it does not impact the safety of the fruit, bitter pit is considered unattractive and can detract from edibility.

Bitter pit develops most quickly when the apples are stored near 50 degrees Fahrenheit. Cold storage at temperatures near 32 degrees Fahrenheit inhibits the development of pitting. Research has demonstrated that controlled atmosphere (CA) storage established during conditioning can reduce apple bitter pit development without inducing other physiological disorders.

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, contact the NHC at 509-453-3193.

Updated 2/6/2023