Grayish-brown to black sunken areas or pits on the
surface of apple fruits are symptoms of a familiar malady known as
bitter pit. This disorder initiates in the orchard. The potential for
pitting is influenced by weather conditions, farming practices and crop
load. Bitter pit can affect all apple cultivars from every area of the
world where apples are grown.
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 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. Simply remove the visible pits and underlying corky tissue with a
paring knife.
Bitter pit symptoms can be seen in the orchard before
harvest but generally only 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 fruit with
pits before packing the fruit for sale. However, bitter pit may
occasionally develop following packing 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 Dr. Mike Willett, Vice President for
Scientific Affairs, at (509) 453-3193 or email at willett@nwhort.org.
