Apple: Bitter pit

Biology

Bitter pit of apples is a physiological problem which results from calcium deficiency in the fruit. Depressed spots appear on the fruit surface and the tissue beneath the spot becomes brown. The spots may be up to 1⁄4″ in diameter and are most often seen near the blossom end of the apple. Later, the spots will become sunken and somewhat dry and corky in texture. Several cultural practices can increase the occurrence of bitter pit. Heavy pruning and large nitrogen applications result in vigorous shoot growth and increase bitter pit. Irregular watering, drought stress, and hot summer weather can also contribute to the problem, as will injuries to the trunk or roots which interfere with water and nutrient uptake. Certain apple varieties are more prone to this cultural problem.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Plant resistant varieties such as ‘Delicious’ and ‘Winesap’ when practical (these varieties may be susceptible to other problems). The variety ‘Buckley Giant’ is extremely susceptible to bitter pit.
• Avoid heavy pruning and other practices which result in vigorous growth.
• Fertilize properly. Avoid excessive nitrogen applications.
• Maintain a constant soil moisture supply.
• Avoid injury to trunks and roots.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended.