Problem Identifier Unit Screen//v.w/ RR Template

Problem Identifier Unit Screen//v.w/ RR Template Bitter Rot

Problem
Sunken, light brown, circular spots appear on the half-grown fruit. These spots gradually enlarge to 1 inch in diameter. Concentric rings and sticky pink masses of spores may appear on the spotted areas during moist weather. The rotted apple flesh tastes bitter. Sunken lesions may form on the branches.

Analysis
This plant disease, which also affects pears, is caused by a fungus (Glomerella cingulata). The fungus spends the winter in rotted apples left on the tree and on the ground, and in sunken lesions on the branches. Spores are spread by splashing rain to healthy apples in the spring. Infection can occur throughout the fruiting season. In areas where hot, humid conditions last for long periods of time, bitter rot can quickly destroy an entire apple crop. This disease primarily attacks the fruit, and does not severely damage the health of the tree.

Solution
Spray infested trees with a fungicide containing captan. To prevent recurrence next year, prune out and destroy branches with lesions, and remove and destroy rotted apples. Next spring, spray the trees with captan just before the blossoms start to open. Continue spraying according to label directions. Plant resistant varieties (see Apples).

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