Symptoms

• Black rot is a firm-textured rot. The spot at first is light brown but darkens with age.
• A circle of raised dark postules are formed in the center of the spot. Infected leaves are covered with many small purple specks.
• At maturity the spots are purplish cast with brown centers. Twig infections are small, sunken, reddish-brown areas.
• The organism overwinters in cankers, decayed fruit, and dead wood. In the spring spores are formed in the cankers.
• Leaves are the first tissue to be infected. A temperature of 80 degrees F. and rainfall encourage disease development. Infection generally takes place at the blossom end of the fruit as it reaches maturity.

Management

• Sanitation is one of the more important means of control. Remove all dead twigs, limbs, and decayed fruit.
• Fungicides must be applied when the fruit is beginning to expand in the spring.