Expert Problem Solver

Sooty Blotch

Sooty Blotch
Tap to view larger image
Bonide Solutions:
 
Sooty Blotch is a disease caused by several unrelated fungi. It consists of irregularly shaped olive-green to dull black smudge-like blemishes. Sooty Blotch lives above the skin of apple fruit, in the protective layer of wax. The fungi develop in the wax, using the apple juice that seeps through the skin as nutrients.
Sooty Blotch overwinters on twigs of various wild woody plants, especially wild blackberry and raspberry canes. Growing raspberries or blackberries near apple trees increases the risk of sooty blotch. Try to keep apples and brambles as far apart as possible.
It is most common in the damp, low, shaded areas of the orchard. Any practice that promotes faster drying of the fruit greatly aids in control. For example, prune trees annually to have an open center for maximum air circulation and thin fruit a few weeks after petal fall so there is only one developing fruit every six inches.
Remember that sooty blotch is trivial and generally does not impact the quality of the fruit. Remove by washing, rubbing, or peeling the fruit as this results in fruit that is more suitable for eating or cooking.