What causes my peaches to rot and turn brown?
Brown rot is a common fungal disease of peaches and other stone fruits. Affected fruits develop circular light brown spots that expand rapidly and rot the fruit. Sometimes the fungus that causes this rot is visible as ash-gray tufts. The fruits may fall from the tree or develop into shriveled “mummies” that stay attached to the branch.
Brown rot can be prevented through sanitation (removing infected fruits) and avoiding wounding the fruit. Fungicide sprays applied throughout the season, starting at bloom, can also help.