Brown Rot on Plums, Peaches and Cherries
Shriveled plums, peaches, apricots and cherries are a symptom of brown rot fungal disease.
This disease can infect flowers causing brown spots on the petals. Infected blooms collapse. They often exude a sticky sap that can spread the disease causing twig dieback. Infected fruit are covered with powdery gray specks. As the disease progresses the fruit dries and shrivels into what are called mummies.
Remove and destroy or bury infested fruit. Prune out diseased branches. Make the cut at least six inches below the sunken or discolored areas known as cankers. Disinfect tools between cuts to prevent the spread of this disease.
Reduce future problems with proper pruning and care. Remove nearby thickets of wild susceptible plums, cherries and other stone fruit that can serve as a source for future infection.
Fortunately, the disease will not kill the tree, but it can greatly impact the harvest.
A bit more information: If brown rot has been a yearly problem despite proper care and sanitation you may decide to use a fungicide to control the problem. Select an organic or synthetic product labeled for controlling this disease on the plants you are treating. As always read and follow all label directions.