It is called Coryneum Blight or "shot hole" disease.  It is a fungus that infests during cool, wet springs.  It first forms dark spots with brown centers on the leaves.  These centers eventually fall out, leaving a "shot-hole" appearance.  The fruit has rough, corky blemishes with a red ring around the spot.  Control includes: keeping leaves and fruit dry from sprinkler spray, proper pruning, maintaining good tree vigor and a fall clean up of debris around the base of the tree.  A fungicide maybe applied in the fall after all the leaves have fallen, again in the spring at pink bud stage, full bloom and when leaves begin to appear.
Reference: “Coryneum Blight of Stone Fruits”, at http://extension.usu.edu/plantpath/fruit_diseases/fd_coryneum_blight.htm