Peach has black spots on skin, scab disease
Q: We have a lot of peaches this year but noticed they are getting black spots on the skin. Is it too late in the game to treat with a pesticide?
A: A fine description of peach scab disease. The fungus infects small peaches right after bloom. To prevent these “freckles”, The tree must be sprayed every 7 to 10 days with a fungicide such as Captan (click for sources) or Daconil (click for sources).
Do not use a spray that contains insecticide.
Be sure to remove infected fruit that falls to the ground.
The good news is that if the spots are not too dense you can peel the peach and there will be no damage to the flesh underneath.
Get excellent information on other control methods at Homeowner Disease Control.