It's spring and my peach tree is full of fuzzy new green peaches. But I see white spots on the small green peaches. What is it and how to treat??
Diseases of Peaches or stone fruits can be caused by bacteria, fungus or virus.
I do think that your peaches may have Powdery Mildew, as this generally shows up on young peaches as small spots, then it spreads. You would also see the Powdery Mildew on leaves.
Inspect the tree for any other evidence to help make a correct diagnosis.
Keep in mind that nutritional issues could also cause some tree and fruit damage.
Here are some articles that will help you.