What is wrong with my peaches?
What do I need to spray on my tree?
Certified GKH Gardening Expert
This is usually caused by insect damage. Beetles, and flies of many sorts enjoy sucking sap from these fruits.
This collection of articles will give you more information on how to craft your own pest control with ingredients that you likely have in your kitchen already: https://www.gardeningknowhow.com/special/organic