Here’s a close up on the subject of my question below. This one was taken from up high, where it seems slugs would be unlikely to venture. I’m also not seeing any snails or slugs on the trunk or branches. I picked up some PBR to lure them away, just in case.
revelgardener 
I used to have a peach tree in the yard years ago when I lived in Brooklyn. All I remember about bugs on it was the occasional worm in a ripe peach. My father would dry out large peach pits, then drill a hole through the middle of them with a hand drill. Then he would file a flat spot on one side, shape the rest and make a finger ring for us kids.
Back from memory lane to the bugs…
About all I can think of is check the bottom side of the leaves and look for anything that looks like a bug, or bug eggs. If you find anything like that try to get a close picture of it. Either way, get the leaf picture you posted here and send it to this website http://www.TheSelfSufficientGardener.com
It’s a good gardening website with a lot of good podcasts. Jason periodically does a show on bugs, and welcomes pictures people send him for identification of unknown critters. He believes in gardening without chemicals and treats the garden as an ecosystem that needs to be in balance rather than drowned with chemicals. I’ve learned a lot from his podcasts.