One of the best peach trees I ever had came up volunteer in the kitchen refuse pile of the old schoolhouse on my farm. An older lady had been living there and she piled up all table scraps in this pile.
I've had several others come up in fence rows over the years but most never amounted to much.
My failure to spray regularly has resulted in a blight and brown rot in the last several years peaches. At this point, I do not think even spraying would cure it.
Our humidity and abundance of cedar trees makes growing tree fruit difficult here.