I use an orchard spray. It has fungicide and insecticide all in one so easy. I have used this one below. You have to do it religiously, like every 2 weeks, to get good results. Pruning is very important with all fruit trees to get good results too.
http://www.gurneys.com/product/fruit...FZRr7AodBUAAgQ
Peaches are very susceptible to fungus of many variety's much more than insects. But hard to say what specific one you have. I used to have about 7 peach trees but down to 2 now. Peaches are not very long lived fruit trees, unlike apples. Nothing better than a home grown tree ripened peach and peach jam. You could eat around the blotches as I had the same problem too but really doesn't affect the fruit taste wise. Nothing wrong with some imperfections on your fruit. Heck I would even eat peaches if they had a few worms in them as they would usually be around the pit and not the flesh going in from the stem. I would just bust the peach open and discard the pit and worms. The flavor is so good it is well worth it. People are spoiled by perfect looking fruit, which usually have no taste at all. I'll take an ugly good tasting fruit over a pretty one any day.
Reading this may help you. But you could use the orchard spray for the peaches too.
http://homeguides.sfgate.com/fungici...ree-64168.html