I've used Kumulus DF on my fruit trees. Data sheet says it can be used on peaches.

Lloyd

The package should have instructions on it for mixing but if not this brand says to mix 3 tablespoons per gallon of water.
Lime sulfur is normally used as a dormant spray, generally applied in late January or early February although some sources state it can be applied during the growing season in a more dilute mix early in the morning as long as temperatures will stay below 80.

Here is a link that might be useful: Mixing sulfur for spraying