Those who grow peaches commercially have a regular schedule of sprays. You can check with your local university extension agent to see what they recommend. You also could apply an insecticidal soap/horticultural oil spray on the tree right afte r the flowers drop off and the fruit starts to form. Use this conservative spray again two weeks later--spray the entire tree. Watch for moths,the adult forms of the worms. Spray again if you see a number of them. The alternative is to simply cut the worms out of the fruit.