There are no treatments available for Peach Leaf Curl - but this infection generally occurs in a wet spring. Not sure where you are, but here in the south, its been anything but wet, in fact, we're bordering on drought conditions. If you're sure its Peach Leaf Curl, then the most effective 'treatment' is prevention in the form of covering the plant from November onwards - see link for description of Peach Leaf Curl, general information and how to erect protection
https://www.rhs.org.uk/advice/profile?PID=232