I am not an expert but my history with curl was to use 45-0-0 let the tree push through the curl and still give good fruit and come back. Take this as a newbee whithout Hmans knowlage.

Peter:

The only effective treatment is during the dormant season, Nov to Febr or March. Right now all you can do is try to grow new leaves as suggested. Also pick up and destroy damaged leaves.

I am new to fruits. I planted my trees 2 years ago. Without knowing, I planted an Elberta peach in rainy Portland Oregon (stupid, I know). I sprayed a sulfer type spray on all my trees in the fall, then a copper based one on the peach in February.

I live in RAINY DAMP Portland and my peach tree has ZERO leaf curl issues. That's right, no PLC. I am starting to wonder if controlling PLC is as easy as a late winter application of copper. Or could it be that my tree was a mislabeled resistant variety? Surly I would have at least ONE affected leaf?
(other peach trees in the neighborhood are COVERED in PLC)

I vote for feeding your tree and letting it push through the PLC. Then spray it with a copper spray in late winter before it leafs out, and maybe in fall for good measure.

Management is via spray during dormant season.
No soil treatment available.

Hi
Does anyone know the names of any leaf curl resistant peach or nectarine trees?
Peter

Redhaven is tolerant. Some others are described in the link too.

Here is a link that might be useful: UC Davis on Peach Leaf Curl with Tolerant Varieties