Just curios, Amigatec, do you have standard or dwarf cherry trees
Cherries are prone to bacterial gummosis, brown rot, cherry leaf spot and leaf curl.
Dormant oil spray [not copper sulfate and lime] which can control the leaf curl also will take care of mites and scales. This spray is applied during dormant period.
Is it a true leaf curl or leaf wilt due to lack of water? Water should be applied as soon as the top 3 inches of soil is dry; the water should be run long enough to soak down 4 ft.; this usually means a 2-hour soaking from a trickling hose whenever a dry spell last longer than 2 weeks. If the soil is sandy, use less water, but water frequently. If the soil is clayish, the interval between watering is a little longer.
I have several dwarf cherry trees
in containers. The leaves curls also, and not because of leaf curl, but as a protection /first defense to conserve moisture.