Nectarine Tree Is Slowly Dying

Question

A large branch, about 20% of the tree, with developing fruit has died and another is dying. What to do?

Answer 1

Without a description of how long it took between the branch looking stressed and the actual branch death, whether or not the leaves are wilted or brown, whether or not the twigs break with a sharp snap or merely bend, is there life in the cambium layer when the bark is scratched, what size is the branch, how old is the tree, has it had an injury, has the tree been stressed...need more information.