Q.Nectarine tree
My nectarine tree has stopped producing fruit. Three years ago it produced hundred of nectarines.
This year there is one nectarine on my tree. Last year wasn’t much better.
It looks healthy. Leaves are healthy. We spray for leaf curl every December-January. What happened?
I would first encourage a soil test. This will help you determine what nutrient issues the tree may be having.
Your local County Extension Office can help with a soil test.
These links will help you pinpoint the cause.
https://extension.psu.edu/plants/gardening/fact-sheets/home-orchard-production/why-is-there-no-fruit-on-my-tree
https://www.gardeningknowhow.com/extension-search