Q.Fruit tree canopy thinning and leaves wilting
We live in Louisiana. We have a large backyard with multiple trees, two of which, a Meyer lemon tree and a Blood Orange tree, planted about ten years ago, have been bearing lots of fruit. We fertilize them regularly with fish-based fertilizer and compost. Unfortunately, this year, their canopy has been thinning and their leaves have been curling for no apparent reason (they are well-watered by the rain and we fertilize them). Grey blotches are also appearing on their trunks, especially visible on the orange tree. The harvest also promises to be much smaller than last year’s for both trees. We can’t figure out what’s wrong with them or what to do. Any advice? Thanks in advance!

Leaf curl is a sign of either pests, disease or environmental stress.
The article below will help you pinpoint the issues.
https://www.gardeningknowhow.com/edible/fruits/citrus/curling-citrus-leaves.htm