Orange Trees in AZ
My orange tree is about 40 yrs old. The last couple of years it has had dying branches but still gave lots of fruit. It bloomed in the spring and then this summer lost all its leaves; I mean every leaf. We get flood irrigation.
Certified GKH Gardening Expert
Many things can cause this, but it's usually a watering issue. This article should help: https://www.gardeningknowhow.com/edible/fruits/citrus/leaves-falling-off-citrus-tree.htm