Could it be getting too much water? Our area has been getting a lot of rain and very hot temperatures this year. We live in northeast North Carolina. Our very young apricot tree is losing its leaves and looks more like it should if it's fall rather than the middle of summer. It gets sun in the morning and early afternoon then is in the shade.
Apricot Tree Is Losing Its Leaves
Certified GKH Gardening Expert
Too much water could be the culprit, but if it is getting too much water, it would have to be in standing water. If the grounds around the tree is swampy, this could be the culprit.
More likely, with the rain and heat, it has a fungus. Most fungus the defoliate a tree are not normally lethal to the tree, but it does make them look unsightly. I would recommend treating the tree with a fungicide and that should clear it up.