My potted fig tree also defoliated in March but returned to perfect health with daily watering. Fig trees cannot be allowed to dry out. Probably the hot weather will cause your tree to drop all its leaves unless you keep the ground moist.

Figs get so few problems that it is most likely a water problem. They are water hogs!!! I agree with palmcityfl, about the water. (Overfertilizing could also cause problems.)

Christine

I had a terrible problem with tiny brown spots on every fig leaf for the longest time. Some sort of fungus, I suppose.
During the Big Freeze, all the leaves fell off my fig, then when it started greening up a few weeks later, I was ready with my spray bottle loaded with copper fungicide. I sprayed the new leaves very aggressively on several occasions, and everything is looking terrific now.

Oh, yes, I did forget to mention the rust fungus that they get in the fall (in my area). I ignore it because it shows up after the fruits are harvested. Brute, if you are getting rust on your leaves before the harvest I can see why you are so concerned. Glad that the leaves are looking good now.

Christine