Hi,
Look for midges/gnats. Ants carry them and the midges will sting the fig trees for feeding on the sap ... and you don't want that.
Try and get rid of the ants. I'm using lemons, ashes and used coffee around the trees to kill the ants.
If you find their nest ... Destroy it .
I'm relying on wild ladybugs and lizards to come in and destroy the midges.