Question
I SAW YOUR RESPONSE ABOUT BUGS ON THE LEAFS OF FICUS.  THESE ARE BLACK BUT THEY ARE IN LEAFS THAT ARE FOLDED IN HALF AND OF COURSE START TO TURN YELLOW -  WHEN YOU OPEN THE LEAF THERE ARE LOADS OF LITTLE BLACK BUGS THAT DEFINITELY MOVE.  I TRIED SEVIN BUT IT DIDN'T WORK OF COURSE I'D RATHER HAVE SOMETHING NATURAL IF THERE IS SUCH A THING.

Answer
They could be aphids or some other leaf roller type insect.  The sevin should have worked, provided you got contact with the insects.  That is why they roll the leaf, to protect them from predators.  I dont know of a natural product that will kill them, but there is a safe product you can use. I would treat the plant with Bayer Advanced Tree and Shrub Insecticide.  This product is mixed with water and poured on the soil around the base of the plant.  It is taken up systemically and will kill the bugs within a week or so.  It also provides protection from reinfestation for up to a year.  This product is good stuff.  I hope this helps fix the problem.  Good Luck.