Question
I have an office ficus that is overtly in good health, although there is an ongoing problem throughout the office with gnats.  Through careful monitoring, as well as applications of pesticides to all 3 plants, I've reduced the amount of these and traced them to my ficus.  However, these treatments aren't ending the problem.

There are lots of gnats, but no little larvae/worms in the soil.  Thus I suspect that these are not fungus gnats.

The ficus has a number of large (1-1.5") galls at the area where the trunk meets the soil, and I suspect the gnats are coming from there.

What kind of pest is this, and what should I do about it?

Answer
Jessie, The gall is a commond occurance on Ficus Benjamina, so I don't suspect that to  be the source of your infestation; I'm not sure what kind of insect it is without being able to see it, but I suspect it could possibly be whitefly, a common indoor pest of most house plants and very hard to control because of their flight habits; all I can suggest from the limited information I have, is if you truly believe the ficus to be the source, then take it out of the office (if possible) and repot with new potting soil and continue to spray oil on the leaves; another suggestion is when the office closes, you may set off a fumigator, and the next day air out the office for about an hour, this should eliminate any adults lingering about....good luck..Nick