Question
We were recently given a fig tree and the soil is covered with very small knats.  What is safe to use to rid the plant of these knats?

Answer
Hi Sue,

If the gnats are located at the soil line, or hovering just above, what you are dealing with is a fungus gnat infestation.  These are quite common indoors, and are usually nothing to worry about.   The treatment is simple--refrain from watering until the potting medium is dry down to approximately 1 inch.  Fungus gnats feed on soil fungi that are found in soils and potting mixes high in organic compounds.  The fungi need a moist environment for reproduction, and they inhabit only the first  centimeter of soil.  So, if you reduce the watering and allow the soil to dry out somewhat on the surface, that will eventually control your gnat problem.

Others have told me that they use fly paper to help remove the adults, but I have not tried that.  

Be assured that the ficus (fig) will tolerate the drier conditions quite well.  These species make wonderful houseplants because they can withstand so many stresses found in dry homes.

Oh, there is a product called Gnatrol, but it is not effective on all the pupal and larval stages, so the very best way (and least expensive) is to first try drying the soil.  If that doesn't seem to work for you, then you can place the plant outdoors when the weather permits.  The natural predators will soon take care of the fungus gnat population.

Good Luck!