Question
Hi there,

You can see by my name why I picked you!  Anyway, I have several plants in a medium size office that have flies or gnats in the soil.  I have not seen them on the plant leaves, only in the soil and the air.  They have a black body or dark body with see through wings and no sticky or waxy residue, so white flies didn't fit their description.  I do not want to use pestisides, something soap based or natural is preferred.  I took a ficus tree home that had scale and flies in the soil also that is dropping about 20-30 leafs a day.  Scale I am picking off and using soap/water spray.  Any help with the flies?

Thank you so much,
Krista Little

Answer
Krista,

They are fungus gnats and are there because your plants are overwatered &/or the soil has too much peat moss and is holding water too long so the roots don't have a chance to breath carbon dioxide through the soil between waterings so the roots begin to rot just as though they are sitting in a swamp. The rotting roots attract the fungus gnats. Let the plants dry out more between waterings and the gnats will disappear. Next time you repot those plants go to your nearest garden center and buy a bag of perlite and a bag of horticultural charcoal. Mix 2 parts potting soil with part perlite and i/4 part of horticultural charcoal. That will make the soil more porous and hold more air so the roots will not rot and attract the fungus gnats.
You can also flick the scale off the plant using cotton swabs dipped in rubbing alcohol.
Good luck.

Darlene