Q: I have all these black gnats or some kind of small fly in my house and I did not have them before I brought some of my plants in for the winter, they are driving me crazy but are they some thing that I need to be concerned about for my plants and if so what do I need to stop them?
A: What you have are called Fungus Gnats and the adults that are what you are seeing and are so annoying. The adults are of no danger to the plants and are only a nuisance for people. The larvae are the problem. The adults fly around looking for moist wet soils to lay their eggs in that then hatch into tiny larvae that feed on organic mater in soils and sometimes plant roots. The most effective treatments that I can recommend are to water only as needed, allow soils in plant containers to be almost dry before watering. Check the soil with your finger to a depth of several inches into the container before just pouring the water on. There are some houseplant sprays that you can use on or around your houseplants if you have a major infestation. Also there is a product called Systemic Insecticide Granules that you can sprinkle onto the soil in the containers and as you water it dissolves and will help to kill the larvae in the soil before they can develop into the adult gnat.