Fungus Gnats in Houseplants

Fungus gnat on the side of a pot. Photo by Laura Iles.

Do you ever notice the occasional small fly in the sink, or sometimes on the lighted screen of a laptop in the evening? Possibly a few dead flies on the windowsill?  There are several species of flies that breed in homes, but one of the most common are fungus gnats.  These flies get their name from the fact that the larvae feed on fungus growing in decaying organic matter. 

The most common breeding area of fungus gnats in homes or apartments are houseplants.  Especially houseplants that are overwatered.  Letting soil dry between waterings will help reduce fungus gnat problems.  You can usually figure out which plant is the culprit by watching the soil surface closely when you water.  If you notice small flies running on the soil and up the sides of the pot they are likely breeding in that soil.  Repotting the plant with new soil will also help solve the problem.

We do not recommend insecticides as they are not necessary and they are not effective for fungus gnat control in houseplants.  Click here for more information and pictures of fungus gnat larvae. 

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