Everything is just fine – You’ve been diligently watering your plants, they look healthy, lush, and beautiful but you notice a yellow leaf near the bottom of your peace lily. As you reach in to cut off the yellow leaf a cloud of small gnat-like bugs swarm around your arm. Ack! What are these horrible little bugs? Are they killing my plant? What are they doing here? What you are seeing is most likely to be one of the most common house plant pests: fungus gnats.

What are they?

Fungus gnats are tiny flies that buzz around the soil surface and lower leaves of your plants.

What do they do?

Not much other than fly around and mate but the grub-like larvae of this insect squirm around in the soil eating roots and other assorted things living in the soil environment.

Where did they come from?

If it’s new it could have been living in the soil when you purchased the plant. Many times the sprays used on plants in greenhouses only kill the adults because the larvae go untouched below the surface of the soil.

How can I get rid of them?

You can get rid of these little flies by doing four things.

1) Put out sticky traps like Gnat Stix to catch the adults.

2) Remove the top ½ inch of soil. This is where most of the larvae live.

3) Keep the surface of the soil dry for a few weeks. It helps to “water from the bottom” which can be done by placing the plant in 2” plastic drip tray, only pouring water into this tray and allowing the plant to soak up the water from the bottom.

4) Apply Bonide systemic insect control to the soil surface as directed.

* Photos from the UofF. To learn more about fungus gnats go to the University of Florida Fungus Gnat page.