Fungus Gnats

What Are Fungus Gnats?
They are tiny black flies.

Do they harm plants?
No, but they are a real nuisance. If you have had them, you know they like to fly up your nose and into your mouth. I get them here at the office, especially with my African violets.

So why do they infect house plants?
It's simple: they love moisture. If your houseplant stays wet, the larvae will thrive, especially in the top two inches of soil.

So how do you get rid of them?
You need a two-step approach: first, kill the adults that lay eggs, and second, get rid of the larvae in the soil.

1) There are several ways to get rid of them. Start by keeping your houseplants a bit drier, especially in winter. Let the top one to two inches of soil dry out before watering again.

2) You can also use yellow sticky traps. I use them in the office, and they really help get rid of the adults.

3) Bonide systemic - This is a systemic that is absorbed through the roots of the plant and goes into the leaves. It will kill the larvae in the soil, but not the adults. You also have to be careful if you have any pets that like to chew on plants, and keep the plant in a contained area. This product works for three months. I have used this in the office as well, and it not only gets rid of fungus gnats but also aphids, spider mites, and anything else bug-wise that might be chewing on the plants. You do not want to use this on anything you will eat, such as citrus.

4) Mosquito Dunks/Bits - These work to kill both mosquito larvae and fungus gnat larvae. They are considered safe for pets, but they do not kill the adult gnats.

5) Insecticidal Soap - This contact spray will kill the adult gnats, but not the larvae.