Rid of fungus gnats

Fungi are one of the most annoying houseplant pest problems. There are 8 ways to remove them.

Removal of mildew

The bane of my existence is the fungus gnat (Bradysia spp.). The larvae of this sneaky little creature prefer to live in very moist soil. Their larval feeding habits can damage plant roots, and stunt or kill seedlings, or even less established plants. Adults fly off the soil, often fluttering straight into your mouth or nose. Here are 8 ways to get rid of fungus gnats on your houseplants. I like to incorporate a few methods for better success.

1. Dry the plant

Fungus gnats are attracted to moist soil with mold and decaying organic matter. The best way to get rid of them is with less water.

2. Set up a sticky trap

The color yellow attracts fungus gnats, so place yellow sticky traps just above the soil surface. Adults fly into traps, become trapped, and die before breeding.

3. Use Bt product to control fungus gnats

Attack fungus gnat larvae with the bacteria Bt (Bacillus thuringiensis subsp. israelensis), which is available in several forms of bacteria applied to the soil and watered. Even if the plant is still very wet, go ahead and apply. Allow the plant to dry before treating again. Here are some products that have worked for me:

Mosquito Bitsand Mosquito Dunks

Sprinkle the granules into the soil or dissolve them in water before watering.

Knock-out mosquitoes

Dissolve the granules in water or sprinkle them on the soil, then water them.

Gnatrol

It is always under my control. Dilute the liquid with water.

4. Cover the soil

A ¼- to 1-inch-thick layer of sand or rice husks dries quickly after watering, providing a dry, hospitable place for adults to lay eggs.

5. Choose potting mix wisely

Fungus gnats always get into the fresh potting mix by infesting moist bags stored outside. Charcoal and coir-based potting mixes dry well and are less likely to encourage mosquitoes, while the bark and compost-based mixes are more susceptible.

6. Set up the potato trap

Cut the potato in half and place the cut side on top of the soil. Fungus gnats are drawn to feed on potatoes. Check daily and replace pieces infested with larvae.

7. Use insecticidal soap or neem oil

Although not as effective as PT, these natural insecticides kill fungus gnats when applied to the soil. Foliar sprays are not effective against fungus gnats.

8. Use natural predators

Nematodes (Steinernema) and predatory insects (Hypospis) feed on fungus gnats and their larvae and can be used in the potting mix as eggs that hatch and begin to feed. They gradually attack the problem until there is nothing left to feed the predators.