How to Get Rid of Fungus Gnats?

Fungus gnats are a pest that resemble small fruit flies and lay their eggs in the soil of houseplants. Here are some means of controlling them in your plants.

Fungus Gnats and How to Get Rid of Them

Fungus gnats are tiny flying insects that look like fruit flies and are a common houseplant pest. They lay their eggs in moist potting mix, where the larvae hatch, feed, and eventually grow into adult gnats, continuing the cycle. Although fungus gnats are more annoying to people than harmful to plants, a large infestation can become problematic.

Step 1: Control the Adults
Use Wine or Vinegar Traps: Place a small glass of red wine or white vinegar near your plants. The scent attracts fungus gnats, and the alcohol or acid kills them.

Yellow Sticky Traps: Place yellow sticky traps near your plants. Fungus gnats are drawn to the yellow color, and these traps will help reduce their numbers. Replace traps as they fill up.

Step 2: Reduce Soil Moisture
Fungus gnats lay eggs in moist soil, so let the top inch of soil dry out between waterings. Many tropical plants benefit from allowing the soil to dry halfway down the pot, which also discourages gnats.

Use a Sand Barrier: Spread a 1-inch layer of sand over the soil. This creates a dry, non-organic surface where gnats can’t lay eggs.

Diatomaceous Earth (DE): Sprinkle a layer of DE over dry soil. DE is a powder made from fossilized algae that kills insects on contact but is safe for plants, people, and pets. Let the DE sit on the soil until you water again, as it becomes ineffective when wet. Reapply as needed.

Additional Natural Controls
Beneficial Nematodes: These microscopic organisms, when mixed with water and added to the soil, seek out and kill fungus gnat larvae. Nematodes are safe for plants, pets, and people and are available at garden centers.

Bacillus thuringiensis israelensis (BTI): This bacterium, available in products like Mosquito Bits, can be mixed with water and used to water your plants. It kills fungus gnat larvae without harming plants or other beneficial insects.

By following these steps, you can manage fungus gnat populations and protect your plants from further infestations.