Fungus gnats do not harm humans but can be very annoying when they fly around our house plants. They are very tiny and only about the size of a fruit fly.

Fungus Gnats are attracted to the moisture and organic matter in potting mixes. Adults lay up to 200 eggs just below the soils surface which after 3 days hatch into larvae. The larvae feed on breaking down organic matter in the soil or decaying roots. Large populations can become a problem if they start feeding on fresh young roots.

Prevention

Soil that is too wet is a perfect breeding ground for fungus gnats.

Keep your indoor plants (other than ferns) on the dry side and water sparingly. Check the moisture of the soil by sticking your finger into the soil, if you finger comes out clean then it means it is ready to water. Also, if you are able, gently lift the pot to check its weight. If the pot is light, you can water, if its heavy then leave it for longer.

Water moisture meters are a great tool to help with correct watering.

Treatment

Place a 3cm layer of Yates Gnat Barrier on top of the soil. Gnat Barrier is made from natural abrasive pumice granules, which provide an effective physical barrier against fungus gnats.

Spray GroSure Houseplant Insect Control Spray around both soil and plants to control Gnat infestations.

Spray around the soil of the affected plant’s with DEEM spray. This product is organic with a blend of Debug and small amounts of neem oil. Note that this product will leave a white residue on the soils surface.

Easy Trap yellow sticky traps are great, Gnats are attracted to the yellow traps and when they land on them they get stuck on the glue on the trap.