Fungus Gnats

Fungus gnats are small dark flies commonly seen walking or flying around the soil surface.

The adults are mostly a nuisance, but their presence can indicate that the soil is remaining consistently wet.

Their larvae live in the growing medium.

Signs of Fungus Gnats

Look for small black flies around the pot, flies emerging when the soil is disturbed, or persistently wet soil.

What to Do

First examine your watering routine.

Allowing the soil surface to become appropriately less wet between waterings can make conditions less favourable for fungus gnats — but never deliberately allow a bonsai to dry out excessively just to control them.

Persistent infestations may require a treatment specifically intended for fungus gnat larvae.