Fungus Gnat Control
Adult fungus gnats don't do damage to plants, and are more of a nuisance than anything else. However, the larval stage can damage roots and stunt growth, particularly in seedlings and young plants. Fungus gnat larvae most commonly affect indoor plants. A wilting houseplant may not indicate a lack of water, but rather root damage by fungus gnat larvae. Fungus gnat larvae feed on fungi, decaying organic material, and live plant tissue. They thrive in wet, over-watered conditions.
So what works best for Fungus Gnat control?...
Most of the fungus gnat’s life is spent as a larva and pupa in organic matter or soil, so the most effective control methods target these immature stages rather than attempting to directly control the mobile, short-lived adults.
Nematodes such as Stenernema feltiae and Stratiolaelaps scrimitis are both excellent soil-dwelling predators that attack the fungus gnat larvae. Stratiolaelaps scrimitis are typically used for preventative measures, Larger infestations may require multiple releases.
In the event of a large fungus gnat infestation, Stenernema feltiae and Stratiolaelaps scrimitis may be paired with Dalotia coriaria (another effective soil dwelling predator).
Stenernema feltiae: Fungus gnat larvae, Root Aphids, Leaf Miners, Shore Flies, and Thrips.
Stratiolaelaps scrimitis: Fungus Gnat Larvae, Thrips, Sciarid Flies, Shore Flies, Root Aphids, Springtails, Root Mealybugs and Poultry Mites.
Dalotia coriaria: Fungus Gnats, Shore Fly, Thrips, Springtails, and Root Aphids.