Fungus Gnat Larva / Fungus Gnat Maggot
Scientific Name: Sciaridae or Mycetophilidae (Family)
Order & Family: Diptera (Order); Sciaridae (Dark-winged fungus gnats) or Mycetophilidae (Fungus gnats)
Size: 3–6 mm (approx. 1/8 to 1/4 inch) in length when mature.
Natural Habitat
Typically found in damp soil, overwatered houseplants, greenhouses, and areas with high humidity and decaying organic matter.
Diet & Feeding
Primarily feeds on fungi, decaying plant matter, algae, and compost. Occasionally, they will feed on the root hairs of live plants if organic matter is scarce.
Behavior Patterns
The transparent/whitish larvae live in the top few inches of moist soil. They often leave slime trails (similar to tiny snails) if they emerge onto surfaces. They develop into small, dark, flying adults that are often mistaken for fruit flies.
Risks & Benefits
Risks: Can be a major pest for houseplants and greenhouse crops by damaging root systems (especially seedlings) and spreading fungal diseases like Pythium. Benefits: In wild ecosystems, they aid in decomposition and nutrient cycling.
Identified on: 2/16/2026