Fungus Gnat
Scientific Name: Examples include Bradysia spp. (Sciaridae) or Mycetophila spp. (Mycetophilidae)
Order & Family: Order: Diptera, Family: Sciaridae (dark-winged fungus gnats) or Mycetophilidae (fungus gnats)
Size: Adults typically measure 2-8 mm (0.08-0.31 inches) in length, with the black spots on the lint roller appearing to be around 1-2mm.
Natural Habitat
Fungus gnats thrive in moist environments rich in organic matter. Common habitats include damp soil of potted plants, greenhouses, leaky plumbing areas, and any place with excess moisture and decaying organic material.
Diet & Feeding
Larvae primarily feed on fungi and decaying organic matter in soil. They can also feed on plant roots, especially tender new roots, which can damage seedlings or young plants. Adult fungus gnats do not feed.
Behavior Patterns
Fungus gnats are typically attracted to moist environments where fungi and decaying organic matter are present. Adults are weak fliers and often seen near potted plants, windows, or sinks. Larvae live in the soil and feed on fungi or decaying plant material. Their lifespan is short, with adults living for about a week, but they can reproduce rapidly, leading to infestations if conditions are favorable.
Risks & Benefits
Potential risks include nuisance infestations indoors. While adults are harmless, their presence can be annoying. Larvae can damage plants by feeding on roots, particularly seedlings, young plants, or plants already stressed, leading to wilting, stunted growth, or even death in severe cases. They do not pose direct health risks to humans. On the benefit side, as decomposers, larvae contribute to nutrient cycling by breaking down organic matter.
Identified on: 8/29/2025