Fungus Gnat
Scientific Name: Bradysia spp. (for Sciaridae, common houseplant fungus gnats) or various genera within Mycetophilidae
Order & Family: Order: Diptera, Family: Sciaridae or Mycetophilidae
Size: Adults typically 2-4 mm (0.08-0.16 inches) in length. Larvae can grow up to 6 mm (0.24 inches).
Natural Habitat
Commonly found in damp, humid environments, especially around houseplants, greenhouses, and areas with decaying organic matter (e.g., compost piles).
Diet & Feeding
Adults do not feed. Larvae feed on fungi, decaying organic matter, and sometimes the roots of plants.
Behavior Patterns
Fungus gnats are attracted to moist environments and decaying organic matter. Adults are weak fliers and typically found near the soil surface of potted plants. Larvae feed on fungi and decaying plant material in the soil, and sometimes on plant roots. They have a short life cycle, from egg to adult in about 3-4 weeks depending on conditions.
Risks & Benefits
Risks: Primarily a nuisance pest in homes. Large infestations can damage the roots of seedlings and young plants, leading to wilting or stunted growth, especially in nurseries and greenhouses. They do not bite humans or transmit diseases. Benefits: In natural environments, they contribute to the decomposition of organic matter.
Identified on: 8/26/2025