Fungus Gnat

Natural Habitat

Damp, organic-rich environments, often associated with potting soil, decaying plant matter, and high humidity indoors. Larvae live in soil.

Diet & Feeding

Adult fungus gnats typically do not feed or feed on liquids. Larvae primarily feed on fungi, decaying plant material, and sometimes plant roots (especially young or unhealthy roots).

Behavior Patterns

Adults are weak fliers and often seen flying erratically near potted plants or windows, or crawling on surfaces. Larvae are subterranean, feeding in the soil. Their life cycle is relatively short, typically lasting 3-4 weeks from egg to adult depending on temperature and humidity, leading to rapid population growth under favorable conditions. They are often most active during dawn and dusk.

Risks & Benefits

Potential risks include being a nuisance pest indoors. While adult fungus gnats are harmless to humans, their larvae can damage the roots of plants, particularly seedlings and young plants, leading to wilting, stunted growth, or even death in severe infestations. They do not bite or transmit diseases to humans. Some species may play a minor role in decomposition of organic matter, but are generally considered pests in horticultural settings.

Identified on: 10/5/2025