Fungus Gnats

Behavior and Habitat

Fungus gnats are very small and can be an extreme nuisance. They are attracted to sunlight and also people's colognes or perfumes. Fungus gnats prefer to lay their eggs in moist potting soil, which is why buildings containing potted plants or atriums may often have problems. Soon after the eggs are laid, the larvae emerge to feed on fungus growing in the damp potting soil. After feeding for a short period, the larvae pupate. A few days after pupating, the adult fungus gnats emerge to start the process again. Fungus gnats may breed anywhere that suitable molds or fungi might grow. A fungus gnat infestation in a home could mean a moisture problem is present. Although fungus grows in areas such as moist wood (the result of leaks or poor insulation) and poorly ventilated crawlspaces and attics, most infestations are associated with moist potting soil. Look for adult fungus gnats in areas where moisture problems have been observed or are suspected. Fungus gnat eggs and larvae are usually not on the exposed surface of soil and are too small to see without proper magnification.