sciarid

Sciarid is a common name for members of the family Sciaridae, a group of small, slender flies in the order Diptera. The most familiar sciarids in horticulture belong to the genus Bradysia and are commonly called dark-winged fungus gnats. Adults are typically 2–4 mm long, with dark bodies, translucent wings, and long legs and antennae.

Larvae are pale, legless maggots with a dark head capsule. They feed primarily on fungi and decaying organic matter, and some species can feed on delicate plant roots or root hairs. The life cycle begins when female flies lay eggs in moist potting mixes, compost, or other rich organic substrates. Larval development usually takes two to three weeks, depending on temperature and moisture, followed by pupation in the soil. Adults emerge, mate, and die within a short period, often less than a week.

Sciarids thrive in damp, shaded environments such as potted plants, greenhouses, and freshly prepared organic media. They are not major vectors of plant pathogens, but larval feeding can stunt seedlings or reduce growth, especially in young transplants.

Management focuses on reducing breeding sites and preventing overwatering: improve drainage, allow the soil to dry between waterings, remove decaying material, and quarantine new plants. Monitoring tools include yellow sticky traps. Biological controls such as Steinernema feltiae nematodes and Bacillus thuringiensis israelensis (Bti) can reduce larval populations. Chemical controls are typically limited in effectiveness and should follow local guidelines.

Sciarids occur worldwide, with higher populations in moist indoor environments and greenhouses.