Sciarid flies constitute the family of Sciaridae. The species that cause most damage to crops belong to the genera Bradysia and Lycoriella. Lycoriella species are mainly found in commercial mushroom cultivation where they can cause enormous damage.
Sciarid flies are usually found in damp, humid environments, and appear very commonly in greenhouses throughout the world. Although they generally do little harm to healthy plants, sciarid flies are particularly problematic in cuttings and other young growing plant material.