Darkwinged fungus gnat adults have eyes that meet above the base of the antennae. Eggs are hardly visible, oval, smooth, shiny white and semi-transparent. Pupae occur in silk-like cocoons in the soil. Life Cycle and Habits Fungus gnats reproduce in moist, shaded areas in decaying organic matter such as leaf litter. The life cycle is about four weeks, with continuous reproduction in homes or greenhouses where warm temperatures are maintained.
Broods overlap, with all life stages present during the breeding season.
Larvae not only feed on fungi and decaying organic matter, but on living plant tissue, particularly root hairs and small feeder roots. Brown scars may appear on the chewed roots. The underground parts of the stem may be injured and root hairs eaten off. Damage occurs most often in greenhouses or plant beds. Adults live about 7 to 10 days and deposit eggs on the moist soil surface or in soil cracks.