The genus Phlebotomus contains some species which are blood feeders and they are vectors of several important diseases including Leishmaniasis, but the members of the genus Psychoda do not bite and restrict their larval diet to decaying organic materials they find in damp situations, including on soils or leaf litter. In structures this may be a sludge buildup in floor or sink drains, giving the flies one of their common names. They may also occur in large numbers in septic systems, sewage treatment plants, or dirty garbage containers. The eggs are laid in masses of from 30 to 100 eggs on the surface of the material in which the larvae will feed. The larvae feed within the sludge, breathing through siphon tubes on their body that project out of the material. The time from egg to adult fly may be from 8 to 24 days, depending on the temperature. Adult flies are attracted to lights.
Elimination of larval breeding sources is critical, by removing sludge buildup in floor or sink drains and controlling moisture accumulation in low spots on floors or exterior areas. Regular washing of dumpsters will remove spilled materials.