They are found hovering around overripe fruit or fermenting material such as beer or soft drinks. Breeding sites contain decomposing material that contains yeast and other microorganisms associated with fermentation. Overly ripe fruit and vegetables, fermenting liquids in recycling bottles and cans, unused garbage disposals, caked organic matter in trash containers, soured mops, organic seepage under sinks and drains, and slimy drain pans in coolers and refrigerators are all breeding sources. Generation times can be 10-14 days. Adult vinegar flies can be killed with pyrethrin sprays, but the source must be found and eliminated for control.
Adults are small, hairy, dark, weak flying gnats that often congregate in sinks and bathrooms.
They rest with wings flat on the back and have a triangular or delta shape. Adults are often found some distance from the source. Hot water, drain cleaners or other flushing materials that eliminate the slime should solve the problem. They breed on dead, decaying animals, animal waste, and high protein garbage. Check chimneys, attics, vents, crawl spaces and accessible wall voids for food sources.