Flies often try to get inside a home through open doors or window cracks and they sometimes move into garages. Flies annoy people with their buzzing and flying around. They also have a strong negative association with filth and disease because of their preference for dirty locations. Garage owners can take some measures to prevent and get rid of flies in the garage.
Flies are attracted to decaying organic matter like rotting food, garbage, sewage and manure. Garages with garbage cans in them or near their entrances attract more flies than garages without garbage nearby. Additionally, a pet litter box or food dropped when entering or exiting the car will attract flies.
The problem with house flies, besides them being annoying, is that they can carry many diseases from all the gross things they land on throughout the day. They might transmit as many as 65 diseases to humans. Some illnesses that flies transmit through bacteria from fecal matter or other rotting things they land on include salmonella, diarrhea, dysentery, typhoid fever, E. coli and cholera. A fly problem in the garage not only looks unattractive; it poses a health risk.
Make it as difficult as possible for flies to enter the garage by keeping screens on windows, sealing cracks around windows and doors, and keeping the garage door closed as often as possible. Also take garbage outside and cover garbage cans in or near the garage. Do not let food sit around and change any pet litter boxes as often as possible. Eliminate sources of food or waste odors, which attract flies. Colorado State University Extension also suggests fixing any leaks in pipes because some flies breed in pipe seepage areas.
The University of California Davis recommends flypaper or inverted cone traps to reduce the number of flies in a confined indoor area. However, inverted cone fly traps have an unpleasant smell, so homeowners might choose to keep them outside of the garage but near it. In most cases, sanitation improvements in combination with fly traps or fly-swatting should get rid of flies in the garage. The University of California Davis only recommends an insecticide if sanitation efforts and window screens fail. In this situation, a nonresidual pyrethrin aerosol can work to get rid of fly problems. Good old-fashioned fly-swatting also helps for small numbers of flies.