Whacking flies with a fly swatter – or trying to – is one of the most common forms of "controlling" house flies, and if you have only one or two, it may even be the most effective. But to reduce or eliminate an infestation, you have to find and eliminate the things that are attracting the flies and enabling them to feed and breed.
This involves inspection, sanitation, exclusion, and mechanical and chemical control, as warranted.
- locate the areas and materials that are attracting the flies,
- identify the flies that are present.
The following describes indoor control methods for house flies. If the inspection found it to be a cluster fly or other large fly, or fruit or other small flies, specific control methods will be somewhat different – although sanitation and exclusion are key to controlling virtually any pest.
- Eliminate fly breeding sites the material that attracted them and on which they are feeding or laying eggs
- Keep trash closed in lidded containers and take out often.
- Clean spills quickly and cover any non-refrigerated foods.
- Keep pet feeding and litter areas clean.
- Fix drips and eliminate any areas of excess moisture.
- Keep window and door screens in good repair.
- Keep doors, windows and vents closed as much as possible
- Caulk or cover other possible fly entry areas, such as around vents. Screen vent openings.
- Plug weep holes with pieces of nylon or plastic scouring pads or square pieces of window screening that are 4 to 5 inches wide
- When warranted, use automatic door closing devices.
Seal all cracks and holes in the house siding and around windows or doors.
- Adult house flies, cluster flies and other species often overwinter in wall voids and attics then enter homes from the attic or wall voids at different times during the winter. Prevent this with the same exclusion methods.
- Fly swatters can kill small numbers of flies, but be careful to not swat flies near food preparation areas, because this can contaminate food with flying body parts.
- Some traps can help control flies, such as sticky fly papers or ribbons that include an odor attracted.
- House flies are also attracted to white surfaces, thus the reason many sticky traps come in white.
- These should be used in food preparation areas or where infants, elderly or insecticide-sensitive people sleep.
- Flies traps can be baited with molasses, sugar, fruit or meat. Pre-baited traps often use fly pheromones (sex attractants)
Ultraviolet light traps can be useful, but must be properly placed. Place:
- where it cannot be seen from outside, so it doesn't attract flies indoors.
- no more than 5 feet above the floor – where most flies fly.
- away from competing light sources and food preparation areas.
- where they are not competing with daytime sunlight.
Chemical control is one component of an integrated fly management program. It is recommended that all other methods be attempted first, because flies have become resistant to many insecticides making fly populations difficult to control with such chemicals. When needed:
- Pesticide-releasing fly strips can be placed in attics and small, unoccupied rooms, such as closets and storage rooms.
- Spraying non-residual, contact aerosols that are labeled for flies can provide temporary relief by killing the adult flies. However it does not get to the source, so will not provide long-term control.
- Residual insecticides, labeled for flies, can be sprayed around door and window casings, onto screens, under eaves or around any other fly entry points.
- When using any pesticide, be sure to read the product label and follow all directions.