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 really get rid of flies, you have to get rid of the things that are attracting the flies and providing food and breeding sites.
This means inspection, sanitation, exclusion, and mechanical and/or chemical control.
1. House Fly Inspection
Before you can do anything about keeping flies out of the house you have to know where they are and why they are there. So you need to inspect to find the areas and materials that are attracting the flies and to identify the flies that are present.
This article discusses control methods for house flies. If your inspection shows that you have a problem with cluster flies or other large flies, or fruit flies or other small flies, the control methods will be somewhat different. (Click the links in this paragraph to read more about those flies.)
2. Sanitation Reduces Flies
House flies are called filth flies because they are attracted to filth. So keeping things clean is the first step in reducing flies is cleaning the areas where they are feeding and breeding:
- 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.
Exclusion means eliminating the ways that flies can get into the home, thereby "excluding" them from entry. These include:
- Keep window and door screens in good repair.
- Keep doors, windows and vents closed when not in use. Use automatic door closing devices where possible.
- Caulk or cover other possible fly entry areas, such as around vents, cracks and holes in the house siding, and windows or doors. Screen vent openings.
- Plug weep holes with pieces of nylon, plastic scouring pads or window screening.
4. Mechanical Control
Mechanical Control involves anything that is not chemical in nature but kills or captures the flies. Some of these are:
- Fly swatters can kill small numbers of flies, but be careful to not swat flies near food areas, so flying body parts don't get in the food.
- Trap flies with sticky fly papers or ribbons that include an odor attractant. (Many are white because house flies are attracted to white surfaces.)
- You can bait flies traps 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:
- 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 (including sunlight) and food preparation areas;
5. Chemical Control
Although many people think of chemical control first for any pest control, it is really just one part of an integrated fly management program.
It is recommended that all other methods be tried first because flies have become resistant to many insecticides making them even more difficult to control. So, only when and where needed:
- Place pesticide-releasing fly strips in attics and small, unoccupied rooms, such as closets and storage rooms.
- Use non-residual, contact aerosols that are labeled for flies to kill adults. Because this does not get rid of the source, it will provide only temporary relief.
- Spray a residual insecticide, labeled for flies, around door and window casings, onto screens, under eaves or around other fly entry points.
- When using any pesticide, always read the product label and follow all directions.