There’s arguably nothing more irritating than the constant buzzing of a fly inside your peaceful home. Beyond the annoyance, flies can carry and transmit harmful pathogens, leading to serious illnesses like food poisoning, cholera, and dysentery. Simply put, flies are unwelcome guests in any home.
Fortunately, while there are over 110,000 species of flies globally, only a small fraction are common household pests. “The flies we frequently encounter are often referred to as filth flies. Their natural role is to break down organic matter,” explains Faith M. Oi, Ph.D., an extension associate professor specializing in urban entomology at the University of Florida. “By being mindful of our habits, we can significantly reduce the likelihood of these pests and the diseases they carry.”
The primary goal is to prevent flies from entering our homes in the first place. Elmer Gray, an entomologist and researcher at the University of Georgia, notes, “There isn’t one single solution for fly control. However, implementing a few basic preventative measures can greatly limit their access to our living spaces.”
Continue reading to discover effective strategies for keeping flies away, including the most reliable natural methods to maintain a fly-free home.
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Identifying Common Flies Found Indoors
While any fly species might wander inside, fruit flies and bottle flies are common, but house flies are the most frequent indoor culprits. Identifying the type of fly can be helpful and is usually determined by size and location within your home.
House Flies
House flies are typically around 1/4 inch in length and recognizable by the four dark stripes on their backs. They commonly lay eggs in decaying organic materials like garbage, compost, and even the residue inside recycling bins.
Under optimal warm conditions, house flies can reproduce rapidly, completing their life cycle in less than a week, according to Dr. Oi. Warmer temperatures accelerate their development from egg to adult. For instance, if you neglect to take out the kitchen trash before a week-long vacation, you might return to a less-than-pleasant surprise of fly larvae in your kitchen.
Blow Flies and Bottle Flies
Blow flies and bottle flies are other types that frequently find their way indoors. Similar in size to house flies, they are distinguished by their metallic sheen, exhibiting green, blue, or bronze colors on their robust bodies. These flies are attracted to and breed in animal waste and carcasses. An influx of blow flies or bottle flies indoors may indicate the presence of a dead animal, such as a rodent or bird, possibly in hidden areas like an attic or chimney, suggests Gray.
Filth Flies (Drain Flies)
Small filth flies, often called drain flies, thrive in the slime and decaying matter that accumulates within drain pipes, explains Dr. Oi. Resembling tiny moths, drain flies are about 1/16 inch long with hairy bodies ranging from yellow to brownish-black, and they characteristically hold their wings over their bodies when at rest. These flies are commonly found in kitchens and bathrooms, near drains and garbage disposals.
Fruit Flies
Tiny fruit flies are often brought inside from outdoors, drawn to ripening fruits and vegetables on kitchen counters, or they may arrive on already infested produce. About 1/8 inch in length with distinctive red eyes, fruit flies lay their eggs on the surface of fermenting produce, as well as in trash cans, drains, and recycling bins.
Are Flies Really Harmful?
While common house flies do not bite, some species, like horse flies and black flies, are known to bite and can inflict painful wounds. More significantly, flies are vectors for numerous pathogens that cause diseases such as dysentery, typhoid fever, tuberculosis, food poisoning, and cholera. Due to these health risks, it’s crucial to discard any food that has come into contact with flies.
Practical Strategies: How to Keep Flies Away
Flies have a relatively long lifespan, living up to 30 days, and are prolific breeders, laying numerous eggs during their lifetime. Depending on the specific type of fly causing issues, control methods may vary. However, these general tips are effective for overall fly prevention:
1. Maintain and Repair Window Screens
Ensure your window screens are in good condition. “Window screens are your primary defense against flies,” Gray emphasizes. Screens with holes, tears, or gaps provide easy entry points for flies and other unwanted pests. Regularly inspect and repair any damage to your window screens to maintain a barrier against flies.
2. Manage Trash Properly
Promptly dispose of rotting fruits and vegetables and avoid leaving food waste, like banana peels, exposed on countertops, advises Dr. Oi. Take out indoor trash bags at least once a week to prevent the buildup of rotting food that attracts flies into your home. More frequent removal might be necessary depending on waste accumulation.
For outdoor trash management, Gray recommends securely tying trash bags and sealing them tightly inside garbage cans to contain odors. Position garbage cans as far away from house entrances as possible. Similarly, compost bins should be located away from the house to minimize fly attraction, suggests Dr. Oi. Regularly cleaning up pet waste daily is also crucial, as it can be a significant attractant for flies, according to Gray.
3. Regularly Clean Garbage Containers
In addition to keeping trash and recycling bins away from your house, regular cleaning is essential. Flies are attracted to fermentation, such as residues in alcoholic beverage cans. Rinsing cans and food containers before placing them in recycling or trash bins can significantly reduce fly attractants, notes Dr. Oi. Periodically wash out your garbage and recycling bins with soap and water to eliminate lingering odors and residues that attract flies.
4. Protect Food During Outdoor Activities
When eating or cooking outdoors, it’s important to protect food from flies. Cover picnic foods and outdoor meals with fine mesh food covers, suggests Gray. Flies can transfer pathogens through contact, and they also defecate and regurgitate while on food surfaces, making unprotected food unhygienic and unappetizing.
Using a box fan when sitting or dining outdoors can also deter flies. Flies dislike strong air currents. “Air movement strong enough to create a ‘bad hair day’ for you is generally sufficient to keep them away,” quips Dr. Oi.
5. Keep Drains Clean and Clear
Flies are attracted to the organic buildup in drains. Regularly clean your drains, and if you notice buildup, use a long-handled brush to scrub the drain thoroughly. Pouring boiling water down drains periodically can also help flush away organic matter and prevent drain fly infestations.
Recognizing Signs of a Fly Problem
If you are noticing an increase in flies and are unsure of the source or extent of the problem, there are indicators to look for. An increase in indoor flies, swarms of flies outside, fly droppings (small dark spots), or the presence of maggots can signal an infestation requiring professional pest control.
To check for drain flies specifically, Dr. Oi suggests a simple test: take a clear container, smear petroleum jelly inside, and place it upside down over the drain overnight. Drain flies attempting to emerge will get stuck in the petroleum jelly. If drain flies are present, use a stiff drain brush and a drain cleaner specifically designed to break down organic sludge.
Debunking Fly Repellent Myths
Despite popular beliefs, many DIY fly “repellents” are ineffective. This includes pungent soap bars, essential oils, sonic repellent devices, and the internet myth of hanging bags of water with pennies. “None of these methods are scientifically proven to repel flies,” states Gray.
Furthermore, relying on insecticides to kill flies is not a sustainable solution. “Flies are becoming increasingly resistant to many pesticides available for general use,” explains Dr. Oi. “Also, pesticides are not a permanent fix. If you have a significant fly problem, you must identify and eliminate the breeding source. Flies are breeding somewhere.” For major infestations, contacting a professional pest control service is often necessary.
Effective Methods to Get Rid of Flies
The most effective long-term strategy for managing flies, both indoors and outdoors, is to eliminate their food sources and breeding grounds. While flies are known to dislike citronella and other strong scents like lavender, rosemary, catnip, and basil, planting these outdoors might offer minimal deterrence. White outdoor lights can attract flies, so switching to yellow-colored bulbs can be helpful. Eliminating stagnant water and moisture sources is also crucial to prevent breeding.
For flies that do make it indoors, both Dr. Oi and Gray recommend the use of a fly swatter as a highly effective method. “It’s an effective, pesticide-free way to kill individual flies,” says Gray. Dr. Oi also advises keeping sanitizing wipes handy to clean the fly swatter and the surface where a fly was swatted to maintain hygiene.
To reduce indoor flies proactively, consider hanging sticky traps in garages or near doorways that lead into your home. While not aesthetically pleasing, sticky traps can help reduce the number of flies attempting to enter your living spaces when doors are opened, suggests Gray.
