Large flies indoors—typically blow flies or cluster flies—either hatch from eggs laid on a decaying food source (like a dead pest in your walls) or emerge from attics and wall voids where they previously hid to survive cold weather.
If huge, slow-moving flies are suddenly appearing in your home, you are likely dealing with cluster flies or blow flies. They generally aren't breeding indoors; they are either hatching from a hidden dead rodent/garbage source or emerging from wall voids and attics where they have been overwintering.
Bottom Line: Crane Flies Are Harmless to Humans
Crane flies might look big and scary and can destroy your lawn, but they are medically harmless to people. With good lawn care, you can get rid of most crane flies.
To quickly get rid of big flies in your house, eliminate their food and breeding sources, and then use targeted traps or sprays. Seal your home against new entries and, for an immediate cleanup, simply vacuum them off windows where they tend to gather.
Here are the 5 most effective natural remedies to get rid of flies:
To get rid of flies permanently, you must eliminate both their indoor breeding grounds and outdoor attractants. Focus on sealing entry points, removing all accessible food and waste, and setting up targeted traps.
To find where flies are coming from, you must first identify the type of fly, as different species breed in different environments. Trace them by their food source: Fruit/Drain flies breed indoors on organic decay, while House flies/Blow flies usually find their way in from larger outdoor breeding grounds.
Lavender, eucalyptus, peppermint and lemongrass essential oils – Not only will spraying these oils around the house create a beautiful aroma, but they will also deter those pesky flies too. Apple cider vinegar – Flies love the smell of apples and vinegar.
Big, black flies fall into a few different categories depending on their appearance and behavior:
Fly season in the U.S. typically peaks from late spring through early fall, with activity highest during warm, humid months. House fly and fruit fly season intensifies when food waste, overripe produce, and moisture are abundant.
To kill adult crane flies instantly, use a fast-acting pyrethrin-based aerosol spray (like Country Vet CV-80D or Prozap Dy-Fly) or a pyrethroid-based contact insecticide (such as Sevin or Talstar P). You can also use a vacuum cleaner for an instant, chemical-free option inside your home.
Here's our list of the top 15 scariest and creepiest insects from around the world.
Flies don't hear human voices the way we do, but their antennae can detect the sound waves. Rather than using traditional ears, many flies use tiny, feathery hairs on their antennae to sense vibrations caused by airborne sounds. While they physically perceive the noise, they don't understand what you are saying.
As temperatures drop in the fall, adult flies search for warm spaces to overwinter. Homes, especially those with high elevation or lots of sun exposure, often attract them.
Yes, flies can get hurt when you hit them, though exactly how much they are affected depends on the force and the surface you hit them against.
The Bible does not contain specific rules about dealing with modern houseflies. However, flies are mentioned in a few notable symbolic and historical contexts in scripture:
Large flies inside your home are usually blow flies or cluster flies. Getting rid of them requires a two-step approach: eliminating their breeding source (like decaying organic matter or animal waste) and setting up traps or chemical barriers around common congregation points like windows.
House flies can lay their eggs in several locations inside a house, especially where there is access to organic material that provides a suitable environment for their larvae to thrive. Here are some common places where flies might lay eggs indoors: Trashcans. Compost piles.
Black flies (buffalo gnats) are notorious outdoor pests. While harmless in terms of disease transmission in North America, female black flies inflict painful, itchy bites that leave tiny, bleeding puncture wounds when they scrape the skin to draw blood.
To kill flies immediately, use an aerosol flying insect spray containing pyrethrins, which delivers a quick knockdown. For a direct hit on resting flies, use a solution of dish soap and water in a spray bottle.
Yes, anecdotal evidence suggests Vicks VapoRub can help deter black flies in the immediate area where it is applied. Its active ingredients—menthol, camphor, and eucalyptus—produce strong scents that confuse and repel many insects. However, its effectiveness is highly localized, temporary, and less reliable than standard commercial repellents.
The folk remedy of hanging a bag of water with pennies inside is based on light refraction and the unique structure of a housefly's eyes. While widely used in outdoor dining areas and porches, scientific evidence supporting its effectiveness is limited.
Vinegar and Dish Soap - Fill a bowl slightly with apple cider vinegar, wine or honey with some dish soap (washing up liquid). Cover the bowl with plastic wrap with punctured holes or leave uncovered. Flies will be attracted to the smell and will get stuck within the liquid.
A fly infestation can last anywhere from 7 to 10 days (for a brief, single-hatch cycle) to several months. Because adult flies reproduce rapidly, laying hundreds of eggs in warm, organic matter, the infestation will persist indefinitely as long as their food and breeding sources remain accessible.
Drain flies lay their eggs in the gelatinous slime (biofilm) and decaying organic matter that accumulates inside plumbing pipes and moist areas. Females can lay 30 to 100 eggs at a time, which hatch in just 32 to 48 hours.