Make an easy and inconspicuous DIY fly trap from an empty plastic soda bottle to stop houseflies from buzzing inside your home. Baited with a liquid that attracts flies, like sweetened water or another attractive substance, a DIY fly trap set in a hidden area will quickly lure ordinary houseflies.
Flies smell the bait and fly into the bottle to get to it (either to lay eggs or to feed). Once inside, they are easily caught as they fly down the neck of the trap. Flies will become trapped because they can't navigate back up the narrow opening, or they will be unable to fly if their wings get wet. This trap can be used indoors or outdoors.
Some of the tried-and-true methods of controlling houseflies indoors have drawbacks: flyswatters are messy, and pesticides can be harmful, potentially releasing dangerous chemicals into the air. Instead, here are the steps to make a natural bait trap that's bound to stop flies in their tracks.
Homemade Fly Trap Bait Options
- Fruit-flavored dish soap
- Sugary water
- Old fruit
- Apple cider vinegar
- Old wine
- Rotting meats (outdoor trap)
Equipment / Tools
- Serrated knife
- Permanent marker
- Cutting board
- Hole punch (optional)
- Two-liter soda bottle
- Bait, such as ripe fruit
- Vinegar (optional)
- Piece of wire to hang your trap (optional)
Mark a Cutting Line
Draw a line all the way around the bottle using a permanent marker, just below the tapered neck.
Cut the Top off the Bottle
Use a sharp knife with a serrated blade to cut along the line, severing the top of the bottle. Cut on a cutting board so there's no damage to your counter or table surface.
Assemble the Fly Trap
Remove the soda cap, then flip the top of the bottle upside down and slide it into the bottom of the bottle, like a funnel, to complete the fly trap.
Bait the Trap
Remove the "funnel" from the bottle so you can place the bait. Choose a bait for your trap.
Flies are attracted to nearly any decaying organic material. Though it is meat and feces that flies seek out to lay eggs (the larvae, which we know as maggots, will immediately feed on those materials when they hatch from fly eggs), few people will want to use that as indoor bait. Consider these pleasant ideas for bait:
- Slightly over-ripe fruit
- A 50/50 water and sugar mix
- Water mixed with honey or maple syrup for a stickier solution
- Fruit-scented dish soap
If you are using this trap outdoors, use a more pungent bait. To keep bees out of your indoor or outdoor trap, add a splash of vinegar to the mix.
Make a Handle for the Fly Trap
If you prefer a hanging trap, use a hole punch to punch two holes on opposite sides at the top of the bottle. Make sure they go through both layers of the trap. Then thread a piece of wire through the holes, crimp the ends, and your trap is ready to hang.
Tips to Make the DIY Fly Trap Work
There are certain times of year when flies are more prevalent. In colder climates, this is often in the spring as the sun begins to warm the walls of the home, bringing out the first flies from their winter stupor. Houseflies have a predictable lifecycle that can include many hatch cycles each season, so if you set out your trap when the first flying pests appear, you stand a good chance at minimizing fly outbreaks, since you'll be trapping most of them before they have a chance to lay eggs that fuel the next cycle.
In some environments, trapping may be an almost constant affair. In warm climates near animal pens or pastures, for example, flies may be an almost constant presence, and you'll want to keep the DIY fly traps in place for most of the warmer months.
To maintain the trap, empty the dead flies and re-bait your trap regularly. If you decide to use meat or animal droppings (chicken litter, rabbit pellets) as bait, you'll also need to destroy any larvae that you find in your trap. Rinsing the bottle out with hot water should do the trick, or just create a fresh new trap.
Which bait works best for a homemade fly trap?
If outside your house and not within nose-shot of you, make a bait that combines sweet and meat. House flies can't resist rotting meat, and fruit flies are attracted to the sweet stuff. For example, mix scraps of rotting meat like fish (the older, the better) with sugar or honey. For indoor traps, stick with old fruit or honey. To discourage bees from getting lured to your trap, add a splash of apple cider vinegar.
Why do some people add liquid dish soap to the trap mixture?
In most cases, inverting the bottle top makes it too difficult for the fly to find an exit. But, you could also add a few drops of liquid dish soap to the mix. The sugar and vinegar smell attracts the flies, while soap changes the surface tension of the liquid, drowning the flies.
Why does my house have so many flies?
Warmer weather brings flies out of dormancy, but also, people tend to go outside more and keep the door open longer. Flies also breed quickly, laying over 150 eggs at a time. So, if given the opportunity and your home has moist, warm spots or some decomposing trash in the garbage can—these are ideal situations for a breeding fly to lay eggs.
Nicolopoulou-Stamati P, Maipas S, Kotampasi C, Stamatis P, Hens L. Chemical pesticides and human health: the urgent need for a new concept in agriculture. Front Public Health. 2016;4. doi:10.3389/fpubh.2016.00148
Merchant, Michael. Indoor Flies and Their Control - What Causes Indoor Flies?. Texas A&M Agrilife Extension Service.
Featured Creatures: Common Name: House Fly. University of Florida Institute of Food and Agriculture Services.