While fruit flies don’t cause the itch that mosquitoes do, and they may not be as annoying as houseflies, when you’ve got them in your home and buzzing in your face, there’ll be no convincing you that they aren’t the personal emissaries of Satan.
But you don’t have to lose apples and bananas to your unwanted house guests much longer. With the help of two experts—an entomologist and a veteran restaurant director of operations—we’ll explain what exactly fruit flies are, how to prevent them, and how to get rid of them once they’ve invaded.
“They’re always here,” says Molly Keck, an entomologist with the Texas A&M AgriLife Extension Service and a specialist in the Texas Integrated Pest Management program. “It’s not your fault that you got them in the first place, but it is your fault if you keep them around.”
What Is a Fruit Fly?
The flying insects making up the current plague in your home may not technically be fruit flies—the name most commonly applied to Drosophila melanogaster, a typically red-eyed pest that grows to about three millimeters long as an adult (about the width of a grain of rice). “It’s a common name people attribute to many small flies,” says Keck. ”There’s red-eyed fruit flies, black-eyed fruit flies, fungus gnats, drain flies—a lot of small flies you might find.” As their names indicate, things like fungus gnats and drain flies may look like fruit flies, but they are technically different beasts with their own preferred breeding and feeding grounds.
The good news is that, generally speaking, the methods for preventing and treating all these malevolent midges are pretty much the same, even if you’re not sure of the exact type that’s infested your home.
How Do Fruit Flies Get In Your Home?
Fruit flies get into your home by…flying in. No, seriously.
“More often than not, they’re coming in from the outside,” says Dan Dilworth, a restaurant operations director and alumnus of Danny Meyer’s Union Square Hospitality Group who’s opened several dozen restaurants, from fine dining to fast-casual. “A lot come in through loading docks. Like a giant garage door, they will seek out anything not cleaned recently, anything sugary…They tend to gravitate toward floor drains that accumulate gunk and yummy things for fruit flies.”
Keck says that in residences, fruit flies often get sucked in through open exterior doors or windows, though they’re not small enough to squeeze through a typical screen. They’re often found outside of houses feeding on decaying vegetation—like grass clippings or dead plants—that appears after a big freeze or some weather-related incident, before making their way inside when you unwittingly invite them in.
Fruit flies can also enter your home before they even hatch—via eggs attached to the outside of fruit you buy at the store—but there’s not much you can do about that unless you’re willing to inspect every square micrometer of your fruit under a microscope every time you come back from the market.
“You’re not going to be able to see them,” says Keck. “They’re probably the size of a grain of salt or something like that.”
How Do You Prevent Fruit Flies?
Fruit flies are the symptom of an issue—not the actual issue itself. And the issue in question can range from basic cleanliness and sanitation to simply bad luck.
“If you see a lot of fruit flies [in someone’s kitchen], it’d make me look closer at the other practices the person is doing,” says Dilworth. “It’s one of those tells when the health inspector walks in and sees fruit flies. It’s an indication, especially if there’s not ripening fruit out, [that] you’re not cleaning drains and wiping down food surfaces.”
Serious Eats / Vicky Wasik
Fruit flies look for food, which mostly means sugar. Rotting or fermenting fruit or vegetable matter acts like a beacon telling the flies that sugar’s available—and so does any nasty sludge that accumulates around sinks, drains, toilets, tubs, showers, and under cracked tiles. Some small flies we think of as fruit flies, like fungus gnats, are attracted to and lay eggs in the fungus found in the soil of potted plants.
“For any fly, it’s about the source: control the source, [find] the source, reduce the source, get additional sources out of the environment,” says Keck. “They’re there to lay their eggs in the source. If that’s gone, they’ll go away as well.”
Here’s where the type of flies you have can play a small role in determining your strategy.
“The ultimate way to get rid of them is to get rid of the food source,” says Keck. “The fungus gnat may be in plants, drain flies will be in the gunk around the drains, » she adds, so identification makes it easier to narrow down what type of fruit flies you may have.
If you find that you have fruit flies or other similar pests, you should be regularly cleaning drains and sanitizing them, says Dilworth. “Continuously wipe down surfaces and sanitize them regularly. Keep aromatic fruits and vegetables out of the open, or keep them really well sealed off or in a refrigerator. [Fruit flies] love bananas and tomatoes, but any fruit you leave out to ripen at room temperature will attract them. If it’s hot and there’s sticky fruit out, they will come.” If you’re composting, you’ll want to remove your food scraps and composting bags as soon as you can.
“Move compost bins away from doors and windows,” says Keck. “Take the trash out regularly. And if you are recycling, or even not, and you have Coke cans, beer cans, wine bottles, rinse them out before you put them out—that little hit of fluid at the bottom is a lot for those guys to sustain themselves on.”
For fruits and vegetables that shouldn’t go in the fridge, like bananas and tomatoes, place them in brown paper bags and tightly seal them with a clip. If you’ve got fungus gnats, eliminate the contaminated soil and repot the plant.
In addition, Keck says it also helps to keep the outside of your house well maintained, since that’s where most of the fruit flies will be coming from. Remove dead vegetation, grass clippings, and any nasty slime and gunk that accumulates around dead plants, which are basically like an all-you-can-eat fruit-fly buffet. But understand that if you have a fruit fly problem one spring, you’re likely to have the same issue next spring because of the cycle of weather and the vegetation in your yard, she says.
And, finally, keep your doors and screens closed and sealed tightly as much as possible.
How Do You Get Rid of Fruit Flies?
If you already have fruit flies and want to get rid of them ASAP, you can try various age-old tricks. A popular one that both Keck and Dilworth recommend involves partially filling a jar with apple cider vinegar and a couple drops of dish soap, wrapping the mouth of the jar with plastic wrap, and poking a few holes in the wrap. (Fruit flies can crawl into the holes in the plastic wrap but can’t figure out how to get back out.) The flies will be attracted to the smell of the fermenting fruit juice and crawl in without being able to get back out; the soap will cut the surface tension so they drown. Apple cider vinegar works best due to its sweetness, but other vinegars may work well, too.
You can also buy commercial sticky traps, which will also attract fruit flies and prevent them from escaping.
Of course, the traps only take care of the adult fruit flies. If the pests have already laid eggs somewhere inside, you’re just going to have to deal with the next generation all over again in a week or so. So you’ll want to make sure to clean your home and eliminate the flies’ food sources out in the open as much as possible.
If you’ve overwatered your plants or brought plants inside, perhaps over the winter, your issue may be fungus gnats that are attracted to the fungus that has infected the soil, whether or not you can see it yourself. Repotting the plant and throwing out the old soil usually does the trick, says Keck.
If you suspect you have drain flies, you’ll need to clean the drains, sinks, and garbage disposals—which involves more than pouring bleach or boiling water down there, since that’s not enough to get rid of the organic slime the flies are feeding on and laying eggs in.
“Drains are a big issue in a home,” says Keck. “If you suspect the issue’s a drain, place double-sided sticky tape on half the drain and don’t run any water in it and leave it overnight. If they’re stuck to it in the morning, then you know it’s the drain. Enzymatic cleaners will get rid of that gunk.”
You can buy enzymatic drain cleaners at hardware stores or online, including ones from popular brands like Zep, Green Gobbler, and Amazon.
Fruit flies, drain flies, and fungus flies only live a couple weeks, so once you’ve treated your space for the adult flies and taken all the preventative measures necessary, especially eliminating food sources, you should see the problem diminish in a few days, and then abate entirely in a week or two, says Keck.
The Takeaway
Fruit flies are everywhere, and it’s inevitable that you’ll have to deal with them at some point. But by taking basic, regular cleaning steps and eliminating the flies’ food sources, you’ll be able to stamp out any infestations quickly. Make sure to maintain the outdoor areas of your home to prevent fruit flies from coming in. Keeping drains and surfaces clean, sealing off or refrigerating fruits and vegetables, and regularly taking out trash, recycling, and compost are key to preventing fruit flies from invading your home. And if you’re already dealing with an infestation, the apple cider vinegar trick or a commercial sticky trap should be enough to catch these little pests.
