Fruit Flies vs. Gnats. How Do They Differ?

All the similarities and differences between fruit flies vs gnats and tips on how to get rid of them.
Phyllis McMahon
Phyllis McMahon
Research Writer
Phyllis teaches English Literature at a local college and loves writing in her free time. She’s also a great cook – her British beef Wellington is something the best res read more
Reviewed By
Chas Kempf
Chas Kempf
Expert Consultant
Chas works in a professional pest control company and knows all the nuances of this job. Also, he’s a fantastic tennis player and loves to organize BBQ parties for his fam read more
Last updated: August 22, 2023
MenaceToPests is reader-supported. We may earn a commission through products purchased using links on this page. Learn more about our process here


Aren’t fruit flies and gnats pretty much the same thing? No, not quite. When you take a closer look at fruit flies vs gnats, you’ll find out that, aside from their size, they don’t have all that much in common at all. While both of these little buggers belong to a group of insects called dipterans, their commonalities quickly diverge from there. In this article, we’ll teach you how to spot the difference between fruit flies vs gnats, where you can find them, how long they live, how they even got into your house in the first place, how to gid rid of them, and how to prevent them from coming back.

Fruit Flies and Gnats: What’s the Difference?

As mentioned, both fruit flies and gnats belong to the group of insects called dipterans. Every insect in this group is considered a pest, which is why you’re probably wondering if it even matters what the difference between them is. But it does matter. A fruit fly has a different habitat than a gnat, and they also feed from different sources. Especially when you’re dealing with an infestation, it’s vital to understand whether you’re dealing with a gnat or a fruit fly in order to fight off these tiny pests effectively.

Fruit Flies

Fruit Flies vs. Gnats. How Do They Differ?

Fruit flies belong to either the tephritidae or the drosophilidae, and even among themselves, there are some differences. Most of the time, you’ll be dealing with the drosophilidae, as the tephritidae are mostly known to be a problem in agricultural environments.

Even though drosophilidae is considered a pest, they have a significant purpose regarding research. Because the DNA of the drosophilidae and human DNA is for 61% the same Trusted Source The Fruit Fly in You | Science Mission Directorate NASA-supported researchers are going to send fruit flies to the International Space Stationto learn what space travel does to the genes of astronauts. , and they reproduce very quickly, these particular fruit flies have been invaluable in researching genetics.


If you were to put a fruit fly underneath a microscope, you’d soon realize there aren’t many similarities between fruit flies and flies. Even when comparing gnats vs. fruit flies’ size, your first impressions were probably off. A fully grown fruit fly only measures about 1/8 inch Trusted Source Fruit Flies | Entomology in length, making them much smaller than gnats, and its antennae are much shorter as well. In a sense, a fruit fly looks like a miniature version of the common huis fly, with their round silhouette and big red eyes. The color of their tiny bodies can range from a light tan to full black.

Life cycle

Once you’ve spotted a fruit fly in your home, it’s important to take immediate action. While a fruit fly can survive for up to three months when the conditions are right, its typical life cycle lasts for only 30 days. In that time, they can wreak a lot of damage, given how the female fruit fly can lay up to about 400-500 eggs in as little as 10 days. She lays her eggs in fermenting vegetables and fruits.

Fruit fly eggs can hatch within 12 hours of being laid, after which it takes about 10-14 days for the fruit fly to mature into an adult. They feed on the fungi that is present in the fermenting food that they were laid in. Larvae go through several molting and turn into adults after the pupa phase. Fruit flies start mating soon after they reach adulthood.


Fruit flies didn’t get their name without reason. They love rotting food and overripe fruit, which is why you’ll usually first notice them around your fruit basket. But they can also find their way into potato bags, or even your dirty mop, as the larvae live on the fungi of rotting food. Most of the time, you’ve brought infected goods home from the grocery store. If you grow your own fruits and vegetable, you’ve probably taken the little buggers inside without realizing it.


Fruit Flies vs. Gnats. How Do They Differ?

Commonly simply called gnats, their full name is actually called fungus gnats, and there are some important differences when looking at fruit flies vs. fungus gnats. Fungus gnats belong to the suborder Nematocera and can be further divided into the Anisopodidae, Mycetophilidae, and Sciaridae. Most of the time, the gnat you stumbled upon will belong to the latter group of Sciaridae.


At first glance, gnats actually have a lot more in common with mosquitos than fruit flies. When comparing fungus gnats vs. fruit flies, you’ll soon realize that gnats have a small, pointed body, as opposed to round, and they measure up to 2mm long. While fungus gnats are typically brown in color, they can also be black or yellow. Compared to their body, the wings of fungus gnats are relatively oversized, with large, spindly legs that make them look like mosquitos. These legs are also the reason gnats are capable of jumping pretty high and flying at incredible speeds.

Life Сycle

Just like fruit flies, the fungus gnat has an average lifespan of about 4 weeks and also goes through four stages; egg, larvae, pupa, and adult. The female gnat is able to lay about 100-150 eggs in the week that an adult gnat survives, which is considerably less when fruit flies vs. plant gnats are juxtaposed. Usually, they are found in strings of 3 to 40 on top of moist soil. Once hatched, it takes about 10 days for the larvae to reach the pupa stage and 4 more days until the fully grown fungus gnat emerges.


While fruit flies are found in food and vegetables, the fungus gnat is mostly found in the soil of gardens or potted plants. They feed on organic matter, which is why fungus gnats can also be found in dirty drains or even the drip pain underneath your fridge. The fact that the fungus gnat can make their home in drains is why some people may refer to these little creatures as sewers or drain gnats. Likewise, fungus gnats can be residing in your garbage disposal or sink drain. Any place where organic matter can be found is a possible home for an infestation of fruit flies or sewer gnats to take hold.

You’ll often find them in relatively warm places, especially in places where stagnate water can be found. Fungus gnats are never alone, so when you find one, it’s can be guaranteed there are many more to be found.

As you can see, aside from their physical appearance, the habitat of the sewer gnat vs the fruit fly is vastly different. This is why it’s so important to learn the difference between drain gnats and fruit flies, so you can effectively combat them and keep them away.

How Did They Get Inside?

Fruit Flies vs. Gnats. How Do They Differ?

It’s not the most comforting thought, but as far as plant gnats vs. fruit flies go, the reason they found their way into your home is probably that you brought infested produce or plants inside yourself. Infested fruit from the grocery store, and potted plants that already have eggs or even larvae in them, are the usual culprits for inside infestations of fruit flies and gnats alike. If you grow your own vegetables, they may have gotten an unintentional lift from your own garden into your kitchen as well.

Gnats love to take root in potted plants because they are often moist. Once the plant is transported inside, it’s only a matter of days before an infestation has grown on the inside of your house, despite gnats preferring the outdoors. As sewer gnats life in dirty drains, it’s also very possible they simply took the opportunity to slip inside the ‘regular’ way as well.

How to Get Rid of Fruit Flies and Gnats?

Now you know how to recognize fungus gnats vs. fruit flies vs. drain flies and that they are found in different places. And while they look quite similar to the unknowing eye, there are still some differences when it comes how to get rid of gnats vs. fruit flies.

How to Get Rid of Fruit Flies?

Once you’ve spotted fruit flies in your home, it’s important to take immediate action. Because of their short life cycle, you’ll have a fully fletched infestation in no time, which would be a shame, as there are simple ways to prevent this escalation to occur.

Remove the Food/Breeding Source

First, make sure you remove the food source and clean thoroughly. Not only does this make sure the fruit flies no longer have something to sustain themselves with, this is also where the female fruit flies have laid their eggs. By removing the food source, you make sure no new fruit flies will hatch. This includes your garbage disposal and the bottom of your bin, where vagrant bits of food can also be the source of your problem.

Checkpoints of Entry

You probably brought your unwanted guests with you with your groceries, but just to make sure they haven’t been inviting themselves in, it’s pertinent to check your doors and windows. If you have screens installed, ensure that they’re all still intact. If you don’t have screens, maybe it’s a good idea to install them.

Set Traps

While the above-mentioned steps are important, you don’t want to leave any live bugs behind. There are lots of good fruit fly traps out there, just take a look at the best fruit fly traps and choose one that best serves your needs. If you don’t trap the ones already flying around, you know they’ll reproduce in no time, and you’ll be right back where you started.

How to Get Rid of Fungus Gnats?

Just like the discovery of fruit flies, it’s important to attack a fungus gnat problem the moment you spot it.

Let Your Plants Dry Out

Gnats are attracted to the soil, especially soil that is moist. Chances are that your potted plants are the root of your problem if you find yourself with a gnat infestation inside your home. The best way to make the soil uninviting is to allow the soil to dry out before watering them again and ensure there is good drainage. Excessive water in the pots isn’t just bad for the roots of your plants, is also helps fungus and mold to grow, which is why gnats thrive in these environments Trusted Source Fungus Gnats Management Guidelines--UC IPM UC home and landscape guidelines for control of Fungus Gnats. .

Use a Repellent

Fruit Flies vs. Gnats. How Do They Differ?

While drying out your potted plants is a cheap solution, it will also take some time for the effect to take hold. You don’t want to sit around and do nothing in the meantime. The best fly repellents are usually also effective in chasing away most flying insects, including fungus gnats. Again, as soon as you notice the infestation, it’s important to take action before the situation gets out of control. And of course, don’t forget to take some preventative measures with you whenever you venture out to your home away from home, in which case something like the OFF! Deep Woods Insect Repellent Aerosol is indispensable.

Are There Ways to Kill Fruit Flies Naturally?

There are a few options if you want to try and tackle your fruit fly problem the natural way. One of the most effective ways is to build your very own apple cider vinegar fruit fly trap. You will need:

  • 1 tbs. sugar
  • 2 tbs. apple cider vinegar
  • 1 cup of water
  • A few drops of regular dish soap
  • A small container

Simply add all the ingredients to the container, mix, and place the mixture in areas around the house, the infected area in specific. Think of your garbage bin, the counter, and wherever you have potted plants. In the fight against gnats vs. fruit flies vs. drain flies, this little mixture will be effective on all of them. The smell will lure them into the container, where they will get coated by dish soap, which takes away their ability to fly.

How to Prevent Fruit Flies and Gnats?

As gnats are mostly an outside pest, all you have to do to keep them outside of your house is ensure they have no points of entry. Install screens, so no unwanted guests enter your house, and check them regularly for wear and tear. It’s said that gnats are attracted to light, so swapping out your white porch light for a warmer, yellow light could keep those pesky buggers away as well.

Because there really not a lot you can do to prevent fruit flies from hitching a hike from the grocery store, just make sure that no fruit gets overripe, and throw any rotting fruit away. Store fruit and vegetables in the fridge to delay the decaying process. Did you accidentally spill something that might get sticky? Clean the surface thoroughly and as soon as possible.

And for those who want to cross every t and dot every i, there are always products like the Fruit Fly BarPro, which not only get rid of any present house gnats and fruit flies but prevent any new infestation from entering your home for a few months as well. These days, there’s a solution for pretty much every problem.

Final Thoughts

At first glance, it’s true that fruit flies and fungus gnats appear very similar. But now you know that there is a clear difference between fruit flies vs gnats that goes beyond their looks. So, next time you spot either one in your home, you’ll know exactly whether you dealing with either fruit flies or fungus gnats, and you’ll also know where to look for their breeding places!


The Fruit Fly in You | Science Mission Directorate
NASA-supported researchers are going to send fruit flies to the International Space Stationto learn what space travel does to the genes of astronauts.
Fruit Flies | Entomology
Fungus Gnats Management Guidelines--UC IPM
UC home and landscape guidelines for control of Fungus Gnats.
Leave a comment

Your email address will not be published. Required fields are marked *