This tiny bugs can surely be annoying, but what is the difference between a gnat and a fungus gnat?
It’s a bit of a challenging question to answer, as the term “gnat” can be used to apply to all sorts of flying bugs – generally the smallest ones that do not bite. There are many species of gnat throughout the world, and the fungus gnat is one of them.
However, there are differences between most gnats, such as fruit flies and drain gnats, and fungus gnats. We’ll explore some of the differences and similarities so you get a sense of what makes a gnat a fungus gnat, and what doesn’t.
Knowing what kind of gnat you’re dealing with can make it much easier to get rid of them when they are proving a nuisance. If you don’t know what the gnat is, you may struggle to work out how to get rid of its food sources.
Fungus gnats live in plants, so knowing how to identify them can be useful, especially if you have a lot of plants in your home. We’re going to cover what they look like and how they behave so that it’s easier for you to work out what kind of gnat you’re dealing with, and how to get rid of it.
What’s The Difference?
Many small flying creatures will look much the same until you get up close. They are so small and often move so quickly, it can be hard to detect much visible difference between the many kinds of gnat.
However, if you get up close to one – particularly one that has landed – you should be able to see more clearly what kind of gnat it is.
Firstly, let’s cover what a fungus gnat looks like. These little bugs are usually dark gray or black, and they are very small. They look rather like tiny mosquitoes, with long, dangling legs and elongated bodies.
The larvae of fungus gnats probably aren’t something you’ll see unless you dig around in the soil of your houseplants, but just in case, these are little white or semi-transparent worm-like creatures with black heads.
Fungus Gnat vs Fruit Fly
Let’s compare a fungus gnat to a fruit fly, another common kind of gnat that you are likely to see drifting around in your kitchen.
Fruit flies are usually a tan sort of color, rather than the black or gray of a fungus gnat. Some fruit flies are quite dark, but the color can be a good indication of their species. If you compare pictures of the two online, you may get a better idea of a fungus gnat vs a fruit fly in terms of color.
They also differ somewhat in terms of their body shape. Fruit flies are not as elongated as fungus gnats, and look more like traditional house flies. They are a little rounder, and their legs don’t dangle as noticeably as a fungus gnat’s legs.
Finally, if you’re still unsure, you may notice that fruit flies have very distinctive “fly” eyes. Their eyes are often somewhat red, whereas you will not be able to see the eyes on a fungus gnat clearly, as they are just too small.
Fungus Gnat vs Drain Fly
How about fungus gnats compared with drain flies? A drain fly – as the name suggests – is usually to be found around sinks or drains, and you might find them hanging around a sink with food clogging up the pipes, or unused sinks in particular.
A drain fly is similar in size to a fungus gnat and fruit fly, but it is a little more moth-like in appearance. Their antennae tend to be more visible and are fuzzy, and they usually have a dark border around their wings.
You are unlikely to see drain flies around in the general room; usually, they stay close to the drains they are living in, and will even lay their eggs in the pipes, feeding on the waste below. Fungus gnats, by contrast, are usually to be found near plants.
Fungus gnats lay their eggs in the soil, and will spend a lot of time swarming around any damp earth that they can find. They are often attracted if you over-water your plants, as they thrive in moist environments. You will not usually see a fungus gnat near a drain or near ripe food.
Fruit flies, however, are usually found in or near ripe fruit, and won’t show much interest in plants or drains. They will occasionally swarm in other moist environments, especially if their food source has been removed, but on the whole, you won’t see them in the same places as the other two kinds of gnats.
Fungus gnats also differ from fruit flies and drain gnats in that they are not generally very interested in human food – although they will likely eat it if they get the opportunity. They usually prefer soil, as this gives them a good breeding ground for their eggs.
A final difference is that fungus gnats are potentially more damaging than the other two. Though none bite or sting or pose any threat to humans, fungus gnats do pose a threat to your plants. The larvae eat organic material in the soil, and that can include the roots of your plants.
If you have a serious fungus gnat infestation, you may notice your plants getting pale and sickly, and possibly even dying. By contrast, fruit flies might spoil some of your food, but they and drain gnats are relatively minor annoyances, and are unlikely to do any major or frustrating damage.
This may mean that you want to address problems with fungus gnats quickly, rather than risking them doing too much damage to your plants.
Where Are They The Same?
In terms of looks, they do all share some similarities. They are usually something like one eighth of an inch in size, and they all fly around in a zigzagging, confusing motion. Their wings are generally the size of their bodies, and they have six legs.
They are also all usually quite dark in color, although they may vary a bit. It can be hard to detect the color variation unless you look while the gnat is motionless, as they are often so similar it’s indiscernible while they are flying.
You may see all three species swarming, as usually there will be a lot of them. They tend to breed fast and you can easily end up with large amounts of gnats if there is a good food source. You are less likely to see drain flies swarming as they do tend to stay in the drains, but if something brings them out, it may happen.
Gnats all share a love of wet habitats, so all three can be discouraged by making your house drier and removing damp spaces (though obviously this can be a challenge with your drains). You are likely to see fruit flies and drain flies if you have ripe food or food residue in your pipes.
Most people would agree that where fungus gnats are the same as other gnats is that they are equally annoying, particularly when they swarm. This kind of bug is often keen to fly right into your face, attracted by the moisture on your breath, and this can be highly unpleasant, especially if you breathe them in.
How Can You Tell?
Although the three look different close up, it can be very hard to see the difference from a distance, meaning you will often have to wait for them to settle before you can tell. You may need to use a magnifying glass to get a proper look at the kind of gnat you’re handling.
An easier way to tell the difference is to watch the gnats’ behavior. Gnats that hang around flower pots and any other soil in your house will almost always be fungus gnats, as fruit flies and drain flies don’t have any particular reason to swarm around the soil.
Remember that damp soil attracts gnats, and you may see other kinds of gnat settle on soil for a drink sometimes, but they are unlikely to hang around for long periods of time, whereas fungus gnats like to mate and breed near the soil they will lay their eggs in.
By contrast, if you notice the flies settling on ripe food, they are likely to be fruit flies. Remember that fruit flies do not only eat fruit; they will go for other kinds of food if they come across it, especially if their original source of food has been removed.
Fruit flies may seek other moist environments if they can’t find food, so you might also see them around your sinks, or clinging to damp sponges, mops, cloths, etc. They need moisture to survive, and if they aren’t able to find food, they will look for damp areas to settle in while they wait.
Gnats that are consistently hovering around your drains are probably drain gnats, and may need to be dealt with in different ways to effectively get rid of them. You might also see them landing on food in your kitchen if they are out of the drain, but often, they will eat waste in the pipes, rather than fresh food.
What Should You Do If You Find One Or The Other?
If you find gnats hanging around in your home, the first thing you should do is try and work out what they are, or at the very least, what they are eating and where they are breeding.
There are hundreds of species of gnat, so you may not be able to determine exactly what kind they are, but working out what they depend on for food and egg-laying will help you decide how to deal with them.
If you don’t check what you are dealing with, you might spend ages trying to find overripe fruit, only to discover the gnats aren’t particularly interested in that!
The first thing you should do when you notice a swarm, therefore, is watch to see what they do. If you see the flies settling on fruit or other food, but paying minimal attention to your drains or your houseplants, you can guess that they are fruit flies.
The next thing to do, if possible, is to get a closer look to confirm this impression. Once you have decided that they are fruit flies, you should look at getting rid of any moldy food, covering anything you cannot get rid of, and putting other food away.
Next, minimize the moist areas available. Mop up water spills, wring out sponges, and dry countertops and around the sink. Fruit flies will quickly disappear if they cannot find food or water.
Drain flies can be a little trickier to deal with, but you may find that pouring bleach or other cleaning chemicals, or possibly boiling water down the drain is a good solution. Most drain flies depend on stagnant water and being undisturbed to survive, so once you’re aware of them, you should find it fairly easy to get rid of them.
Fungus gnats may be the hardest of the various kinds to get rid of, because they usually have eggs and larvae in the soil, and even if you manage to get rid of the adults temporarily, their eggs will continue hatching and breeding.
It is best to deter fungus gnats if you can, and this can be done by not over-watering your plants. Remember that the gnats like a moist environment.
If you have already got fungus gnats, you will need to find ways to deal with them – and we’re going to run through a few potential options that may help.
Firstly, allow the soil in the pot to dry out as much as possible without harming the plant. This will either kill the larvae, or at least make the environment less hospitable to them. If your plants are drought-tolerant, you may be able to let the soil dry out enough to get rid of the gnats entirely.
However, you may be worried about damaging your plants by not giving them enough to drink. Moving them to a sunny spot may help deter the gnats, as it will make the environment hotter and less tolerable.
Neither of these options will get rid of the gnats quickly, but they will slow down their breeding cycle and may eventually cause them to disappear.
Alternatively, if you are really having problems, you might have to consider repotting your houseplants, using fresh soil that is free from gnats. You will then need to be careful to avoid over-watering, or you will end up in the same position.
You should repot all plants in a room at once – otherwise other plants that are in close proximity may reinfect your freshly potted plants. Discard all the infected compost, rinse the roots, and then allow the roots to dry out a bit (but not a lot).
Be very gentle while doing this so you don’t damage your plants. Most people try to minimize compost removal when repotting, but you will need to get rid of as much as possible to get rid of the gnat larvae.
If you have plants that do not like being repotted, removing some old compost and adding a bit of fresh soil (minimizing disruption around the roots) can still help reduce the problem, but may not solve it entirely.
Wash your plant pots and then put fresh soil in them. You may want to mix some sand or gravel into the soil to maximize drainage, as this will also help to make the soil less hospitable to the gnats in the future.
Repot the plants in the fresh compost, and then return them to the house. If you still have adult gnats around, it is best not to put the plants in the same room until these gnats have dispersed, or you may be back to square one!
Another technique that may help is to water your plants from the bottom. Instead of pouring water on top of the soil, add it to the tray or saucer that your plant stands in, and let the soil just soak up what moisture it needs.
This can help avoid over-watering, but you should still keep an eye on your plant and not add more water to the tray until the quantity that you put in to start with has evaporated completely.
Essentially, when you find any kind of gnat, you need to look for the source of food, the breeding ground, and any sources of moisture. Getting rid of any or all of these will help to deter the gnats and get rid of them.
In short, fungus gnats are not the same as other gnats, although they are similar in terms of looks and needs. You should now have a good idea of how to recognize fungus gnats vs other gnats.
Gnats that hang around your plant pots are almost certainly fungus gnats, and pose some danger to your plant roots, so they should be dealt with as soon as possible.
For more about gnats and similar insects check out these links:
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