There are many different kinds of gnats in the US: Buffalo gnats, eye gnats, fungus gnats, gall gnats, and gnat bugs. They are considered pests as some species bite humans (for blood) while others damage the roots of plants. If you’re wondering how to catch them to see what’s living on your property, I’ve written a handy guide to help you out.
Gnats are attracted to light. They can distinguish between light in different wavelengths as they have photoreceptors. Ultraviolet light is the most attractive to gnats, followed by green-yellow, in both daylight and darkness. Colors in the violet-blue range aren’t as appealing to gnats.
I’ll cover whether gnats are attracted to light in extensive detail and how to catch them using lights. In this guide, I’ll also talk about other methods you can use to catch these insects. You’ll also learn whether you can use bug zappers and the potential breeding grounds for gnats.
Do Lights Attract Gnats?
It’s common to see insects flying around a street light at night. If you leave your window open and switch on the lights, you’re bound to see several insects inside your room within a couple of hours.
You may also see them on your computer monitor or TV, or perhaps even hovering around your lamps. As gnats are also insects, does this mean they respond to light?
Gnats are attracted to light as they have photoreceptors. These are special neurons responsible for giving living beings the ability to perceive color with their eyes. In fact, gnats are able to differentiate between light in different wavelengths. In other words, they know the difference between ultraviolet light and violet-blue spectra.
Research has shown that gnats find UV light the most attractive of all the wavelengths in the light spectrum.
Out of the other colors, green-yellow was the second most attractive to these insects. However, they only found this wavelength appealing during daylight.
Gnats can also differentiate between high-contrast subjects. This allows them to locate darker areas, which they can use to lay eggs and propagate their species.
How To Catch Gnats?
Bad news is, gnats are attracted to light. Good news is, gnats are attracted to light. Now that you know that gnats have photoreceptors and are attracted to light, you can use this fact to your advantage in order to catch them with ease.
Here are a couple of effective ways to catch gnats with light.
UV Light Traps (Blacklight Traps)
As you already know, UV lights are a great way to attract gnats. You can get them to come to a specific location with simple traps. Below are two different UV light traps you can use:
1. Bedsheet UV Light Trap
If you are looking to take a closer look at the gnats on your property, this method is a cost-effective solution and easy to execute.
All you need is a white bedsheet and a UV light source. You’ll need to be outside your house to create this trap (unless you don’t mind these insects getting inside your home).
Find a place to hang the bedsheet, such as a clothesline. Suspend the UV light on top of this sheet. If there is any leftover sheet, fold it towards the light. A fold helps catch any insects that fall off the sheet. Make sure all parts of the sheet are within your reach.
Leave this overnight and take a look at the sheet in the morning. If gnats are living on your property, you’ll find them on the sheet. Always protect your eyes, ears, and hands by wearing appropriate protection before handling these insects.
You can also leave the UV light on in the morning to catch gnats.
However, you’ll also see other insects on the sheet, as UV light attracts various types of insects. If you only want to catch gnats, you’ll have to be able to identify them properly.
2. Modified Yellow Sticky Traps
A common way to catch gnats is to use yellow sticky traps as yellow attracts these insects. Although they are excellent for trapping insects, you can improve them even further with a simple trick.
Attach a UV light to the yellow sticky trap to increase the number of gnats you catch. Most of the yellow sticky tracks in the market don’t reflect UV light. Even if they do, they don’t have the same intensity as standalone UV lights.
Both of these methods will help you catch adult gnats. However, you may also encounter helpful insects in your traps. As they help maintain a healthy ecosystem with plants on your property, avoid harming them at all costs.
Without UV Lights
Even if you don’t have UV lights, you can still catch gnats with the following methods. Use one of the following traps to capture gnats.
1. Potato Piece Trap
Note: Only use this method to catch gnat larvae as this isn’t effective against adult gnats.
For gnats to survive, they require access to moist and shaded areas, especially those you find under organic material like mulch.
When adult gnats find favorable conditions on your property, the female insects lay eggs in your soil.
Once the eggs finish hatching, the larvae go through the soil, looking for food. They damage the roots of plants, limiting their growth over time. If large populations of gnat larvae are present in the ground (due to an infestation), they can kill the plants.
Fortunately, it’s relatively easy to catch the larvae. Cut a potato into several pieces and bury them in the soil.
This takes the attention of the gnat larvae away from your plant roots and focuses on the potato pieces.
After 2 to 3 days, check the potato pieces. If you spot any gnat larvae on them, dispose of the bait immediately.
You can replace the old ones with new pieces and repeat the process to reduce the number of these larvae from becoming adults.
2. Sugar and Wine Trap
Humans aren’t the only ones who like drinking wine. If you have an old open bottle of wine, you can use it to catch gnats.
To create this trap, all you need to do is to open the wine bottle and cover the opening with plastic wrap. Make a hole large enough for the gnat to enter the bottle. Once they’re inside, they won’t be able to leave the trap.
Although the smell of wine attracts gnats, you can improve its effectiveness easily. Add sugar to the wine and allow the mixture to ferment.
Once it develops a strong scent, you can use this trap to catch gnats. Spread multiple traps around your property to attract these insects.
Wait for at least a day or two before you remove the traps. Discard the solution with gnats, add fermented wine with sugar, and you’re good to go.
3. Apple Cider Vinegar Trap
If you have a bottle of apple cider vinegar in your house, you can use it to attract gnats. Find a container you don’t mind using to trap these insects.
It’s preferable to use a container with a narrow neck. This makes it harder for the gnats to escape from the trap.
Cover the container top with plastic wrap. Make several holes in the plastic covering, allowing the gnats to enter the trap. Make sure the holes aren’t too big so the gnats can’t escape once they’re in.
If you only want to catch insects, this method will suffice. You can also use this technique to eliminate gnats with a slight modification.
Add a few drops of any liquid dishwashing soap to the apple cider vinegar trap. Soap increases the surface tension, preventing the gnats from escaping once they touch the liquid. The insects will sink into the apple cider vinegar mixture and drown.
4. Ripe/Damaged Fruit Trap
Another item gnats can’t resist is ripe and damaged fruits. You can design a simple and effective trap using kitchen ingredients.
Find a container you don’t mind using to create this trap. Again, it is helpful if the neck is narrow. However, this design may make it harder to place the fruit inside the container.
Cut any ripe/damaged fruit and place it inside the container. Use plastic wrap to cover the vessel. Make big holes, allowing the gnats to pass through.
Create multiple fruit traps and place them throughout your property. Wait for a few hours before checking on the traps.
If you want to keep using these traps, replace the ripe fruits.
Can You Use a Bug Zapper To Catch Gnats?
Is there another way you can catch gnats without spending hours setting up the traps around your house?
You can use bug zappers to quickly get rid of gnats inside your house. While bug zappers are an excellent way to attract gnats and eliminate them, keep in mind that you’ll likely end up killing many bugs other than gnats.
As highlighted earlier, UV light attracts many insects. Bug zappers will zap any insect that is attracted to them, including those that may be helpful to your home environment. Because of this, you’ll find plenty of dead bugs in your bug zappers–not just gnats.
There are several beneficial insects, such as assassin bugs, honey bees, ladybugs, and pirate bugs. They protect your plants from predators and help during the pollination process.
Wiping these beneficial insects puts your plants at risk of suffering from a bug infestation. It can also lower the yields of your plants.
Where Do Gnats Come From?
If you spot gnats on your property, you might wonder where they’re coming from, especially when you use the above methods to catch them.
However, if you wish to eliminate them completely, you need to go to the root of the problem. Killing or catching gnats once they’re in your home isn’t a permanent solution–you need to target them while they’re larvae. As they lay eggs quickly, it can become an uphill task to keep catching these insects if you don’t intervene in the larva stage.
Generally, gnats love moist and shaded areas of the soil under mulch. Remove the mulch and dry the soil by removing moisture. To do this, avoid watering the soil for several days. Make sure you pay special attention to the plants as you don’t want them to die.
Overwatering is another reason that attracts gnats to your property to lay eggs. Follow proper watering techniques to prevent water from accumulating.
It’s also possible for gnats to come from the drain. This happens because there is decaying food in the pipes, attracting insects inside your house. You can get several cleaning products from your local supermarket to clean the drain pipe and remove any food debris.
Gnats can also grow in ponds and rain gutters. Always check the rain gutter for clogs and remove all debris to allow water to flow freely.
If you notice any water accumulating on your property, check for leaks. Correcting this issue will ensure that the gnats don’t find your property a suitable breeding ground.
These insects can also come from the infected soil of indoor plants. For instance, you may notice many larvae in the pot when you water the plants. In this case, you’ll have to let the soil dry to reduce the number of larvae.
Alternatively, you can also go for pasteurized soil, which is free from insects. You can do this at home, but you’ll need an oven to heat the soil up to 180 °F (82 °C) for a minimum of 30 minutes.
Gnats are attracted to light, especially in ultraviolet and green-yellow wavelengths. They have a short lifespan, enabling them to infest your property quickly. UV lights with a bedsheet or yellow sticky paper make it easy to catch these insects. However, these lights also attract other insects, so pay close attention to the trap.
You can also create traps that don’t require light with ingredients such as apple cider vinegar, potatoes, ripe fruits, sugar, and wine. Avoid using bug zappers as they also affect helpful insects.
- ScienceDirect: Photoreceptors
- PennState Extension: How to Pasteurize Medium and Sterilize Containers and Tools
- NYTimes: Do Bug Zappers Work? Yeah—About As Well As Any Other Indiscriminate Wildlife Slaughter.
- National Park Service: Gnats
- Cornell CALS: Fungus Gnats
- Texas A&M: Indoor Flies and Their Control
- University of Florida: Eye Gnats
- Harvard University: A Fly’s Favorite Color
- DIY Pest Control: How to Get Rid of Gnats
- Iowa State University: Watch for Fungus Gnats in the House and Take Action if Found
- University of Kentucky: Midges and Gnats
- NC State University: Fungus Gnats Indoors
- Luomus: A review of Estonian wood gnats (Diptera: Anisopodidae)
- MDPI: Ecology of Fungus Gnats (Bradysia spp.) in Greenhouse Production Systems Associated with Disease-Interactions and Alternative Management Strategies
- Hannover University: LED based trapping of whiteflies and fungus gnats: From visual ecology to application
- Wikipedia: Gnat
- Texas A&M: Bug Hunter
- Florida Bug Club: Insect Collecting 101
- YouTube: Bugs & Black Lights! Attracting Insects at Night
- Mississippi State University: Blacklight Traps
- Healthline: Gnat Bites