As winter sets in, you may notice an unwanted guest. A swarm of gnats in your house during the colder months can be a nuisance. Understanding these tiny insects and their habits will help you effectively deal with them and maintain a gnat-free environment.
Gnats thrive in damp, moist conditions, such as over-watered plants or areas with high humidity. In the winter, these indoor pests seek warmth and shelter, leading to an infestation in your house. There are various types of gnats, such as eye gnats and fungus gnats, which may be responsible for this issue.
To tackle the problem, some common measures to control gnats include:
- Reducing excess moisture in your home
- Regularly removing any damp, decaying plant material
- Avoiding over-watering houseplants
- Utilizing traps, pesticides, or natural remedies
Stay vigilant, and keep your home gnat-free by adopting these preventive measures this winter season.
Understanding Gnats in Your House
Types of Gnats
- Eye Gnats: Non-biting flies in the genus Liohippelates, also called grass flies, eye flies, or frit flies1.
- Fungus Gnats: Slender, somewhat mosquito-like flies about 1/10 to 1/8 inch long, with dark-colored antennae and long legs2.
- Buffalo Gnats: Also known as black flies, small, 1/16- to 1/8-inch-long, humpbacked black flies3.
Life Cycle and Metamorphosis
- Females feed on blood, males on nectar, and plant sap3
Weather and Warmer Months
Gnats are more prevalent in warmer months. In winter, managing gnats in your house can be achieved by adjusting temperature and humidity, removing breeding grounds, and using traps or repellents.
|May affect comfort
|May affect comfort
|Increased cleaning efforts
|Possible side effects
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – No-See-Ums
What bug is unseen to the eyes that invade?
February 2, 2010
What kind of bug bites hard, leaves whelpes, like a rash, but can’t be seen?
Not scappies! I thought dust mites but be treated for that and still have the problem. We thought flees, but have seen none! it’s at night when they attack, we thought maybe a nat or something.
Can you help me? DeAnn
Oh my God! I first thought you were make’s fun of me, then I discover there really is a bug call no-see-ums, lol… Thanks!
Letter 2 – Gnats
We have several houseplants: jades, aloes, hibiscus, etc, which seem to be attracting or generating extremely tiny flying black gnats or fleas that can barely be seen. We have washed down the plants to no avail; the almost invisible slowly flying bugs are still showing up in many areas of the house. Any idea of what this pest is and how we can control or eradicate it? Thanks so much for your help!
Dear T.E. Boston,
My money is on the Black Gnat, Bradysia impatiens. This is a type of root gnat from the Family Sciaridae. The adults are the tiny black gnats that flit in your face while you are watching television and that always seem to get stuck in fresh paint, writes Hogue. He continues "The larva lives in decaying plant material, such as compost, peat, and sphagnum; it also commonly infests the roots and stems of various herbaceous plants. The insects may develop in the media used for potted plants, which explains its mysterious appearance indoors." A mild soapy water used to water the plants might help. Other natural methods to try are an infusion of crushed garlic in water, or nicotine in water. Try soaking some cigarette butts in water and using that when you need to water the plants. The same can be done with the garlic infusion
Letter 3 – Gnats
I live in the midwest and recently relandscaped a good portion of my lawn and had bluegrass sod laid. ok so it was a very warm dry winter then 2 days after sod was laid the spring rains started and just keep coming. Problem is 2 monthes later the rains still come 1 or 2 times a week. there are lots of mushrooms growing in the new sod but that dosen’t bother me i know it will dry up soon. the problem is the sodded area seems to be infested with small dark colored flying bugs larger than gnats but smaller than the average house fly.the sod is still deep green but im worried that this could be a damaging infestation! what kind of insecticide should be used ? can you tell me what kind of bug this could be? thanks in advance!
Many nonbiting gnats including Root Gnats (Family Sciaridae) and March Flies (Family Bibionidae) spend their maggot form eating decaying plant material such as compost, peat and spaghnum. They are scavengers who often live among the roots of grasses. There was probably a substrate of manure and compost laid beneath your sod, and that is where the flies are breeding. They will not damage your lawn as they do not feed on the living grass.
Letter 4 – Gnats
What is the tiny fly type bug that comes in through the window screens and hangs out on the window glass or ceiling. They almost look like a small fruit fly but they are not. They hang out in the grass as if you water your lawn or walk through it they disperse. Just tons coming in the garage screen door. I’ve been swatting them for almost a week now. Live in NY state and it has been dry and hot. Thanks
Any number of gnats are small enough to enter through the openings of window screens. The Black Gnat (family Sciaridae) is tiny, about 1/16 inch, and often flits in one’s face while watching television or gets caught in fresh paint, or causes despair when they appear in bowls of breakfast cereal. The larva live in decaying plant material, often being numerous around compost piles, and they are also known to infest the roots and stems of various herbaceous plants. Since you haven’t complained of itchy bites, you can be thankful that you aren’t being plagued by nasty no-see-ums, so count yourself lucky that you just get benign gnats.
Letter 5 – Hessian Fly
Found this critter in our yard this year (we live in Texas). Sat down on the garden swing and then found we were covered in them. Have never seen one before. Sort of looks like a cross between a spider (the round torso) a fly (the wings) and a mosquito (legs and stinger like head)? Sorry I couldn’t get a closer pic. The camera wouldn’t focus on the bug and not the leafs that close. Haven’t hung around long enough to see if they sting or not.
It is difficult to be certain with your photograph, but I’m guessing you encountered a swarm of Hessian Flies, Mayetiola destructor, an agricultural pest in the Midge family Cecidomyiidae. The maggots do serious damage to wheat plants. Adults are small (1/8 to 3/16 inch long), dark or red-tinged, gnat-like flies with long legs and antennae. The insect got its common name, according to Lutz, when the European insect was first noticed on Long Island shortly after the Hessian troops landed there. It is especially plentiful in Texas. Here is a downloaded Photo by C. Hoelscher.