The term gnat is scientifically imprecise and often used to describe any small, annoying fly that travels in swarms or hovers around people like a cloud. Depending on the region, gnat can refer to a variety of tiny flies, some of which bite and others that do not. While some entomologists reserve the term for non-biting species, many people use it to describe biting pests as well—such as no-see-ums or biting midges—which are notorious for their painful and irritating gnat bites. These bites can cause itching, redness, and discomfort, making even a brief outdoor encounter unpleasant.
Whether gnats saw through our skin to extract blood or simply buzz around our eyes and nose, gnats are universally and historically detested. So much so, that Exodus 8:16-18 says that God sent a plague of gnats to torment Pharoah into freeing the children of Israel from slavery. Whether they were biting gnats or simply annoying eye gnats, we will never know, but even in ancient times when this text was written, gnats were reviled and loathed.
Then the LORD said to Moses, “Tell Aaron, ‘Stretch out your staff and strike the dust of the ground,’ and throughout the land of Egypt the dust will become gnats.” They did this, and when Aaron stretched out his hand with the staff and struck the dust of the ground, gnats came on people and animals. All the dust throughout the land of Egypt became gnats.
Many gnats that we consider pests or annoyances play an important role in our environment. Some species aid in the pollination of plants, eat decaying plants and animals, and act as a food source to fish and other animals in the intricate food web.
Generally speaking, gnats are small flies and can be divided into biting flies and non-biting flies. True flies are in the order Diptera, Greek for 2 wings. True flies have only 1 pair of wings but have balancing organs called halteres located at the base of the wings. Flies and gnats can be commonly found in moist environments such as lakes, ponds, streams, marshes, and swamps. Gnats can survive near freshwater bodies of water and saltwater bodies of water.
Gnat Bites
Gnat bites range in appearance depending upon the sensitivity of your body’s reaction and the number of bites you sustained. Bites are most likely to occur on uncovered skin such as ankles and legs, arms, neck, and head. In the United States, general symptoms of gnat bites are redness at the bite site, itchy sensation, and skin irritation. However, if you are in a country where serious diseases are transmitted by biting gnats, boils, ulcers, and even blindness can result from gnat bites. Below are photos of common and not-so-common reactions to gnat bites.
Biting Gnats
Biting gnats are of primary concern for families excited about an outdoor adventure. Mosquitoes are the most common biting flies, but they are not often referred to as gnats. Most gnats do not bite humans, however, some species of gnats require a blood meal to produce viable eggs. Males of these species do not bite, they usually feed on nectar. However, to successfully reproduce, the female of this species must bite other animals to secure their progeny. Mosquitos and biting gnats have very different mouthparts and manners in which they bite. Mosquitos have a needle-like mouthpart which the mosquito uses to pierce your skin then suck up your blood as if through a straw. Most gnats that bite have mouthparts more akin to a pair of scissors with serrated blades and then they lap up your spilled blood. These sawzall blade-style mouthparts cause intense pain when a tiny biting midge decides it requires your sanguine contribution.
Of the biting insects commonly referred to as gnats, the most common gnats that plague humans are the biting midge, also commonly called no-see-ums, the buffalo gnat, and sand fly gnats. Each of these biting gnats can be found in different environments and areas of the country. We will examine each of the biting gnats individually and learn how to protect yourself from their painful bite.
Biting Midge Gnat, No-See-Ums
Biting midges, Culicoides sp, are perhaps better known by their vernacular names. Biting midges are often called no-see-ums, punkies, or sand fleas. No matter what you call them, everyone agrees these aggressive biting gnats are painfully annoying. Dedicated hikers, campers, fishermen, and other outdoor enthusiasts will abandon the most picturesque locations when the no-see-ums are biting. Biting midges are aptly nicknamed no-see-ums because they are so small that you rarely see them until they attack your legs, ankles, and feet.
There are thousands of different species of biting midges, but the majority of them prefer to live in salt marshy areas. The moist mucky areas around ponds, streams, swamps, and saltwater mangroves are the ideal breeding habitat for no-see-ums. They like areas that are wet, but not necessarily under water. The biting intensifies during the calm of the morning and the evening because biting midges are not strong fliers. If there is a breeze, you may experience a respite from their bite. Many people set up fans at their campsite to blow these biters away.
In areas where punkies prevail, special screens are used to keep them outside. No-see-ums are very small, about the size of the sharp pointed end of a pencil, or 1/16”. The holes in typical window screens are larger than the critter you are trying to keep out. Therefore, no-see-um screens and nets can be applied to campers, tents, picnic table covers, and homes in areas of high biting midge activity. This special screen has a smaller mesh size, which does inhibit air flow but keeps no-see-ums out.
The bite of a biting midge is sharp and painful. Because they live and breed in the organic matter on the earth’s surface, they usually attack the exposed skin of your feet, ankles, and legs. The painful bites accumulate quickly and form small red welts or bumps. These bites are intensely itchy and painful and may take a week or two to heal completely.
In the United States, biting midges are simply a painful annoyance, but in other countries, they are associated with disease. In tropical and subtropical areas of the world, biting midges can pass filarial worm larvae to humans. These worms develop under human skin or in the lymph tissue, causing illness. Biting midges can also pass diseases to sheep, cattle, and horses.
Pest Control for No-See-Um Gnats
Controlling efforts for biting midges, or no-see-ums, is not an easy task. No-see-ums live and breed in and about waterways. Pesticides may not be used in the areas where no-see-ums breed. Applying pesticides to salt marshes or mangrove swamps is likely illegal and would harm the natural aquatic environment.
Control efforts targeting the biting adults are usually ineffective for long-term control. While a spray application may lessen the biting midges on a particular evening, it will have little effect on subsequent evenings. No-see-ums have a rapid life cycle and are continually leaving their marshy habitat and invading areas of human activity. Controlling no-see-ums at the adult phase would require daily spraying, which is not recommended. Many local governments of coastal communities have mosquito spraying programs and field many complaints about no-see-ums. Most local governments do not engage in no-see-um control and are unable to provide services against these biting gnats.
The best protection against these aggressive biting gnats is physical barriers. While in these enticing coastal areas, many people wear flip-flops and shorts. However, the most experienced adventure seekers are often wearing sneakers, socks, and long pants to avoid the bite of the no-see-ums. In addition, mosquito repellent containing DEET is labeled to repel biting midges. For a DEET-free option, a repellent containing lemon and eucalyptus oil has shown promise in keeping no-see-ums at bay. If you have access to electricity, set up fans to circulate the air around you. This helps to push the no-see-ums away from your immediate vicinity and provide a small, safe room.
Buffalo Gnat, Black Fly, Bull Gnat Bites
Black flies, of the family Simuliidae, are known by many names. As the name black fly suggests, they are black in color. Many people call refer to these biting gnats as a buffalo gnat because the hump on its back resembles the hump on the back of a bison. Other common names for this biting gnat are the bull gnat and the turkey gnat. Regardless of the name you give this biting gnat, worldwide, they cause much devastation as they are the vectors for the parasite that causes River Blindness.
Buffalo gnats prefer to breed near fast moving rivers and streams. In the United States, outdoor enthusiasts are those most at risk of encountering the bite of black flies. Black flies live almost exclusively in or near the water from which they hatched. After a female buffalo gnat has secured a blood meal, she lays eggs in or near a flowing water source. One female buffalo gnat will lay between 150-500 eggs in her lifetime. Most buffalo gnats overwinter at the egg stage. When they hatch, the larvae attach themselves to underwater rocks with silk. The black fly larvae have a fan-like structure on their head with which they capture their meals such as algae, bacteria, pollen, and other organic matter. After a time, these larvae enter an underwater pupa or cocoon and emerge as adults in a bubble of air. Adult buffalo gnats usually stay close to the waterway from which they emerged and are, therefore, ready to bite when people or animals come near the river bank. Buffalo flies are more temperature-dependent than the no-see-ums often encountered in Florida. Once the water temperature reaches about 70℉, the eggs stop hatching and adult populations naturally decline.
Like mosquitos and other biting gnats, it is only the female buffalo gnat that bites. She requires blood from another animal to lay viable eggs. While the bite of a black fly or a bull gnat is painful and annoying to humans, it is not deadly to us here in the United States. However, these biting gnats can accumulate in such large numbers that they have been known to get into the respiratory tracts of domesticated chickens, causing them to suffocate. They are so bothersome to livestock that occasionally, these buffalo gnats incite a stampede, causing smaller animals to be trampled.
As concerted efforts to clean up our waterways have been successful, black fly populations have increased. Cleaner bodies of water have allowed the black fly population to flourish in recent years.
Pest Control for Buffalo Gnats
Because they live and breed in water, controlling buffalo gnats at the early stages is impossible. Strict regulations regarding pesticides in or near water prevent the treatment of buffalo gnat breeding grounds. The negative effects of such a practice could have a devastating effect on fish and the general health of our rivers and streams. Additionally, spraying or fogging the banks of a river will not achieve control. Rather, it is best to focus on preventing the bites of these aggravating gnats.
Fishermen, hikers, or campers will be better served wearing protective clothing and covering any exposed skin. Buffalo gnats tend to bite up high on the head, face, neck, and arms. Consider wearing a hat with protective netting, which prevents the black flies from accessing these areas. Some studies have shown that black flies are more attracted to dark colored clothing than light colored clothing. Buffalo gnats are most active at dawn and dusk; avoid these peak activity times if possible. If you have electricity, arrange fans to have a steady breeze blowing through your riverside retreat area. As the weather cools, you will naturally notice a decline in the black fly population. If you are particularly sensitive to black fly bites, time your camping and fishing trips during times of the year when these biting gnats are less plentiful.
Sand Fly Gnats
True sand flies, of the family Phlebotomus, are not particularly problematic in the United States; in fact, when we use the term sandfly we are likely referring to biting midges (no-see-ums) or horse flies. However, in other parts of the world, the true sandfly is a biting menace and a vector of very serious diseases. True sandflies are about the size of biting midges or no-see-ums and have a hump-backed appearance. Sandflies are responsible for the spread of Chandipura Virus, which is a cousin of rabies. Sandflies also spread the bacteria that causes Carrion’s Disease and Leishmaniasis.
With bases and operations worldwide, our US Military personnel have experienced the dreadful diseases spread by the sand flies. Thousands of our soldiers who have served in the Middle East and South America have been diagnosed with Leishmaniasis. Leishmaniasis is a parasite that is spread through the bite of the female sandfly. This disease may present as skin ulcers on the body and eventually ulcers around the mouth and nose. Often, patients experience fever, low red and white blood cell count, and enlarged spleen and liver. The incubation period is long, it may be months or even a year before symptoms begin. Therefore, a service member may be home from deployment before the symptomatic boils begin to appear. A report published by Walter Reed Medical Center states that they diagnosed and treated 2,040 cases of Leishmaniasis between 2001-2016, with the majority of the cases linked back to a deployment to the Middle East. However, they suggest the number of affected service members is much higher as mild cases often go unreported or the diagnosis was made outside of the military medical system.
Worldwide, true sandflies are more than a pesky annoyance; they are a purveyor of deadly diseases. In areas where DDT was commonly used to prevent mosquitos and their diseases, sandflies were dramatically reduced. However, innovative, and novel approaches to sandfly management are required to prevent outbreaks of the above-mentioned dreadful diseases.
Non-Biting Gnats
In addition to biting gnats, humans and animals alike are afflicted with gnats that do not bite; it seems like these non-biting gnats exist only to annoy and pester. A few of these species can breed and reproduce indoors which can escalate into serious infestations if not properly treated. The most common non-biting gnats that disturb humans are eye gnats, fungus gnats, and sewer gnats. Although they don’t pinch, bite, or suck our blood, non-biting gnats can be exasperatingly irritating.
Eye Gnats
Eye gnats aggregate in large groups and the females feed on fluids in the eyes, nose, and any open wounds on the body. Because of their propensity to concentrate around the eyes and face, they are most often called eye gnats, but sometimes they are referred to as frit flies, grass flies, or eye flies. Although they do not bite, they are extremely annoying for people and animals alike. Eye gnats are known to spread conjunctivitis, or pink eye, among humans, and several diseases among cattle.
Individually, eye gnats are very small, approximately 1.5 to 2 mm in length, but when confronted with large groupings of these small gnats, they can be extremely irritating. Unlike many other pest gnats, eye gnats do not puncture our skin and take blood. Rather, they aggressively and persistently attempt to access human and animal secretions in the form of sweat, puss, eye sludge, and blood if available. They have spongy mouthparts that can absorb these secretions, which they require to produce viable eggs.
Eye gnats breed and develop in moist, sandy soil with abundant organic matter. Cattle fields, barns, and horse arenas are ideal breeding locations for eye gnats. They are not strong fliers, but they are often found miles from their breeding location because they are carried off by the wind. After a heavy rain, you may notice an increase in the population as well.
It is difficult to control or minimize eye gnats using pesticides alone. Particularly in agricultural areas, eye gnat control requires good cultural farming practices and efficient procedures related to the disposal of manure and other organic matter. Eye gnats lay their eggs in highly organic soil, and the young larvae (maggots) burrow into the soil and begin to eat organic matter and roots. Often, pest control applications do not reach the larvae under the soil and are thus ineffective. Mosquito repellents with DEET have been shown to prevent eye gnats from approaching people, but if you plan on applying an insecticide to an animal, read and follow the label closely. In addition, trapping eye gnats with homemade traps baited with raw eggs can help to provide some temporary relief. Eye gnats, which spend most of their time in the soil’s organic material, then gravitate towards our eyes, nose, and mouth, spread disease and are extremely irritating to both humans and animals.
Fungus Gnats
While some people have the knack and have grown lush indoor ecosystems, others have dried sticks sitting in a pot in the corner of the room. Wherever you fall on this green thumb spectrum, the challenge is to set up a watering schedule that allows the plants to thrive but not water so often that fungus gnats thrive. To verify which plant is infested with fungus gnats, place cheesecloth over the soil and let it sit overnight. The next day, check to see if the cheese cloth captured any fungus gnats. The best remedy for fungus gnats is to allow the soil to completely dry out before watering again. Once the soil is dry, the fungus gnat larvae will die. Adjust your watering schedule until you find the correct frequency that addresses the fungus gnat concern. An application of Bacillus thuringiensis (BT) can help kill off the fungus gnats. BT is a bacteria that is naturally occurring in soil and is toxic to fungus gnat larvae.
Sewer Gnats
Sewer gnats are another non-biting gnat that you may encounter in your home. Sewer gnats, of the family Psychodidae, are often called drain flies, filter flies, moth flies, sewer flies, or sink flies. As these terms imply, sewer gnats live and breed in sinks, drains, and sewers. Sewer gnat larvae live in the sludge-like slime of drains and the pipes around sinks, showers, and toilets.
Adult sewer gnats, or drain flies, do not look like a typical gnat. Most creatures that are sometimes referred to as gnats are small, black, bothersome flies that often accumulate in large clouds. Adult sewer gnats, AKA drain flies, have a decidedly moth-like appearance. Adult drain flies are about 1/5” in length and densely covered with hair. When at rest, they hold their wings over their body, reminiscent of a moth. Drain flies or sewer gnats can reproduce indoors, do not bite humans or damage your home, but they can become quite the eyesore.
The most effective way to get rid of these non-biting sewer gnats is to manually clean the drain, toilet, or pipe in which they are breeding. By removing the slimy sludge, which is rotting organic matter, you remove the food source for the nursery of larvae. Using a stiff wire brush, thoroughly scrub the infested area. Boiling water down the line may help to kill the larvae, but often doesn’t make contact with the sides and top of pipes. This leaves many breeding sites untouched. Regular maintenance of drains with a bacterial drain cleaner can help to prevent the buildup of organic material in which these flies breed. These products contain live enzymes that consume the sludge, thereby preventing the drain from being used as a sewer gnat breeding spot. Pest management professionals often apply these products as a foam that coats the entire surface inside drains and pipes for better results.
Gnat Bite Allergy
Of the biting gnats discussed above, here in the United States we are most likely to encounter biting midges (no-see-ums) or the black fly (buffalo gnat). These gnat bites are much like mosquito bites. Some people may be able to ramble through no-see-um-infested marshes without a single bite mark, while others will experience a rash, intense itchiness and discomfort, and redness for weeks after the romp in the woods.
The severity of the reaction depends upon how many bites you sustained and whether your body has an allergy to the proteins injected into your system from these bites. Depending upon the severity of your gnat allergy, the itch and discomfort may last up to a week. As is relatively common with bee and wasp stings, a reaction involving the inability to breathe is extremely rare after an attack of gnats. However, a severe allergic reaction after gnat bites is always possible.
Diseases Spread by Gnat Bites
In the United States, gnat bites rarely cause diseases or illness. However, in many other parts of the world, gnat bites exact a devastating toll on human health and life.
Biting midges, or no-see-ums, are extremely irritating to people but are not known to transmit any disease to humans. However, they can infect ruminants, mainly sheep, with the Blue Tongue Virus. This disease is not transmissible to humans but has a 30% mortality rate for young lambs.
Black flies, also called buffalo flies, are not known to spread diseases in the United States. However, they do transmit Onchocerciasis, also known as River Blindness, in Africa and other tropical areas of the world. River blindness is caused when the black fly bites and transmits a parasitic worm into a person. If untreated, onchocerciasis can lead to long-term skin damage and blindness.
Diseases spread by sandflies are not commonly found in the United States. However, in areas of Europe, Africa, South America, and the Middle East, these biting flies cause much human suffering. Sandflies can transmit the Leishmania parasite to humans. This parasite can cause cutaneous leishmaniasis, which is characterized by skin lumps or bumps that become scabbed over ulcers. Eventually, these ulcers become brightly colored boils. Sometimes, the parasite attacks the mucous membranes of the nose, throat, and mouth. The most serious leishmaniasis is when the parasite attacks the internal organs, known as visceral leishmaniasis. Often, the boils associated with this dreadful disease take months or years to clear, but without treatment, the visceral, or internal, form of this disease is often fatal.
While not a biting gnat, eye gnats are associated with the spread of conjunctivitis or pink eye. Eye gnats are not host specific, meaning they will feed on the eye fluid from a cow, a human, a pig, then a human again. Each time the eye gnat lands on or feeds upon a creature, it may encounter a bacteria or a virus. When the gnat subsequently feeds upon your eye, it may spread that bacteria or virus to your eye, causing pink eye. Eye gnats are also implicated in other terrible diseases throughout the world. In South America, eye gnats are believed to transmit yaws. Yaws is a skin disease that causes ulcers and, in extreme cases, can affect bone and cartilage. In Brazil, eye gnats are associated with spreading a particular bacterium that causes Brazilian Purpuric Fever, which may lead to sepsis in children.
Here in the United States, we are beyond blessed to consider gnats as simply a source of irritation rather than danger. The next time you are swatting away at the no-see-ums or the buffalo gnats, remember, unlike many places on Earth, these gnats are not likely to cause any long-term illness.
Gnat Bites on Dogs
If you like to take your dog with you on hiking or camping trips, be aware that they are susceptible to gnat bites as well. A campsite near the riverbank or the intercoastal waterway, although picturesque, invites biting gnats to the party. If you are getting bitten by punkies or buffalo gnats, chances are your pup is as well. You will undoubtedly notice your dog jump, scratch, and bite at himself to get the offending gnats off. Take simple precautions to protect your dog. If you have a fan set up to blow the gnats away, make sure your dog stays with you in the safe zone. Put your dog in the tent or camper if he is being terrorized by biting gnats. Talk to your veterinarian about dog-safe mosquito and gnat repellent. The bumps and rashes from gnat bites can become infected if your dog overly scratches them.
Gnat Bites Vs. Flea Bites
Gnat bites and flea bites may appear quite similar to each other. Both gnat and flea bites appear on your body as small, red, raised bumps. They both itch and their bites are usually felt at once. If you are experiencing fleas rather than gnats, there is more that can be done to eradicate the little biters. One way to differentiate them is the simple knowledge that fleas do not fly; they do not have wings. They have impressive jumping abilities, but if the insect that is biting you is visibly flying, it is not a flea. Also, be aware of your location when you are suffering the biting attack. If you are only attacked in gnat breeding zones, such as near the riverbank or saltwater marsh, biting gnats are likely to blame. Outdoors, fleas are usually found in tall grass, in the shade near trees and shrubs. If established on your pet, fleas may breed indoors as well, in carpeting, pet bedding, and furniture. A single gnat may slip in occasionally through a window, but they can not breed indoors like fleas can.
Of course, if you can capture a specimen of the biting insect, that is the best evidence of what is biting you. Absent a specimen, look at all of the circumstances surrounding your bite and follow the evidence to the biting insect. If fleas are to blame for your bites, fleas can be controlled with pet medications, yard treatments, and removing the fleas and eggs from your home.
Gnat Bites Vs. Bed Bug Bites
It can be tricky to differentiate bed bug bites and the bite marks of biting gnats from one another visually. Biting gnats hit hard and fast. They quickly pierce the skin, take your blood, and they are off. Bed bugs take minutes to fully engorge during a feeding. Because of this, they inject a numbing agent into your skin, which allows you to sleep through the bed bug bite. Biting gnats have no such analgesic, and their bite immediately causes pain.
Visually, bed bug and gnat bites may appear similar, however, the physical reaction to these insect bites is different for every person. Both of these insects may leave red itchy welts accompanied by swelling.
How To Treat Gnat Bites
For minor skin irritation and itchiness after a gnat attack, treatment usually consists of home-based first-aid-type remedies. Generally, the irritation and redness subside within a few days of a gnat bite. To prevent infection, avoid scratching the gnat bites and breaking the skin. If the bites are intensely bothersome, follow the guidelines below to alleviate the itch.
- Wash the affected area with soap and water.
- Apply a cold compress to relieve itch and reduce swelling.
- Apply over-the-counter itch creams such as hydrocortisone cream or calamine lotion to the bites. These salves will help soothe the irritation and redness caused by the gnat bites.
- An antihistamine medication, usually taken for allergies, may help to alleviate the gnat bite symptoms.
If your gnat bites are not resolving, or the affected area has pus or red streaks through the wounds, you should seek medical treatment. Skin infections are a common side effect of itchy bug bites, and with antibiotic-resistant strains of bacteria now, these infections can snowball into dangerous medical scenarios.
Although quite rare with regards to gnat bites, any allergen that you are exposed to may trigger a severe or anaphylactic reaction. If after being bitten by gnats, you experience difficulty breathing, swallowing, or swelling of the lips or mouth, seek immediate medical attention. This type of allergic reaction requires immediate medical care and should not be overlooked.
How To Prevent Gnat Bites
As a pest control company, there is little we can do to prevent gnat bites. Because most biting gnats live, breed, and bite near the water, most pesticides can not be legally used in these areas. However, your knowledge of their biology and behaviors gives you the power to prevent gnat bites. Those most commonly plagued by biting gnats are those who enjoy the great outdoors and are willing to brave the elements for the peace and serenity that they crave. As part of your outdoors checklist, make sure you factor in protection from no-see-ums and buffalo gnats.
If you plan on spending time in or around bodies of water, know that biting gnats are a possibility. Wear protective clothing that covers as much skin as possible. An insect repellent containing DEET or lemon eucalyptus oil has been shown to repel biting gnats. Many biting gnats breed in the moist muck along the edges of rivers, lakes, and marshes. Wear closed-toed shoes and socks when walking through this no-see-um nursery. As most gnats are poor fliers, a strategically placed fan may blow them off course and provide you some relief from these biting gnats.
At the end of the day, gnats are an annoyance and can cause seriously itchy bites, but in the United States, they rarely cause serious illness or injury. When you feel the pull towards nature as described by renowned naturalist John Muir, “the mountains are calling and I must go,” be sure to bring your biting gnat repellent gear!
Conclusion
Gnats, whether biting or non-biting, can significantly disrupt outdoor activities and negatively impact your comfort and health. Gnat bites can be particularly irritating, causing redness, itching, and discomfort. Understanding their biology, habitats, and behaviors is crucial for preventing painful bites and potential allergic reactions. While preventive measures and home remedies can offer temporary relief, lasting protection from gnat infestations often requires professional intervention.
Don’t let gnat bites ruin your outdoor enjoyment or disrupt your peace of mind. If you’re struggling with a gnat infestation, contact Nextgen Pest Solutions today. Our experienced technicians can provide effective and targeted solutions to control gnat populations and help you reclaim your comfort. Call us now for a consultation and take the first step towards a gnat-free environment.
