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How to Get Rid of Gnats
The best way to get rid of gnats depends on exactly what you mean when you use the term gnat. Gnat is a descriptive term rather than a truly scientific term. Many people use the generic term gnat for any small fly that they don’t immediately recognize as a house fly or a mosquito. Many outdoor flies that people may refer to as gnats are rarely found indoors and tend to not be the source of pest control calls.
When most people refer to gnats, they are usually referring to fruit flies, drain flies, and phorid flies. These are the small flies that appear in and around the rotting apple on your countertop or can be seen flying in and out of the drains. These are the gnats that are most likely to generate concern… especially in a commercial kitchen or the break room of a business. These more common small fly species are the ones that we will focus on in this article generically termed as gnats.
Types of Gnats
As mentioned above, gnat is a colloquial term that is often used to generally describe a small pesky flying insect. True flies, of the order Diptera, have 2 wings. There are over 125,000 true flies identified and it is believed many more species of true flies are yet to be identified. With this diversity among flies, it is no doubt a catch-all term such as gnat has gained traction in the English language. In pest control terms, when a home or business-owner calls with a gnat complaint, the issue is almost always fungus gnats, drain flies, fruit flies, or phorid flies.
The small black flying gnats buzzing around your potted plant are more often than not fungus gnats. Fungus gnats are common in greenhouses and in landscapes. When a house plant is brought indoors to escape cold weather, it may be infested with fungus gnats. Fungus gnat adults are approximately 2.5 mm in length and resemble a small mosquito. They can be distinguished from the shore fly, another common greenhouse problem, by the fact that the fungus gnat’s antennae are longer than his head. While fungus gnats can fly, they are not very strong fliers. They will often be observed hopping around or running on the soil of the potted plant.
Fungus gnats are not harmful to people, they are more considered a nuisance and an aesthetic pest. Many office lobbies and restaurants welcome guests, customers, potential investors and employees, and collaborators into a thoughtfully designed lobby area. Often live plants are incorporated into the interior design to elicit a feeling of freshness, potential for growth, and general health and well-being. These positive vibes quickly evaporate if your guests are greeted by a hoard of buzzing fungus gnats. Fungus gnats in your office or business sends the wrong signal and may cost you that top-tiered employee you were working to recruit or a loyal returning customer. In business, it is difficult to quantify the effect that pest control issues have on your success, but first impressions matter.
Serious plant damage from fungus gnats usually only occurs in greenhouse situations. However, if a fungus gnat infestation is not controlled and eliminated, they can cause damage to your plants. Fungus gnats develop in 4 stages, egg, larvae, pupa, and finally adult. The adults, although unsightly, do not cause damage to the plant, it is the larvae that can cause damage. Fungus gnat larvae are cream colored worm like creatures, approximately ¼ of an inch, with a black head. In a potted plant with excessive fungus fly larvae, they can damage the plant’s roots and stunt its growth. Particularly at risk for damage or death are tender young seedlings.
Fungus gnats are attracted to moist soil with a high organic content. Many indoor plants suffer from lack of water, however fungus gnats thrive when there is too much moisture in the soil. Between waterings, allow the surface of the soil to completely dry. This will break the lifecycle of fungus gnats. Make sure the plant is in a pot that provides adequate drainage. Avoid repotting plants in incomplete or untreated compost as it likely contains fungus gnats. Fungus gnats can move from one potted plant to another. Avoid placing an infested plant near a plant who is not infested with fungus flies.
A fungus fly infestation is pretty easy to diagnose. Often you will see the adults, which look like small mosquitoes, hopping or resting on the leaves, soil, or near the windows drawn to the lights. You can also set up yellow sticky glue traps. The trapping and removal of the adults lessons the immediate urgency but will not completely solve the fungus gnat issue. To determine the breadth of the infestation check for gnat fly larvae. Fungus gnat larvae are irresistibly drawn to wedges of potatoes. By placing wedges of potato into the soil, if the larvae are in the soil, they will come to the wedge of potato. You can use this as a monitoring tool or as a sort of trap. By removing and replacing the potato wedge every day or two, you can reduce the amount of fungus gnat larvae in your plant. However, this is just a band-aid fix. The best longterm solution is to properly water the plants and allow the soil to dry between waterings.
Fungus gnats can be controlled quite well with beneficial nematodes, although this is rarely the first suggestion for your home or business’ potted plant. Nematodes target the larvae which effectively cuts off the life cycle. However, in a home or business environment, fungus gnats can generally be controlled with altering the habitat. With proper water management, ensuring good root health, and an application of pesticide if necessary, fungus gnats can be eliminated allowing the beauty of your house or lobby plants to shine through and make the statement you intended.
When people complain of gnats, they may actually be speaking of drain flies. Drain flies are also called sewer flies, sewer gnats, sink flies, or moth flies. Sometimes phorid flies and fruit flies are incorrectly called Drain flies because they can come out of a drain. We will discuss those separately below. Drain flies often breed in the fine slimy surface of standing water in seldom used drains, toilet tanks, drip pans under the refrigerator, and any other small bit of standing water. Drain flies do not bite, but do present an unsanitary appearance in your home or business. Drain flies also risk the spreading of pathogens and bacteria around your home or business. Drain flies are most commonly found resting on the walls of a bathroom with a seldom used sink, shower, or floor drain. Female drain flies lay their eggs on the side of drains in the slime that accumulates on the surface. Without this slimy organic environment, drain flies cannot reproduce.
Adult drain flies are typically 1/5” in length and they are a species of non-biting gnat. They have one set of fuzzy wings that give them a moth like appearance. Drain flies’ wings are covered with a scales, therefore when squashed or swatted, they seem to disappear into a fine dust cloud. Drain flies are not strong fliers, rather they make short hopping flights, and can most often be seen resting on walls or ceilings. Drain flies do not come into your house via the drain. Rather, they come from outside, attracted to the organic debris that has accumulated in a drain.
When battling drain flies, it is important to figure out exactly where the drain flies are breeding. Drain flies are typically found near drains that do not regularly have water run in them. In residential settings, drain flies are most often seen when you come home from an extended vacation or travel. In commercial facilities, such as restaurants, hotels, health care facilities, and schools, there are often floor drains that remain unused most of the time. These seldom used drains are most likely dry which allows the drain flies to easily exit the drain.
A simple way to determine in which drain the gnats are breeding is to create a simple trap. One simple trap is a clear plastic cup with a small amount of petroleum jelly or vegetable oil. Place this cup over the drain for a few days. If immature drain flies are developing in the drain, you will capture the adults as they emerge and try to fly away. Another simple home-made drain fly trap consists of placing either a strip of tape over the drain or an insect glue board. An insect glue board is a simple piece of cardboard with a strong adhesive on one side. Depending on the brand and model, they come in different shapes and sizes and can be modified to fit your situation. Whatever test trap you utilize, leave it for a few days at least. Variances in the breeding cycle may mean that the larvae emerging as adults may not coincide with a one-night test.
Once you know which drains the gnats are breeding in, you must deal with the root of the problem. A solid understanding of drain fly breeding grounds is necessary to completely eliminate these pests. The only way to get rid of drain flies for good is to eliminate their breeding sites. Drain flies have been known to lay eggs in sewage pipes and even wet manure, but most commonly drain flies breed in the slimy organic matter that accumulates around the creases and edges of drains. Particularly in restaurants and bars, the rotting and decaying particles of food and drink are flushed down the drains, both in the sink and the floor drains. In restaurants, the most common moth fly breeding sites are sink and floor drains, grease traps, mops and mop tubs, and evaporation pans beneath the appliances.
Like other gnats, drain flies develop through complete metamorphosis, meaning they complete egg, larvae, pupae, and adult stages. The drain fly can complete its life cycle in as few as eight days, but may take longer depending upon the conditions. The female moth fly, or drain fly, will only lay her eggs on nearly saturated organic matter. She prefers the slimy gelatinous film common to overlooked drains. Once the eggs have been laid, they generally hatch in about 48 hours and emerge as drain fly larvae. Drain fly larvae cannot be disposed of by running water down the drain. They have the unique ability to capture air bubbles and survive underwater for about a day. If the problematic drain is not located and cleaned, drain flies can reproduce rapidly and you run the risk of spreading disease, allergens from the decomposing gnats, and health department violations and citations. It is in your business’ best interest to hire competent and professional support to combat and prevent drain flies from infesting your business.
When a customer uses the term gnat, another possibility is they are infested with fruit flies. Fruit flies are often simply called kitchen gnats, and sometimes they are referred to as a vinegar fly. Wherever there is food, there may be fruit flies. Commercial kitchens, school cafeterias (and lockers!), hotel rooms, grocery stores, and of course your kitchen counter are all likely places for a fruit fly infestation. If a piece of fruit or vegetable is left on the counter, or in the back of the pantry or cabinet, as it rots it will without a doubt, attract fruit flies looking to lay their eggs. Any fresh fruit or vegetable that is left out in the open is subject to fruit fly infestation… onions, potatoes, tomatoes left on the counter to ripen, even the 4th of July watermelon could bring in the fruit flies.
Fruit fly adults are small, approximately 1/8” in length and oval shaped. Most have characteristic red eyes, but there are also Dark-eyed Fruit flies that do not have red eyes. The front of their bodies are tan colored while their abdomen is black with a grey underbelly. Like other flies, fruit flies develop through complete metamorphosis. Controlling fruit flies involves recognizing their behaviors and what draws them indoors. As with all fly species, eliminating the breeding sites is the best control for fruit flies.
Fruit fly infestations are not limited to a rotten potato or banana in the fruit basket. Especially in restaurants and other commercial kitchens fermenting fruit and vegetable materials can be swept into cracks and crevices and rot into prime fruit fly breeding grounds. When dealing with a fruit fly infestation a thorough inspection is necessary so that all of the breeding sites can be eliminated. After the inspection, a thorough cleaning of the cracks and crevices of the kitchen is often deemed necessary as well. Fruit flies are attracted to fermenting fruit and vegetable matter. Food prep areas of restaurants are packed with potential fruit fly breeding sites. If a piece of lettuce, tomato, or lemon slice, drops to the floor and is inadvertently swept under a prep table, the clock starts to count down before fruit flies find it and begin to reproduce.
In restaurants and bars, fruit flies are often found breeding in obscure difficult to find locations. Most restaurants manage to clear the prep tables and surfaces of large bits of food, but within the intricate appliances and hardware of a commercial kitchen there are many cracks and crevices. To the human eye, the area can appear pristine, but to a fruit fly a restaurant kitchen is a land of unbridled opportunity. Restaurant floors are often cleaned by hosing down the floor with a hose. The pressure from the water hose can force organic debris into cracks and crevices on the floor. As this process is regularly repeated, the organic matter accumulates in corners and around the base of table legs, storage shelfs, and appliances. Accumulation of fruit and vegetable matter wrapped around the legs of a prep table can support fruit flies. The gunk that drips out of a trash bag into the can is enough to support fruit flies. Spilled juice, bar mixers, and alcohol that accumulates under a blender or mixer is paradise for fruit flies. Loose tiles on the floor or backsplash can gather organic matter and harbor fruit fly eggs and larvae. Floor and sink drains, garbage disposals, and soda lines and drip pans are common areas for fruit flies to lay their eggs. In a small business environment, make sure someone is assigned trash and recycle duty. Empty soda bottles and apple cores left around will undoubtedly draw in the fruit flies. Until all the breeding sites are located and cleaned fruit flies will continue to plague your restaurant or office break room. The adults you see are less than 10% of the total population.
The reproductive capability of fruit flies is astounding. If given the opportunity, a female fruit fly will lay 500 eggs in her lifetime. The life cycle is comparatively short; if conditions are prime, fruit flies can develop from eggs to adult in approximately 1 week. Within a very short time, fruit flies can overwhelm a facility and cause damage to the reputation of the business.
In your home, fruit flies can often be handled by simply throwing away the rotting banana and wiping up the seepage from the rotting piece of fruit. However, in a commercial scenario, a thorough inspection and cleaning is required to wipe out fruit flies. A single insecticide spray, a water flush, or a quick wipe down with a bleach wipe will not solve this problem. Small and large appliances should be moved and cleaned underneath. The joints of every prep table should be thoroughly cleaned, including where the legs of the table meet the floor and where the tabletop is connected to the legs. If necessary, scrape out any grime that has accumulated. Create processes and procedures to ensure that every nook and cranny of your restaurant kitchen is thoroughly cleaned on a regular basis. Sufficient training and accountability should be in place to ensure the procedures are adhered to. Without obsessive attention to deep cleaning of a commercial kitchen space, fruit flies will find a way to reproduce.
Once the fruit fly infestation is cleared, regular and preventative maintenance of drains, soda machines, trash bins, and surfaces is necessary. Fruit flies are quick; they will find the breeding location before you even realize the accumulation of gunk is happening. Pest Management Professionals know these pests; we know where they hide and how to treat them. While you operate your business, it is often wise to have a knowledgeable and professional pest control company handle the pests in and around your restaurant. By regularly treating and maintaining the drains, and keeping all pests out of your kitchen, you can focus on providing the best experience for your customers.
Another small bothersome fly sometimes referred to generally as gnats are phorid flies. Phorid flies are also called sewer flies, coffin flies, and scuttle flies. Phorid flies are only about 0.5 mm in length and to the untrained eye closely resemble fruit flies. The phorid fly’s back side arches up, inspiring the nickname humpback fly. The adults are poor fliers and travel prefer to run across the surface rather than fly away when they are disturbed. This characteristic movement generated the nickname scuttle fly.
Rather than sticking to rotting fruits and vegetables favored by the fruit fly, phorid flies also will reproduce in ANY rotting liquidy organic matter. Their favorite foods also include decaying flesh and feces. While this may seem unlikely in a restaurant kitchen or hospital cafeteria, consider for a moment the amount of raw meat that is brought into these areas every day. If a bit of raw hamburger is caught in the crevices of the prep table and remains stuck for any period of time phorid flies will be drawn inside. To eliminate phorid flies, you must locate the breeding site and clean it of any organic matter. Phorid flies are common both in mausoleums, and in garbage disposals. Phorid flies are common in sewer pipes and sink and floor drains. They have been found breeding in mop buckets, and in that tight space where tables and large appliances meet the floor. Phorid flies will lay eggs in meat juice that has dripped from a garbage bag.
The phorid fly’s proclivity for crawling through and walking on dead and decaying matter tells us that their presence is a health and sanitary risk. Phorid flies are of special concern in hospitals and healthcare facilities, especially where open wounds and damaged flesh are treated. Phorid flies are not always a result of poor sanitary practices though. A surgery center had to close for weeks due to a phorid fly infestation. It was ultimately determined that an underground a pipe was broken which led to the dishwasher in the kitchen. A major repair of the plumbing system sealed nature out of the hospital and the phorid fly infestation was solved; although at great expense.
If the breeding ground is not located or is inaccessible, phorid flies can reproduce at astonishing speed. One female phorid fly can lay about 500 eggs in her lifetime. She lays these eggs on the rotting meat or other organic matter. When the eggs hatch, the larvae emerge and begin to feast upon the decaying matter into which they were born. The larval stage lasts between 1-2 weeks after which they crawl to a drier location and enter the pupal phase. If conditions are ideal, phorid flies may go from egg to adult in one week, however, they usually require 2-3 weeks to fully develop.
Phorid flies breed anywhere moist rotting material is present. Outdoors, in nature, phorid flies breed in sewage contaminated soil, dead animal carcasses, and trash. However, indoors the breeding grounds are much more difficult to locate. But, in order to get rid of these troublesome gnats, these locations must be tracked down and cleaned of the organic matter. Even a small area of grime, can support thousands of phorid fly larvae. It is not always accurate to assume that the breeding site is near where you observe the adult phorid fly. While they are not strong fliers, they tend to follow air currents and scatter about the location. They are also strongly attracted to lights. In an infested structure, phorid flies often have more than one area where they lay their eggs. Do not stop looking once you have located one phorid fly breeding site, there are likely more sites close by. Remember, that phorid fly larvae can only survive in moist conditions. In addition to the usual places such as garbage disposals and trash cans, carefully inspect plumbing and drains in both kitchens and bathrooms. Carefully inspect crawl spaces, wall voids near plumbing issues, and basements where moisture issues are known. Phorid fly breeding grounds can be notoriously complicated to locate.
Some of the most troublesome phorid fly infestations involve broken pipes under the ground. Sandy soil contaminated with leaky sewage is the perfect breeding media for phorid flies. They are very capable of crawling 3 feet or more through the soil and entering the building through cracks in the foundation. When this happens no amount of scrubbing underneath the stand mixture or the baseboards will get rid of the phorid fly invasion. The only way to stop the flow of filth breeding flies, such as phorid flies, is to repair the damaged pipe. This is often expensive and invasive. A business may have to close while the repair is underway, causing a substantial loss of revenue. If you suspect a broken pipe may be causing your phorid fly infestation, in addition to a Pest Management Professional, you will likely need the expertise of a plumber and a contractor.
Gnats vs. Flies – What is the Difference?
The differences between gnats and flies depends on exactly what you mean when you use the term gnat. The term gnat is often used for a small annoying flying creature. When trying to get rid of gnats from your home or business, it is always best to identify the problematic gnat down to the species. Treatment recommendations will be different if your “gnat” is a no-see-um (biting midge), a fruit fly, or a fungus gnat.
Not every insect that flies is a true fly. True flies are in the order Diptera and share the following characteristics:
One pair of wings (most insects have two pairs of wings).
Hindwings reduced to small club-like appendages called halteres, used for steering while in flight.
Piercing, sucking, or spongy mouth parts used for ingesting their meals in liquid form.
Mature through complete metamorphosis – egg, larvae, pupae, adult.
To further complicate matters, species with the word “gnat” in their commonly accepted name, such as eye gnats and fungus gnats are actually very small true flies. As you can guess, the common house fly is a true fly, but so is a mosquito. No-see-ums, which are the tiny “gnats” found near marshy areas and notorious for their vicious bite, are technically true flies as well. The “gnats” that are swarming near the kitchen sink and the rotting bananas on the counter are true flies as well.
This discussion of true flies further begs the question, what is an example of a flying insect that is not a true fly? Many species of beetles fly, yet they are not a “true fly.” Beetles are in the order Coleoptera, meaning their front wings are hardened into a hardened wing case like a shield. Lady bugs, flour beetles, and cigarette beetles can all fly, but they are beetles. Despite their name, fireflies are not a true fly, they are also beetles. Another example of flying insects that are not true flies are winged termites and ants. Not all termites and ants have wings and the ability to fly, but the reproductives, or alates, do have the ability to fly. Some species of roaches have wings and the ability to fly, but are not true flies.
The diversity present amongst insects is awe-inspiring. Because common names often do not truly and accurately represent the insect’s characteristics, it is very easy to confuse insects. Gnat, in particular, is a difficult term because there is no scientifically accepted definition. Luckily, your knowledgeable Pest Management Professional at Nextgen Pest Solution can accurately identify the fly and provide treatments and solutions that get rid of the flies and prevent them from coming back.
What are Gnats Attracted to?
The small black gnats buzzing around your kitchen or bathroom are attracted to rotting organic material. Organic is not being used in a wholesome and pure way here. Organic material, or organic matter, is anything that comes from a recently living organism. Apple peels, rotting potatoes, and meat and/or fruit juices that have dripped from the trash bag into the can are organic material. Just as the rotting animal carcass in the attic is considered organic material, the meatball that rolled off the counter and under the table is also considered organic material.
However, the organic material that fruit flies, drain flies, and phorid flies use as breeding grounds are rarely as obvious as a carcass or a raw meatball. These small flies, often generally referred to as gnats, are attracted to the organic matter that is not so readily apparent. Specifically in commercial kitchens, the floors should be cleaned nightly with either a mop and bucket or by hosing the floor free of grease and debris. This cleaning procedure tends to push tiny particles of organic matter into hard to reach and hard to clean areas. Organic grime or sludge begins to accumulate in corners or uneven areas on the floor. Organic matter accumulates in the places where the tables and appliances meet the floor. The floor and sink drains often have layers of goo and grime. These areas stay moist because of the nightly cleaning. Unless these areas are cleaned by hand on a regular basis, they will become prime breeding grounds for gnats of all kinds, phorid flies, drain flies, and fruit flies.
One of the more common “gnats” found in the kitchen is the fruit fly. The fruit fly is strongly attracted to the smell of fermenting fruit. A beginning stage fruit fly infestation will make itself known when you open a bottle of wine. Have you ever walked away from a glass of wine, only to come back a few hours later to find gnats, or fruit flies, floating on the surface? New research indicates that fruit flies use both their strong sense of smell, but also their eyes to locate the rotting or fermenting material. Fruit flies not only breed on fruit and vegetables, but they can breed in beer bottles, mops and cleaning rags, and garbage disposals. Due to their specific attraction to fermenting materials, fruit flies are often called vinegar flies. Vinegar traps are also a common way of initially reducing fruit populations.
Where do Gnats Come From?
You’ve been watching that banana for a few days now, fully meaning to put it in a smoothie or turn it into banana bread. You make a mental note to pick up some sugar when your out today… one more day won’t hurt. When you get home, small black gnats are buzzing around your entire fruit basket, originating from the over ripe banana. Where did these gnats come from? It’s as if they miraculously appeared.
Many people refer to any small bothersome flying insect as gnats. The “gnats” in the above banana scenario or probably fruit flies. Fruit flies, phorid flies, drain flies, and fungus gnats are the small flies that most commonly invade homes and restaurants. Almost all species of flies have an excellent sense of smell. They are drawn to the odor of rotting and decaying fruit, vegetables, meat, or other natural material such as fecal matter. It is believed that the common house fly can detect odors from up to 4 miles away and blow flies can smell a dead carcass from up to 10 miles away.
Most commonly these flies enter our homes and restaurants when they identify the odors in which they can lay their eggs. They instinctively know that when their eggs hatch and the larvae emerge, the larvae will need to eat. These filth-breeding flies, ensure their survival by placing their eggs directly onto the larval food source. These small flies usually get indoors via small cracks under the doors and around windows. Some small flies can fit through typical window screening providing easy access through your kitchen window.
Sometimes these pesky flies can be brought in from the grocery store. With the popularity of personal shoppers and pickup grocery orders, many people do not choose their own produce anymore. You get what is picked for you… even if the peaches at the store look old and terrible, your shopper will grab them and you will bring them into your house. Sometimes, a fly has already laid eggs on the produce either at the packing plant or at the grocery store. In this instance, the life cycle is already underway by the time you place the questionable peaches on your counter.
The other common place that these small gnat-like flies come from is from underground. Broken pipes under the concrete slab of your home or business cause the most problematic fly infestations. Phorid flies can breed in enormous numbers in this shadowy environment. A sewage or septic line can break due to the settling of the structure or invading tree roots. When this happens large amount of sewage (organic matter) can accumulate under the slab of the structure. Flies, and other pests such as roaches, breed in this sludge, and ultimately are attracted to the light of your home. If they access your home, flies by the thousands will enter. A licensed plumber can perform a smoke test or inspect with video equipment to look for this possibility.
Life Cycle of Gnats
The gnats that circle the drains and hover over the fruit basket are technically flies. Gnat is a generic term for these small pesky flies that invade our homes and businesses. To understand how to get rid of these pests, it is first important to understand their life cycle. An understanding of how and where they breed is fundamental to controlling these pests both in a residential and a commercial setting. When a customer refers to gnats, they are usually referring to fruit flies, drain flies, phorid flies, or fungus gnats. Each of these species of flies has the capacity for exponential reproduction if the life cycle is not interrupted. The only effective way to get rid of gnats for good is to eliminate the breeding sites.
These flies mature through the process of complete metamorphosis. The time it takes to progress through the stages depends upon the species of fly, the weather and temperature conditions, and the quality and availability of food. In optimum conditions fruit flies, phorid flies, and drain flies can progress from egg to adult in one week. Generations of flies can coexist. If a breeding site is left to fester, it can sustain eggs and larvae, and the pupae are generally not far away. Meanwhile, adults will be flying around and return to the breeding site to lay more eggs. This rapid life cycle guarantees a fly infestation can quickly turn into a big problem. Female flies purposefully choose locations with rotting or decaying meat or vegetation to lay her eggs. Once the eggs hatch, the larva emerge. Each species of fly larvae looks slightly different, but they are generally small, white or cream colored, legless, worm-like creatures. These maggots wriggle about and eat the rotting organic matter into which they hatched. Often the organic matter is less obvious than a large rotting potato or tomato. You may not smell it or immediately see it. Wherever this breeding site is located, moisture is almost always present. Some fly species can develop in water. Drain fly larvae develop and thrive in the gelatinous surface film inside sink drains. Even a small amount of gunk, slime, or sludge can sustain generations of filth breeding flies. Small gnats will never go away until you locate this breeding location and eliminate it.
Once the larvae/maggots have had their fill, they usually squirm just out of the goo and prepare to pupate. The pupal phase is similar to a butterfly in a cocoon. During the pupal phase, the developing fly is protected by a hard shell casing. Depending on the species and surrounding conditions, the pupal phase may last a few days to about a week. Once the legs and wings have developed the fly emerges from the pupal casing and the process begins anew.
Preventing a Gnat Infestation
Prevention and active monitoring is key to controlling small flies commonly referred to as gnats. Fruit flies, phorid flies, drain flies, and fungus gnats are all considered filth breeding flies. The best prevention for filth breeding flies is to eliminate the waste in which they lay their eggs and where the larvae develop. Sanitation is key.
Clean and remove any rotten or old food.
Wipe up spills quickly and thoroughly.
Create a schedule for cleaning under large appliances and equipment.
Inspect and clean around the feet of prep tables and other equipment.
Take out the trash nightly and clean the trash bins regularly.
Hang mops so that they dry thoroughly.
Clean under mats in kitchens and bathrooms.
Repair broken tiles as these gaps can harbor organic debris.
If the source of your gnat issue was a dirty sink or floor drain, consider using an enzyme based drain treatment to keep it clean. By preventing the slime from accumulating in the threads and grooves and turns of the pipes and fittings, flies will have no place to develop and mature. A high quality enzyme drain cleaner is often a vital step to keeping your home or business free of flying gnats. These products come in various formulations, thick viscous gel that coats the drain, foam in an aerosol can, and a liquid cleaner that can be added to mop water. These products contain live microbes and enzymes that eat the organic debris. These products usually have a pleasant citrus smell, and when used regularly, prevents grease and grime from accumulating. These all-natural microbial products are labeled for use in food prep areas, drains, dumpsters, kennels, and urinals. This versatile product is easy to apply wherever odor and organic sludge is a problem.
Once the hard work of eliminating the gnats and flies is complete, preventing them from coming back is an ongoing effort. It requires constant vigilance and upkeep to prevent these flies from returning. Monitoring for gnats is a worthwhile endeavor and will help you catch an infestation in its early stage. A simple fly light with glue boards will tell you if gnats are buzzing around your kitchen again. If you notice an uptick in captured flies on the glue board, clean the drains and toss the rotten banana.
If you have identified your pesky species as a fungus gnat, prevention may require a change to your potted plant procedure. Fungus gnats are almost always found in and around the soil. When plants are brought indoors in a big pot of nutrient rich soil, fungus gnats may be attracted to that plant. Now, I’ve never been one to over-water my plants, my problem is quite the opposite, however, to prevent fungus gnats allow the soil to fully dry before watering again. Remember that flies need moisture to complete their live cycle, so allowing the soil to dry out prevents fungus gnats from completing their life cycle. Fungus gnats lay their eggs in the first inch of soil. By placing gravel or small pebbles on top of the soil, your potted plant is less attractive to fungus gnats looking to lay eggs. In general, by improving the drainage of your potted plants, you can prevent a fungus gnat infestation.
Gnats in Restaurant Kitchen
Commercial kitchens have a vested interested in keeping small flies and gnats of all species away. Phorid flies or fruit flies infesting a restaurant can be the basis for failing a health inspection, bacteria spreading in your kitchen, or a negative customer experience. In the restaurant business, you have to excel and impress on all fronts. If the food is crave worthy, the service is spectacular, and the atmosphere is fun and engaging, if small phorid flies are buzzing around your customers’ faces, you will be saddled with a negative review. Your only option is to get these kitchen gnats under control and maintain protocols to prevent them from coming back.
You can not spray your way out a small fly infestation. The only way to get rid of these small gnats is to eliminate their breeding sites. With so many nooks and crannies in a commercial kitchen, the breeding site possibilities are plentiful. A well-trained Pest Management Professional has a keen eye for finding these locations. Floor and sink drains are often problematic. Every commercial kitchen is unique, depending upon the equipment and storage needs required to operate your business. Often the areas that these gnats are breeding in escape the untrained eye, but moisture is a prerequisite. Enzyme based products help to eliminate the grime that accumulates, and should be used as part of the regular cleaning procedure, but there is no substitute for good old fashioned elbow grease. Sanitizing a commercial kitchen to remove the fly breeding sites is an extensive endeavor; once it is accomplished, it is much easier to retain best practices. Often commercial kitchens require control and prevention of roaches, ants, rats and mice, and flies. Sanitation is key to controlling and preventing all of these potential issues within a restaurant kitchen.
Keep doors closed as much as possible and install air curtains to prevent insects from entering while you accept deliveries.
Resist the urge to prop open doors.
If you must open windows, ensure the screens are in perfect condition with holes small enough to keep out these tiny flies.
Gnats, flies, roaches, and rodents take up residence in your restaurant or cafeteria unless strong proactive measures are implemented. At times the rules and regulations on food storage and safety may seem onerous and overly aggressive, but by not cutting corners on these details, you reduce your risk of dealing with a small fly or gnat infestation.
Gnats in My House
When small flies or gnats invade your home, you must locate the breeding site, clean it, and ensure it stays clean. It could be as simple as fruit flies laying eggs in the rotting peaches that are in your fruit basket. The problem could be that phorid fly larvae are thriving in the drip pan under the refrigerator. Drains should be free flowing and clean of organic grime and gunk. Whether you are battling, phorid flies, drain flies, or fruit flies, the truth remains, eliminate the breeding location, you eliminate the gnat.
If you are unsure if small flies or gnats are breeding in your drains, you can perform a simple test. Place tape over a drain leaving a little room for air flow. When you check the tape in the morning, if flies are breeding in this drain, you will find some stuck on your tape. You will then know that this is a drain you need to thoroughly clean. Do not pour bleach or pesticide down the drain, it will not solve your problem. Using a stiff wire brush, scrape all of the organic grime out of the crevices of the drain. Once you have physically removed as much filth as you can, consider using an enzyme based cleaning product. These products contain live microbes that eliminate the organic matter that flies breed in by essentially eating it. These products often have pleasant citrus odors and come in a variety of formulations. The easiest for the homeowner to apply is a thick viscous gel. Simply pour it down the drain before bed. Repeat as necessary until the grime is gone. Many people proactively use these products on a regular schedule… just to avoid this problem again.
If you have large numbers of gnats in your home and have not found a breeding site, the source of the fly problem may be below your home. When a drain or sewer pipe breaks beneath the concrete slab, phorid flies will breed in the seepage and invade your home in enormous numbers. Diagnosing and solving this problem often involves the aid of a plumber and possibly a contractor.
Gnats in the Bathroom
Of the gnats that we have discussed in this article, drain flies are the ones that will most commonly be found in your bathroom. Drain flies, also called moth flies, lay they eggs in the organic matter that accumulates in the sink and shower drains in your bathroom. The larvae live in and feed upon this grime until they pupate then emerge as adults. As adults, drain flies look like fuzzy moths and will most likely be seen just sitting on the bathroom wall.
As with other flies, the same rule applies, you must locate the breeding site and clean it thoroughly. Verify the problem drain by placing a strip of tape over the drain, but don’t cover it completely. If the drain is indeed infested, you should find drain flies on the tape. Thoroughly clean the drain with a flexible drain brush. There are brushes designed precisely for this job. They have stiff bristles to clean the crevices and enough length to reach deep into the drain. This can be a time consuming and dirty job as you may need to disassemble all or some of the drain to clean all the grime. Follow up the manual cleaning with an application of enzyme gel drain cleaner. This gel cleaner does not use harsh corrosive chemicals, rather live microbes that eat the remaining grime in the drain. These products are safe for drains and pipes, smell great, and can be used regularly to prevent the accumulation of the gnat attracting slime.
Commercial Gnat Traps
Many restaurants, commercial kitchens, and residences choose to install commercial grade traps. These traps are useful tools when installed and maintained correctly. In commercial kitchens, it is generally not recommended to use zapper style fly traps, rather to use fly lights. Fly lights attract flies to the light, then utilize an adhesive glue or sticky card to capture the fly. It is important to note that fly lights alone will never solve a gnat or small fly problem. At best, they may capture a few adults and help to reduce the population a bit. By inspecting a fly light glue card, your pest control technician can identify the types of flies that are in your establishment and track the severity of the infestation. In a restaurant which needs a comprehensive pest control plan, fly lights are a necessary and helpful tool.
When determining whether to install commercial grade fly lights to combat gnats, there are a few things you should know. First, it is generally accepted that they are wholly ineffective against fruit flies. Fruit flies do not have a strong attraction to light and will therefore not be drawn to the trap. If you capture any fruit flies, it will be incidental. Your other main gnat or small fly of concern is phorid flies. Phorid flies are only mildly attracted to light, it by no means a strong attraction to light. If phorid flies are breeding in the area, you will capture them on your fly board and ideally treat the issue early in the infestation.
High quality commercial fly traps require an initial investment and require regular maintenance. Like all light bulbs, they dim over time and need to be changed. Also, the glue boards should be inspected and changed regularly. Commercial grade fly traps are an important facet of a comprehensive IPM or Integrated Pest Management program, but should not be relied upon to solve a fly or gnat problem on their own. If you decide to purchase fly lights for your restaurant or commercial kitchen, commit to maintaining them and inspecting them for the clues they contain.
Fly lights are available in many brands, sizes, and specializations. Some fly lights are disguised to look like light fixtures or sconces. These can be placed in the dining room and your guests will never know their intent. Some fly lights are safe to be placed in wash down areas, while some of the zapper models can be placed near receiving doors. Your Pest Management Professional can guide you in the selection and maintenance of fly lights in your commercial kitchen.
DIY Gnat Traps
Some species of small flies or gnats can be captured without an expensive and bulky fly light. Fruit flies are strongly attracted to the odor of anything fermenting. Nearly empty beer bottles or a wine glass with a sip or two left over, will quickly draw in the fruit flies. Of course, we can use this to our advantage as well. A fly trap should never be expected to eliminate a gnat infestation. However, utilizing a homemade gnat trap to reduce the number of adults can make life more tolerable while you do the hard work eliminating the breeding locations.
Fruit fly traps are readily available for purchase and they are effective in trapping some adults, however they are just as easy to make yourself. Simply pour vinegar, some people prefer to use apple cider vinegar, and a small amount of dish soap in a small bowl or Mason jar and cover. Poke holes in the top so that the gnats can find their way inside the trap. The fermented odor of the vinegar will draw them in and the dish soap prevents them from escaping.
Since phorid flies and drain flies do not have the same attraction to fermented substances as fruit flies, there are really no DIY traps that effectively draw in the adults of these species. Small homeowner versions of fly light traps will be more effective for trapping adult phorid flies in the home. However, any trap or device for gnats will only capture a portion of the adults. These gnats are prolific, and their life cycle will continue until you eliminate all of the breeding locations within your kitchen.
How to Get Rid of Gnats from a Commercial Kitchen
Whether your commercial kitchen consists of a restaurant, a cafeteria within a hospital or long term care facility, a bakery, or a food truck, small flies or gnats, present a formidable problem. Professional pest control has evolved over the years to focus on prevention and exclusion as opposed to liberally applying pesticides, especially indoors. While this frustrates some customers who want a spray it and forget it solution, this Integrated Pest Management approach yields better longer lasting results. Minimizing pesticide use is especially important in the food prep and storage areas of a commercial kitchen.
A small fly or gnat problem is always indicative of a sanitation issue. This is not to say your kitchen is filthy, these flies can breed in the tiniest bit of gunk and slime which is often tucked away outside of plain view. While each species has their preferred filth in which they lay eggs, all of these gnats require moist organic matter to complete their life cycle. A thorough inspection to locate the breeding site is the first step in controlling any of these species of filth breeding gnats. Inspect and clean under every small and large appliance, sinks and drains, trash cans, and kick plates. A small spill or area of neglect can produce an enormous problem, so be thorough in this inspection.
Once you find a breeding location, continue your inspection. Phorid flies in particular, often have more than one breeding location within a site. In commercial kitchens, the nature of the nightly cleaning routine actually encourages gnat reproduction. When water hoses are used to wash down the floors, the water pressure forces food debris and moisture into cracks, corners, and crevices. All of the floor and wall tiles and kick plates should be carefully inspected, scraped clean of organic debris, and repaired if necessary. The floor drains common in commercial kitchens are also notorious for proliferating gnat like flies. These should be disassembled if necessary, and thoroughly scrubbed and scraped clean. Anywhere you find gnat larvae swimming around in wet kitchen gunk, you must physically scrub the area clean, then formulate a plan to prevent this from happening again.
Pest Management Professionals have several tools available to prevent gnats or small flies from breeding in your commercial kitchen. Enzyme based cleaners are beneficial when used regularly. These products contain live microbes that eat the organic buildup that accumulates in the drains, cracks in the floor, and anywhere else that moisture and food debris collect. As part of your regular procedures, you should implement these products into your rotation. In various formulations, they can be added to mop water, poured down the drains, utilized in beverage systems. Using specialized equipment, your Pest Management Professional can create a foam that coats and cleans the sides and crevices of your drains. This thorough application ensures the cleansing microbes have access to all the gunk. While we never place traditional pesticides down the drain, some Insect Growth Regulators (IGRs) are labeled for use in drains. IGRs are products that do not necessarily kill breeding adult gnats, but they can prevent immature gnats from fully maturing and becoming capable of reproduction. This disruption in the life cycle is invaluable when combatting gnats in a commercial kitchen. These products are most effective when converted to a foam and applied directly to the problem drains and other cracks and crevices.
The conditions that allow gnats to proliferate in a commercial kitchen also breeds roaches, ants, large flies, and possibly rodents. Any restaurant is at risk for pests in the kitchen and should invest in regular professional pest control service. Fly lights are always recommended for commercial kitchens. They not only help to catch an occasional fly that makes it past all other barriers, but they can act as a canary in the coal mine. While fruit flies are not attracted to these fly lights, phorid flies can be. By regularly maintaining and checking the glue boards, you will know if a specific pest is increasing. With this knowledge, specialized treatment can begin before the infestation is severe.
Your commercial kitchen is unique. Nextgen Pest Solutions can design and implement a program that treats and prevents not only gnats, but roaches, ants, rodents, and large flies. In a commercial kitchen, all of these pests and their control is intertwined. Getting rid of these pests is our specialty, let us take care of them so you can focus on serving up delicious plates.