How to Get Rid of Flies – An Integrated Pest Management Approach

There are more than 110,000 species of flies in the world. Flies are divided into a few categories as treatments and control can vary. There are large flies, small flies, biting flies, and non-biting flies. Many flies breed in organic debris such as feces, rotting carcasses, food or garden waste, and garbage. Flies are known transmitters of disease, such as E.coli, shingellosis, typhoid fever, and cholera. Flies are known to have high resistance levels to traditional insecticides, therefore the most effective method of fly control, is to eliminate the breeding source. In this article, we will focus on the flies that most commonly occur in and around the home.

Flies are more than a nuisance; they are known to transmit disease and should be controlled in and around your home. The principles of Integrated Pest Management (IPM) provide guidance on safely and effectively solving your pest problem while reducing the use and exposure to pesticides. IPM principles teach us to solve pest problems at the source or prevent them altogether. This not only makes for a truly pest free home but is environmentally friendly as well. In this guide we will outline principles and procedures that you can put into place in your own home or business, to help you solve your fly problem.

Where Do Flies Come From?

To truly solve a fly problem, you must determine the breeding site and destroy the fly habitat. You will not get adequate fly control by focusing on adult flies alone. At a given time, adult flies are only about 10% of the population, meaning flies can reproduce faster than you can kill the adults buzzing around. Flies that breed in garbage and or feces are generally referred to as “filth flies.” Other flies may breed in decaying vegetable matter such as grass clippings. The common house fly is one of the most common flies that infest dumpsters, manure, and other food waste.

Commercial and residential concerns are vastly different with regards to flies. A restaurant or dairy farm will have different protocols and procedures for fly control from a residential home in a typical suburban neighborhood. In commercial applications, common causes of flies in buildings are dumpsters too close to the buildings, doors propped open, and lack of drain sanitation. A homeowner, however, can typically make immediate improvement in the fly situation by picking up their dog’s fecal matter.

The short answer as to where flies come from is an unsanitary condition somewhere close by. Effective fly control depends upon locating and eliminating the fly breeding site. If the breeding site cannot be eliminated, such as in livestock barns, protocols should be put into place to disrupt the fly life cycle to reduce the number of flies. Filth flies have an enormous reproductive potential if breeding sites are not eliminated. House flies for example, can have a lifecycle of only 6 to 10 days long and each female can lay up to 900 eggs in her lifetime.

Fly Identification – Large Flies

Each fly described below has unique characteristics, biology, food preferences, and control methods. Therefore, proper identification is crucial in understanding how to best control your fly problem. While the presence of one type of fly may indicate a garbage dweller, another type of fly may indicate the presence of a dead animal in your attic or wall void. Below are general guidelines for common large flies. Of these large flies, the house fly is the most common fly pest for homeowners. Your local extension office is a valuable resource to help you to positively identify your fly specimen.

House Fly

• Species: Musca domestica Linnaeus
• Size: 5/16 inch long
• Color: Thorax is gray, with four longitudinal dark lines on the back
• Behavior: only active during the day, good fliers, rest on corners and edges
• Breeding sites: Garbage
• Lifecycle: 6-10 days
• Key characteristics:
  • Larvae (maggots) ½ inch long, white, worm-like, tapering body
  • Pupae are reddish brown, 3/8 inch long and similar to puffed rice in shape and size.
  • Wings of adult have an “elbowed vein”
• Impact: annoyance, transmits disease causing pathogens

Little House Fly

• Species: Fannia canicularis Linnaeus
• Size: 3/16 inch long
• Color: Looks like house fly with three brown stripes on abdomen
• Behavior: Adults have hovering jerky flight, males hover in shaded areas like doorways
• Breeding sites: Garbage and manure (particularly chicken manure)
• Lifecycle: 15-30 days
• Key characteristics: Larvae and pupae are brown flattened and spiny
• Impact: Annoyance, transmits disease causing pathogens, larvae known to occasionally develop in intestines of human beings and other animals (intestinal myiasis)

Flesh Fly

• Species: Multiple species in the family Sarcophaga
• Size: 1/2 inch
• Color: Gray
• Behavior: Not usually found indoors, unless associated with a carcass. Larvae sometimes feed on larvae of little house fly and blow fly.
• Breeding sites: Decaying meat, fish, and garbage
• Lifecycle: 13-18 days
• Key characteristics: Three stripes in thorax, abdomen has checkerboard pattern, on many species the tip of the abdomen is red.
• Impact: Little impact on humans, occasionally causes intestinal pseudomyiasis, when larvae are accidentally ingested with food

Blow and Bottle Fly

• Species: Multiple species in the family Calliphoridae
• Size: 3/8 inch
• Color: Depends on species, metallic blue or green
• Behavior: Strong fliers, abundant in summer
• Breeding sites: Dead animals
• Lifecycle: 18-28 days
• Key characteristics: No stripes on thorax
• Impact: Nuisance, minimal impact on humans, impact on animals in schools with agricultural facilities

Secondary Screwworm Fly

• Species: Cochliomyia macellaria Fabricius
• Size: 3/8 inch
• Color: Metallic green and shiny
• Behavior: Abundant on corpses in warm, directly sunlit areas
• Breeding sites: Decaying animal flesh
• Lifecycle: 21 days
• Key characteristics: Thorax has three stripes
• Impact: Nuisance, minimal impact on humans, impact on animals in agricultural facilities, beneficial as a decomposer

Soldier Fly

• Species: Hermetia illucens Linnaeus
• Size: 3/5 inch
• Color: Black
• Behavior: Commonly crawl around areas surrounding compost bins.
• Breeding sites: Compost or animal feces
• Lifecycle: 30 days
• Key characteristics: Wasp-like, abdomen has two whitish areas
• Impact: Nuisance, minimal impact on humans, larvae known to occasionally develop in intestines of human beings and other animals (intestinal myiasis), but has beneficial impacts by making larval breeding sites less hospitable for house fly larvae

Dump Fly

• Species: Hydrotaea aenescens Wiedemann
• Size: 1/4 inch long
• Color: Looks like house fly with shiny, black body
• Behavior: Adults fly low to the ground and prefer to be in the dark
• Breeding sites: Garbage and fowl excrement.
• Lifecycle: 14 days
• Key characteristics: Shiny black thorax and abdomen
• Impact: Annoyance, transmits disease causing pathogens, but larvae are a predator of house fly larvae

Fly Identification – Small Flies

The three most common small flies homeowners deal with are the fruit or vinegar fly, the Phorid fly (also known as the humpback fly), and the drain fly (also called the moth fly). Eye gnats are a common problem in agricultural settings rather than residential neighborhoods but may have some effect on homeowners in rural areas. Small flies can be unrelenting in your kitchen or bathroom, and may spread to other areas of the house as well. By properly identifying your small fly, you can gain clues as to where they may be breeding.

Fruit or Vinegar Fly

• Species: Drosophila melanogaster Meigan
• Size: 1/8 inch
• Color: Tan head and thorax, black abdomen
• Behavior: Fly and hover over sources of sugar
• Breeding sites: Decaying fruit and vegetables
• Lifecycle: 8 days
• Key characteristics: Wings have an identifying “H-shaped cross vein”. Some species have red eyes.
• Impact: Annoyance, can contaminate food with bacteria

Phorid or Humpback Fly

• Species: Multiple species in the family Phoridae
• Size: 1/8 inch
• Color: Dull-black
• Behavior: Short, erratic flight, run across windows, walls and tables
• Breeding sites: High-protein decaying organic matter, e.g. trash can residue
• Lifecycle: 8-16 days
• Key characteristics: Wings have three posterior veins with no cross veins
• Impact: Annoyance, can contaminate food with bacteria and disease-causing pathogens

Filter Fly, Moth Fly, or Drain Fly

• Species: Multiple species in the family Psychoda
• Size: 1/12-1/8 inch
• Color: Tan to gray
• Behavior: Jump and fly short distances, wings held roof like over body at rest
• Breeding sites: Moist areas such as sewers, septic tanks, clogged overflow pipes.
• Lifecycle: 8-24 days
• Key characteristics: Wings mottled black and white
• Impact: Nuisance congregating indoors, but larvae are beneficial breaking down organic matter

Eye Gnats

• Species: Hippelates pusio Loew
• Size: 1/12-1/8 inch
• Color: Shiny black
• Behavior: Fly feeds around the eyes causing annoyance, enter buildings through open windows and doors
• Breeding sites: moist sandy soil with high organic matter, decaying vegetation and animal feces
• Lifecycle: 11-90 days
• Key characteristics: Legs yellow to orange-brown, wings with reduced venation, no spots or patterns
• Impact: Extremely annoying and persistent, can spread the organisms that cause conjunctivitis

Fly Life Cycle – What are Maggots?

To control both large and small flies in and around your home, you must break their life cycle. This requires knowing where they are breeding and cleaning the area before the larvae and pupae become adults. In the species description above, a range is given for each species life cycle. How long the life cycle takes depends upon ambient conditions, availability of food, and other factors.

True flies undergo a process called complete metamorphosis to become adults capable of reproducing. The stages of complete metamorphosis are egg, larvae, pupae, adult. A female fly lays her eggs on her filth of choice. Some species of filth flies prefer carcasses while some prefer fecal or vegetable matter. When the egg hatches, the larvae emerge.

Fly larvae are commonly referred to as maggots… the small whitish wormlike organism you have probably seen on the garbage when you forgot to take it out. The female fly lays her eggs in garbage or other organic matter so that her larvae, the maggots, will have immediate food upon their emergence. Depending upon the fly species and conditions, the maggots feast upon the filth into which they were born for a period of time, and then go into a “wandering stage.” This is when they crawl away from the original breeding site and look for a hidden, cooler, and drier place to pupate.

The fly pupal stage is similar to the cocoon for the butterfly. The fly larvae is protected inside a shell casing where it develops wings and legs and ultimately emerges as an adult fly.

The rapid life cycle of many flies contributes to the difficulty of fly control in many situations. Flies have an enormous reproductive capacity. House flies for example, can have a lifecycle of only 6 to 10 days and each female can lay up to 900 eggs in her lifetime. The fruit fly life cycle takes approximately 1 week, and each female fruit fly can lay 500 eggs in her lifetime. These astounding reproductive rates underscore and highlight the futility of trying to control flies after they become adults. Fly control happens at the breeding location.

How to Prevent Flies

Both large and small flies can be prevented with regular inspections and proper sanitation. By keeping a careful eye for problem areas and quickly addressing and cleaning areas where flies may lay eggs, you can minimize the impact of flies on your home. It is important to correctly identify problem flies and pinpoint their breeding sites. You will not control the infestation without identifying and eliminating the source.

Identification of the species will help you to determine the breeding site. County Extension resources are available to help you. Gather fly specimens from monitors, windowsills, and light fixtures. Individual flies captured for identification purposes should be held in a small vial of rubbing alcohol (70% isopropyl) to preserve key identifying characteristics.

When inspecting an area for potential breeding sites, check dumpsters and trash receptacles and drains. Look for poor sanitary conditions in any form, dog poop piled in the back yard, cat litter that has not been scooped, overflowing recycle bins ect. Look for cracks and improper seals on doors and windows. In addition, consider that many fly species can travel considerable distances. The breeding site may be in your neighbor’s yard.

Sanitation and Cleaning to Prevent Flies

*Products listed are not endorsements, just examples.

Many factors affect the specifics of your fly situation. Some of the considerations discussed below may not apply to you, but the goal is to begin thinking outside the box in looking for the fly breeding source.

Eliminating the area where the flies are laying eggs and the larvae are flourishing is key to successful filth fly control. Below are some general tips that may help you identify areas where sanitation can be improved.

General cleaning

• Clean spilled food and drinks thoroughly and immediately.
• Rinse and dry floor mats daily to remove food debris.
• Establish a regular cleaning schedule for floors and drains to eliminate food debris. Steam cleaners can help remove built up grime that flies can breed in.
• Regularly using enzyme and microbe cleaners for floors, walls, and drains greatly increase the effectiveness of regular cleaning. These products contain microbes that digest grease, grime, and food debris to eliminate food sources for fly larvae. Examples include:
  • Invade Bio Drain™
  • Drain Gel™
  • Bac-AZap®
• Inform family members and co-workers of the importance of placing garbage inside the proper containers. Garbage should not be left lying on the ground.
• Proper use of plastic bag liners in trash cans.
• All trash disposed in dumpsters enclosed in sealed bags.
• Ensure trash cans are being emptied at least twice per week (daily in high use areas).

Sanitation in Potential Breeding Sites

• Flies have an enormous reproductive potential. Flies can reproduce faster that you can kill the adults, so the key is to managing flies is to eliminate the breeding sites and break the lifecycle.
• Breeding sites may be indoors or outdoors.
• Areas where flies most commonly breed
  • Trash compacters
  • Dumpsters
  • Garbage cans
  • Kitchens
  • Cafeterias
• Inspect trash compacters and ensure that liquid and other solid debris are completely emptied.
• Dumpsters and garbage cans
  • Replace or clean frequently.
  • Install tight-fitting, spring-loaded lid that closes after use to minimize odors that flies use to find breeding sites and discourage fly entry.
  • All food waste from the kitchen, cafeteria and other areas should be discarded outside of the building daily.
  • Store trash in dumpsters and ensure refuse is collected regularly (once or twice a week).
  • Place dumpsters at least 50 feet from an outer door.
• Drains
  • Food debris going down drains is the most common cause of flies breeding in drains.
  • Using strainers to catch as much food material and dispose of in the trash is helpful.
  • In commercial facilities, do not rinse food debris on the floors down into the floor drains.
  • Regular drain treatments with enzyme/probiotic bacteria products (Biodrain, Bac-A-Zap, etc) will break down the goo that builds up over time in the drain.
  • Properly clean and maintain exterior drains in trash handling areas including loading docks and indoor floor drains to avoid accumulation of organic matter and liquid.
  • Leaky drains can attract many species of flies.
  • Promptly fix drains or electric garbage disposal units that leak or drains that allow food waste to accumulate under sinks or floors.
  • Remove any food waste that has accumulated under sinks or floors or in spaces at the site of the broken drain, and then clean the area thoroughly.
• Flies can develop in soil soaked with water used to clean garbage cans and dumpsters. Check these areas regularly. If you see maggots, scrape them up along with the soil and dispose of everything in a plastic bag sealed tightly.
• In areas with agricultural facilities, remove animal waste frequently (at least twice weekly).
• Manure may be:
  • Disposed of at a site away from the property, preferably on agricultural land where it does not pose a nuisance or result in groundwater pollution.
  • Composted in an efficient composting operation that generates minimal fly problems. High temperatures (>120 °F) generated by efficient composting will kill all immature life stages.
• House flies and blow flies, the species that most commonly invade buildings, usually develop outside and follow odors into the building.
  • Close doors when not being used that lead to the outside.
• Plastic bags used for waste disposal should be thick enough to avoid tearing or puncturing by insects such as yellow jackets.
• In food preparation areas, rinse all cans, bottles, and plastic containers before recycling or discarding.

How to Get Rid of Phorid Flies, Drain Flies, and Fruit Flies

The small flies that appear on your kitchen counter, sink, or pantry are likely either phorid flies or fruit flies. Often these irritating small flies can be dealt with by throwing out the over-ripe fruit and cleaning up any fruit juice from the counter or cleaning the juice drippings in the bottom of the trash can. However, sometimes it is much more complicated. Fruit flies and phorid flies lay their eggs in moist organic matter. Their presence tells you that somewhere in your kitchen there is a sanitation issue. Even a small spill behind the refrigerator can breed many flies. They may also breed in wet kitchen rags, drains, sink disposals, garbage cans holding trash juices, or a wet mop. Perhaps a bag of potatoes or onions got buried deep in the pantry. Keep searching until you find the source and clean it. Many times, there is more than one breeding site that must be located and cleaned. Until every breeding location is found and eliminated, the small fly problem will not be corrected.

Treating Drains for Small Flies

Often the source of a small fly infestation in a home or restaurant kitchen is the drain. For the homeowner, this is usually the kitchen or the bathroom sink, but many commercial kitchens and restaurants must also think of the floor drains. Grease, small bits of food, and other organic matter can cling to the sides of the drain and accumulate. This is an ideal breeding ground for small flies such as phorid flies, drain flies, and fruit flies. Recall that these small flies have a short life cycle; allowing these flies to reproduce unfettered will quickly lead to a severe infestation.

If you suspect a drain to be a small fly breeding site, you can perform a simple test. You can tape a plastic baggy over the drain overnight. If in the morning you have captured small flies, you know that drain is likely a breeding location. Likewise, you can place a piece of shipping tape over the drain to determine if the drain is infested with flies. Once you determine, a drain is breeding small flies, it must be cleaned and maintained.

Running water down the drain does not adequately remove the grime in which the flies are breeding. If possible clean the drain with a pipe brush. Scrub the sides of the drain as thoroughly and deeply as you are able. Because most of the drain is inaccessible, it may be necessary to use a drain cleaning product. Products that contain live enzymes and microbes actually eat (therefore removing) the fermenting organic matter in which the flies are breeding. These products are not pesticides and often have a pleasant citrus smell. They are easy to use and highly effective at cleaning inaccessible areas that are breeding flies. These products come in various formulations, from a thick viscous gel that coats the side of the drain, to a premixed foaming aerosol that clings to the sides and crevices of the drain. For commercial uses, these enzyme drain cleaners are available in liquid formulation that can be mixed with a foaming concentrate. With specialized equipment, your Pest Management Professional can regularly and thoroughly coat the drains to remove the slime.

As a homeowner, you should expect to treat the drain every day until there are no more signs of small flies. After the drain is clean, maintain the drain with regular applications of an enzymatic drain cleaner.

Another tool that is often used in treating drains is an Insect Growth Regulator, or IGR. IGRs on their own do not kill adult flies, rather they prevent the larvae from turning into mature adults capable of reproduction. This disruption of the fly life cycle gives you an advantage in the battle against flies breeding in the drains. If you choose to incorporate an IGR into your treatment protocol, be sure you choose a product that is labeled for usage in the drains. Liquid IGRs require specialized equipment to properly apply, but some IGRs are conveniently formulated as an aerosol to make application easier and faster.

Homemade Fly Trap

You cannot control fruit flies, phorid flies, or drain flies with traps alone. These flies reproduce faster than you can kill the adults. It is estimated that only 10% of the fly population is in the adult phase at a given time. That’s not to say, they do not serve a purpose. While you are busy locating the breeding source, thoroughly cleaning the infested area, and treating your drains, setting out fly traps can alleviate the irritation caused by these small flies. Fruit flies are not attracted to fly light traps like the other fly species are. However, fruit flies are attracted to vinegar traps. There are many pre-packaged fruit fly traps available that function perfectly well for this purpose.

A homemade fly trap can easily be made by placing a small amount of apple cider vinegar in a shallow dish. Cover it with plastic wrap and poke a few holes in the plastic wrap with a bamboo skewer or toothpick. Do not rely on this trap to solve your problem, again, you must locate and remove the breeding material for long term control.

Fly Traps for the Homeowner

Fly light traps can be a useful tool for alleviating flies, both large and small. However, fly traps should not be used as an alternative to doing the work that will really solve the problem. Locating and eliminating the source of the flies, the breeding location, is the only way to truly solve the problem. Even with the most stringent sanitary procedures, a fly can always slip inside.

Restaurants, manufacturing facilities, and other commercial endeavors should talk to their Pest Management Professional as to how fly traps may fit into their overall pest management plan. Many homeowners choose to install fly light traps in their homes to combat the occasional fly. These fly light traps range from a nightlight style with a 3×5 glue card inserted into the back, to a larger fly light with a 22-inch glue board. Still other homeowners prefer zapper style fly lights. If you choose to use a fly light in your home to either monitor for flies or eradicate the occasional fly, there are some things you should know.

Fly lights can be effective, but they must be properly placed and regularly maintained. Fly lights either use replaceable glue board to trap the fly or electrocution to kill the fly. Depending on the size and features you choose, the price can range from $25-$200. In kitchens or near food preparation areas, do not use a zapper or electrocution style fly light. Insect parts may scatter causing a bigger problem than the live fly! If you use glue board style, the glue boards must be replaced when they are full or otherwise dirty. In either style, light bulbs should be replaced once per year. After one year, the lights will appear to still be working, but the wavelength of the light has changed and is no longer ideal for attracting flies.

Proper placement on fly lights is paramount. To avoid drawing flies indoors, the light should not be visible from the outside.

In addition to fly lights, many non-mechanical sticky fly traps are commercially available that may be appropriate for homeowner needs. A popular model, such as Gold Stick™ (Catchmaster®), is economical and effective. Flies stick to the surface of the trap when they land, thus eliminating them as a nuisance. Some of these sticky traps come with pheromone attractants to lure the flies away from your BBQ or birthday party.

The most basic of all fly killing mechanisms is the old fly swatter; it is pesticide free and effective. HEPA vacuums are a great tool for a quick knockdown of indoor flies without the risk of contaminating surfaces with dead flies or insect sprays. Again, fly traps and other devices cannot alleviate the need for sanitation, but they may help to make a BBQ more pleasant.

How to Stop Flies from Coming Indoors

Integrated Pest Management places much value on the belief that preventing a pest from coming into conflict with humans is as beneficial as killing the pest. By enacting measures that physically prevent flies from entering your home or business, you may find no further fly control is necessary.
Ensure that your home is properly sealed, the doors fit tightly and door sweeps are installed if necessary. Keep windows and doors closed. Do not prop doors open. Ensure the windows have seals and the screens are maintained in good condition.

Certain commercial kitchens benefit from installing air curtains in the kitchen area. Make sure that the air blows out and not into the kitchen. To be effective, the air curtain must create a strong air flow. Studies show that air curtains, when properly installed and used, can keep out 80% of flies.

How to Get Rid of Flies Outside

As previously stated, fly infestations are an indication that they are breeding nearby. Once you find the source of the flies, and make the necessary changes, you will immediately see a reduction in the fly population. To get rid of flies outside, you must get rid of their breeding grounds. Pesticide applications are not a substitute for proper sanitation and aggressive elimination of fly development locations.

Studies have shown that flies are highly resistant to many common pesticides. Insecticide fogs that kill flying insects provide only temporary relief of flies and do nothing to solve a fly problem. In addition, fly behavior and rapid life cycle make it unlikely that they will contact surfaces treated with traditional pesticides. Rather than treat surfaces in barns housing animals, garages, fences, pool decks, foliage, and other vast areas where flies frequent with a residual pesticide, the best chemical option for fly control is a fly bait.

Fly Bait and Other Insecticides

Many new fly baits are available on the market and offer more effective treatments than fogs and sprays. Insecticide baits combine a food attractant and an insecticide. When the bait is consumed, the fly ingests a lethal dose of an active ingredient. Each active ingredient works upon the fly’s system differently, and ultimately causes his death.

Fly baits are an attractive option for outdoor fly control when you can not thoroughly solve the sanitation issue. For example, if your neighbor has horses, or you live across the street from the county landfill, you cannot eliminate or control those conditions. By placing fly bait out, you can minimize the fly impact on your family. Fly baits come in different formulations, granular baits can be placed in tamper resistant bait boxes and strategically placed to draw flies away from your outdoor activities. Fly baits also come in aerosol sprays. Other baits are granular but are mixed with water and either sprayed or painted onto surfaces.

Be sure to read and follow the label on any pesticide product. Place all fly bait products in areas that are inaccessible to children and pets. Also, think about the way you use your yard. Do not place bait on or near the table where the birthday party will take place. Try to draw the flies away from the party by placing the bait on the edge of the party area. Fly baits used on trash cans or other areas may be effective in reducing the number of adult flies if proper sanitation practices are followed.

Fly Resistance to Insecticides

Pesticide resistance is well documented in house flies. Pesticide resistance is when the insect consumes or comes into contact with the active ingredient, but it does not kill them. Similar to antibiotic resistant bacteria in humans, if a fly is resistant to the active ingredient, he will not be affected. This persistent resistance is one of the reasons we state that to solve a fly problem, you must find the source.

To combat resistance in the fly populations, it is important to rotate the baits you offer the flies. Each bait has a different active ingredient. If a product that used to work well but is no longer effective, resistance may be to blame. If the flies seem uninterested in the bait that you are offering aversion may be to blame. Aversion is when a pest no longer “likes that flavor”. Read the product label on your bait to figure out the active ingredient.

If you suspect fly resistance to your chosen product is building, choose a product with a different active ingredient. Switching to different brands will also help reduce aversion. It is best to rotate baits on a regular basis to prevent resistance or aversion from happening in the first place. If you wait until you see resistance or aversion it is too late…. That bait may never work again in the future. There are only a few baits to choose from, and if you do not rotate baits, it is possible they will all no longer work for you in the near future.

At the end of the day, fly control is all about sanitation. Locate and eliminate the fly breeding grounds fly elimination will follow. You can not spray your way out of a fly problem.