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Summary: The blowfly is a grouping of flies that includes bluebottle flies, cluster flies, and green bottle flies. The flies usually have a metallic coloration and are among the first insects found feeding on a dead animal.

If blowflies are an urgent problem you can try using fly bait such as Maxforce Fly Spot to kill the flies, sticky traps hanging nearby where they congregate, or pesticide sprays like  PT 565 XLO to limit or exterminate populations. However, pesticides should be used as a last resort, with improved sanitation being the primary method for getting rid of blowflies.

The blowfly is a pretty disgusting animal. Anything that feeds primarily on carrion and dung can be categorized in this way by my standards. The blowfly uses dead animal meat not only for food, but also as a haven to lay its eggs. When blowfly eggs hatch the blowfly larvae are referred to as maggots. The maggots use the dead animal or dung for food and they help to decompose it so it doesn't lie on the ground and stink up everything around it forever. That


is a great benefit for mankind. The term blowfly comes from an old English expression that referred to maggot infested meat as “fly blown”.

Although the blowfly is an important decomposer, it can also be a pest to humans. Because its food source is so nasty, the blowfly can spread diseases such as dysentery to people when the fly comes into contact with food that is consumed by humans. Blowflies also sometimes lay their eggs into the living flesh of livestock animals such as cows, goats, and sheep. Blowflies such as sawflies do millions of dollars of damage each year because these infestations can sometimes kill the host animal. Integrated pest management strategies such as introducing sterile males into the environment to reduce reproduction rates have been very successful in limiting the populations of blowflies and preventing damage to livestock.

Blowflies are the flies commonly seen flying around dung or roadkill. They are twelve to fourteen millimeters in length, with only one pair of wings. They are blue, black, or green in color and there is usually a metallic sheen to their exoskeleton. Most have large, bright red eyes. They live in all the contiguous United States.

Blowflies are attracted to food sources where they can lay their eggs. If you are having a problem with the shiny looking flies, then it is likely that they are reproducing somewhere nearby. Check garbage cans to make sure that the lids close securely. You might want to consider moving them further away from the house or giving them a thorough cleaning to reduce the smell of rotting garbage. Some flowers attract blowflies to pollinate them by having a scent like rotting meat. These flowers should not be planted in your garden if you do not want to attract blowflies.


Blowflies have short lives but reproduce very quickly. A single female can lay over 2000 eggs in her lifetime and eggs, under the right temperature conditions, can mature from egg to an adult in as little as ten days. This means that if there is a suitable place for the blowflies to reproduce in their populations can explode. A dead animal in a wall void might attract cockroaches, ants, or blowflies. Removing the blowflies' food source will quickly reduce the blowfly population as adults die off, and the maggots that will soon become adults are no longer present.

Another interesting note about blowflies is that they are often used in forensic science to determine the time of death of a human body. Forensic entomologists use the development of blowfly larvae to determine how long a body has been dead. A gory but very useful method for criminal investigators.

Click here to watch my short video on how to control flies.

Ask Rick A Question


16 Jul 2012, 21:25
Good Evening,
I'm haveing fly trouble again. Every few weeks the flies come in swarms and congregate on all the windows inside. We kill them, but this only briefly provides relief. One thing I notice is the majority seem to come fro in between the front door and the screen door. I looked around and notice some of the wood looks rotten. Cand these green metalic flies breed in rotting wood? I have searched far and wide for dead animals inside and out. I have sprayed the yard with OFF insect killer. My garbage cans are far from the house and bleached just to be sure. We take the trash out every night and keep a very clean home. My neighors have two dogs so its possible the flies could come from there but they dont seem to have a fly problem. These flies a driving me insane!!! Thank you for your help. Great job at keeping up with your website. I notice the questions get answered very proptly.
Ask the Exterminator
17 Jul 2012, 09:56
Green bottle flies attack the carcasses of dead animals or decaying matter like dog feces. The reproduce very rapidly, so populations explode. You may have to have a talk with your neighbor about picking up after their dog.
20 Jul 2012, 11:41
It's nice to see I'm not alone with this problem. Over the course of 3 days I've been killing about 20 flies each day at the windows. I went downstairs into basement and discovered numerous dead fly bodies on the floor and a few live ones around the window. When I sprayed insecticide, there was a buzzing from the wall beneath the window. I'm assuming that a mouse or some other tiny rodent died in wall. This is beneath the window egress from basement. I don't want to have wall torn out so will hope they disappear in time. Terminex is coming out to have a look today. Made my skin crawl when I heard the buzzing. They must be coming up to main floor from A/C grates...
24 Jul 2012, 22:58
Right after I posted my 2nd post we finally discovered where the flies were coming in from. In our utility room off the kitchen, there are some tiny windows all along the outer wall near the ceiling. One of them on the far end had a small crack in it allowing the flies to come in. In that window we saw probably a hundred flies swarming. My husband killed them all. We never saw a dead animal but there must have been one near our house. Once my husband killed those flies we never saw another blow fly. Thank God. They are a total annoyance and extremely disgusting.
08 Aug 2012, 00:48
About 2 days ago I noticed lots of flies all over my kitchen window and at first thought nothing of it even though I am a paranoiac when it comes to shutting the door. In those 2 days I've been killing 2-4 flies a day even though all windows are closed. They're bright green so I know they're blowflies but I found no rotting food and have never seen a rodent! Where else could they be coming from and when will they eventually die out?
Ask the Exterminator
09 Aug 2012, 16:57
The flies could be coming from a nearby compost pile or even dog feces in the yard.
14 Aug 2012, 21:35
I've been having 10-20 blow flies in my apartment lately. Last week, I found that the maggots were coming from the kitchen garbage. I took out the garbage, killed all of the maggots lying around, and lysoled the crap out of the bin (it's one of those bins where you step on pedal to open the lid). I also swept and mopped the kitchen. I don't see any more maggots crawling around. I've been killing the flies I see when I get back from work. How long does it usually take until the flies go away completely (given that I have eliminated the maggots)?
Ask the Exterminator
15 Aug 2012, 20:34
If you've really eliminated the larvae, a simply spray with any fly spray product will instantly kill off the remaining adults.
18 Aug 2012, 01:28
In my case, i don't see them flying around. However, I find them by the dozen, dead, next to my two basement windows - nowhere else in my house, just the basement windows. What could explain this? and what can I do to solve this?
11 Sep 2012, 18:14
My home has had blow fly infestation two times. Each infestation occurred, only, after the home was re-roofed, first Sept-1996, next late Aug 2012. This time I removed the, now unused, chimney and sealed it's opening in my basement and have experienced fewer flies. Next, I'll hang a 'no pest' strip in the attic and seal the chimney exit in my attic floor. A neighbor ground feeds, against city statute, all types of wildlife in her yard; this draws mice. Looks like I'll complain to city inspector's every day until she stops.
Renee Mak
13 Oct 2012, 19:02
There was a decomposing something in the walls of the basement apartment that I live in. My landlords were unable to find the body so they got a pest-control level deodorizer to deal with the smell. But now I have blowflies!! There are so many, big ones and little baby ones. It's very distressing and they aren't sticking to the sticky fly traps I have been hanging (maybe not attracted to it?). So far I've just been attacking them with the vacuum cleaner whenever I see them. I'm a very clean person and it's just the matter of the decomposing mouse. The smell started about 3 or 4 weeks ago and it primarily gone now. How long will the blowfly problem last?
Ask the Exterminator
15 Oct 2012, 09:39
The flies will remain until the carcass of the dead animal has been completely consumed by the flies.
20 Jul 2013, 09:23
I have done my best to seal off the wall through AC sleeve in my second floor NY apartment. I never open the windows anymore. I understand there are cracks in the facade - could large blow flies be entering through these? (They are really large flies). Also, I went to open a window to clean and was horrified to see around 40 flies dead, lying between the screen and the glass window. What next steps should I take? I have 60 dead flies right now on clear window stickers and a light trap. I would complain to my landlord (this is a condo and I rent from the owner) but don't know what to ask him to do.
27 Jul 2013, 08:53
There are flies that are flying around in the living room. All the windows have been closed. The basement and attic have been checked and there are no flies in either room. For a few hours you don't see any flies then they appear. This is puzzling where are they coming from.
Ask the Exterminator
27 Jul 2013, 09:52
What kind of flies? Knowing the species will help you learn why they are present and where to search.
27 Jul 2013, 10:29
They are black flies. They crawl and fly.
28 Jul 2013, 16:19
we have been getting an infestation of black flies for the pas three years and have owned our home for over 30 yrs. nothing dead, no garbage around..what is it???it last 1-2 days then stops,,every!!!! parents are elderly and getting stressed!!
30 Jul 2013, 14:26
I found my inside garbage bin infested with maggots, bins are now outside permanently and floors, units and entire kitchen was bleached on numerous occasions. I've checked every area, knook and cranny and no more maggots to be found. 10 days later and I am coming home to 20-12 blow flies (shiny green/blue body) on my kitchen windows. There is absolutely no food or anything they can feed on and I've cleaned away the maggots over a week ago. What can I do??? How long could maggots last without a food source? Windows and doors are shut all day so must be coming from inside. I cannot find a single trace of maggot anywhere!
Help please!!
Ask the Exterminator
30 Jul 2013, 14:46
There really is no secret to this. The flies are breeding in some type of organic material that has been left behind. I cannot tell you where to look, but I can suggest creating some homemade blowfly traps.

Bait the traps with a piece of meat and place the traps in locations where you think the flies may be breeding. Don’t place them near the window. All flies are drawn to light coming from windows. In fact, close the shades, if possible. Check the traps in the morning. Where ever you catch the highest number of flies would indicate you are closer to where they are breeding. Intensify your inspection based upon the number of flies captured.
11 Aug 2013, 11:23
We have kept 7 chickens for about 3 years and although we clean the runs out often there is still droppings in the grass etc. We have had a massive influx of flies this summer and can't seem to shift them - any ideas?
29 Aug 2013, 11:38
I had some trash in my kitchen for way too long. I thought the box was full of empty beer bottles but it turns out it had rotting meat in it. After cleaning up the trash I found fruit fly eggs and bowfly pupae (looked like brown rice) under and in the boxes.

I cleaned my kitchen and floors, and no longer keep trash in the house.

At first I noticed a ton of fruit flies in my house and after 3 days of vinegar traps and spraying they are almost all gone. But then yesterday I came home to about 15 dead adult bow flies and about 10 that were still alive but I killed through the night.

I searched my entire house last night for more pupae, all the cabinets, floors, under and around furniture, I even removed some base boards and found only 1 near my front door.

What's the best thing for me to do next?
Should I call an exterminator? Should I use a bug bomber? I'm leaving town next week and don't want to come home to a nightmare! Thanks!
Ask the Exterminator
03 Sep 2013, 16:31
Sounds like you are doing all that can be done. Inspection is the key and no pest control company will be more familiar with your home than you. Use a flashlight and mirror to check behind and under tight spaces, too.
11 Sep 2013, 21:29
I have green and blueflies, very few have entered my home buy enough to irritate us. Unheard the Cary desieses? Do they bite? Also they surround our porch light at night- what's up with that?
15 Sep 2013, 14:20
We have had an infestation of 100s of small black flies in our screened in porch. There is no trash nearby or any rotting or decaying wood for them to breed in. The porch is built on a deck with space underneath. Is it possible they are breeding below the deck and coming up through the cracks in the deck boards? We are baffled. They don't seem to have a metallic body - just black and fairly small. They are also sluggish and easy to swat - but there are way too many to kill by hand. Any suggestions? Thank you!
27 Feb 2014, 13:11
hello - i recently moved to london to live with my cousin in his 3 story house. when i moved down i learned of a rat problem he had been having - there was a lot of scratching and running about between the kitchen ceiling and 2nd floor. they called in experts to investigate and they had cut out a large piece of the ceiling in the bathroom to investigate/lay poison etc to catch the rats - note the smell had been pretty bad in this room (im not sure if its just rats in general or a dead rat) - i am certain there is a dead rat now as there has been a bunch of flies in that room specifically and inside the house - i've done my best to get rid of them and i even patched up the roof with tin foil and a lining of copper mesh finishing it off with tape around the edges so it was properly covered up. i also taped up the bottom of the door because i seen a fly crawl out that way. my neighbour has had a problem with a lot of flies a month or so back and they have given me some insecticide to spray where i know they are coming from. i guess my question is, is trapping the flies gonna help or will they just find another way out? i can also hear more rustling of rats again and even a loud scratching beneath the floor of my room which is directly underneath the kitchen - i've moved my stuff out that room and into a guest roof and used some fly spray to take them out. can you give me any advice or help? they are getting on my nerves and i sometimes think i can see/hear them - also i just killed another fly about 10 minutes ago, after patching up the hole yesterday - was wondering what the typical ways a fly can get into the house is other than windows etc. thank you!
30 Apr 2014, 20:05
i have had a squirrel in my ceiling for quite some time and i think it may have died because my house is infested with green house flies. i dont smell anything.
i also can't call an exterminator because there is no way into my ceiling to remove the dead source.
how long would it take for the rodent to fully decompose and the flies to go away?
Is there any other way to get rid of them?

Saubirah Hack
30 Jun 2014, 01:25
Hi, so I have a problem where I think that something may have died in a yard nearby my home but I can't find the source. I have been killing cluster flies for the past five days. Yesterday I found like 50-100 flies even though the storm windows and screen doors were pulled down on. I recently sealed up the holes in the the windows and have been spraying the window panes with ortho home defense insect killer and Raid. I haven't seen any flies since but how often do I need to spray the windows in order to ensure that they stay away from my apartment? I'm gong out of town in a couple of days and I'm really worried that I'll come back to an apartment full of flies!
Xander MacLeod
01 Jul 2014, 11:51
Like many people here, I've been experiencing problems wth house flies recently. A little over a week ago, i noticed a large number of flies seeming to get into the house without any windows or doors being open. I usually just opened a window and proceeded to drive them out, but then the number of them began to grow.

I can't figure out where they are coming from. I have isolated it to 'somewhere' in my bedroom, as when i have all the doors closed and return to the house, it's usually my bedroom where a new congregation of 10 or so flies are buzzing around. Ive done a massive clean out of the bedroom, including removing all trash, going through cupboards, wardrobes, drawers etc, but cant find anything. Ive hung fly paper up in several locations around the room to try and see where I can get the greatest amount of flies to further pinpoint the source, but the paper doesnt even seem to cause them to stick to it.

I live in the UK, in a ground floor flat, and my bedroom is right beside an easterly facing wall (it's summer and very warm at the moment). The only thing I can think of is that something must've died underneath the floorboards, behind my radiator or 'behind' (now inaccessible) my fitted wardrobes. However I cant smell anything funny in my room. Not only that I recently just had my flat carpeted with underlay put down so i have no idea how the flies are getting mainly into my bedroom if there was an issue under the floor.

I cant find anything, so I was just wondering if there's anything I can do to narrow down where the infestation source is, and if its humanly inaccessible what options I have.

Please help!
18 Jul 2014, 07:30
I have a dead bird in my chimney nearly ten days now had greenbottles in my lounge roughly 20 three days running then nothing for twelve days and today just killed around 30 how long before they stop as afraid to go on hols
Xander MacLeod
18 Jul 2014, 09:10
Just discovered where the flies were coming from. Turns out there was a vent in my room that was slightly ajar from the wall, which i couldnt find because it was behind a false-backing piece of mdf behind my headboard. Having taped it up with fly-tape and masking tape sure enough the flies now no longer get into the room.... phew. Its only a temporary solution, but it'll do for now. I was looking for a food source all along when I should have been looking for a 'way in'. Hope the rest of you here have some luck combating these pests.
jenny ortega
30 Oct 2014, 02:34
Hi tonight I. Noticed one blow fly in my room I have my baby in there with me and his diapers r thrown in my trash I throw the dirty diapers away In my trash to the garabage but could the smell of the poop attract them? Do they lay eggs in ears ?
angela gadreault
05 Apr 2015, 22:31
I have maggots falling onto my kitchen counter from behind Mt cabjneys. I noticed kne, then two then three etc. I removed ally food and know now because I am watching them fall. My husband put out bait to kill rats and now a week later I have this maggot problem. How long is this going to last and can I do anything. We live in florida and I don't think we can get to the source due to no attic space or it might be in the wall
17 Apr 2015, 17:30
In the last week, I have killed 50+ Flies every day. Trash is out, I don't know what to do. Both kitchen windows are covered with those disgusting flies! As I am typing this I have gotten up no joke- 10 times to kill more flies. They seem to magically appear at the kitchen windows seconds after I just killed a bunch. I feel like I am going crazy. Where are they coming from? I don't know where else to check. They're not outside they're inside! I was thinking because of the construction in front of our house- FB but then they would be outside right??
Rick Steinau / Ask the Exterminator
17 Apr 2015, 18:08
Look up cluster flies on my website.
15 May 2015, 15:19
Hi I run an animal shelter in Florida. Because of the warm weather year round, flies are always a problem. We are having a particularly bad time of them this year. People come in and out constantly and with open litter boxes, even though cleaned regularly, there is no discouraging the flies. Is there a pet safe method I can use to get rid of them? They also like the water/food bowls and this drives me crazy!!
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