RSS Feed
Email this article
Printer friendly page

Ask Rick A Question


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


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!!
Notify me about new comments on this page
Hide my email
The box below is for visitor comments! Questions posted in this box may not be answered by Ask the Exterminator. For quickest response click on the "Ask the Exterminator a Question" link at top of this page.
Security Image:



More Articles Like This

  • Pipevine Swallowtail Caterpillar
  • Robber Fly
  • Get Rid of Gnats
  • Fly Control
  • Black Flies
  • Sand Flies
  • Horse Fly
  • House Flies
  • Garbage Maggots

  • Categories: