Life needs to stop finding a way

September 13, 2018 1:20 PM

We don't keep our doors open. Windows all have screens. No food left out. Dishes done daily. Trash taken out regularly. Litterboxes clean. The house in GENERAL is clean. No dead bodies in the basement. And yet we are still bothered by flies and have been for weeks now. Where the heck are they coming from?

I live in upstate New York in an old house. The nextdoor neighbor DOES leave her door open practically all the time and does not have flies (though she does have ants and we don't, so... at least there's that). We never had the problem until a few weeks ago and I am at a loss. To give you an idea, I put up a new fly ribbon over the kitchen sink two days ago and it now has at least 30 dead flies on it. Where could they be coming from? And how do I make them go away forever?

posted by rabbitrabbit to Home & Garden (30 answers total)

There's a dead mouse behind your fridge providing a fine home for maggots.
Happened to a friend back in college but for her it was a squirrel and it was up under her sink. Fun!
posted by phunniemee at 1:27 PM on September 13, 2018 [4 favorites]

They may be hatching inside your house, on a carcass in the walls, on missed fecal matter from the cats, or something your shoe tracked in and left on the carpet.
posted by Iris Gambol at 1:27 PM on September 13, 2018 [1 favorite]

I live upstate and had a problem like this one summer in the basement. I put up 6 flypaper traps and they filled up. I never found what was the cause but I'm assuming that a mouse died somewhere.
posted by bdc34 at 1:28 PM on September 13, 2018

Or - spilled food now rotting on/around/beneath your kitchen trash bin.
posted by Iris Gambol at 1:29 PM on September 13, 2018 [1 favorite]

The garbage disposal is another possible source of you don't run it regularly.

DIY wine bottle traps usually work well for me. You can leave a bit of wine in the bottle or add some juice or sugar water, and add a drop of dish soap. If you don't drink wine, anything with a narrow neck works (but I recommend avoiding anything clear so you don't have to look at the dead flies!). This works really well with tiny fruit flies, I'm not sure how well it would work with larger flies.
posted by insectosaurus at 1:29 PM on September 13, 2018 [2 favorites]

Could be cluster flies which get active this time of year. There are a few ways to deal with them, but there's not much you can really do as they have already been there for a while
posted by GuyZero at 1:32 PM on September 13, 2018 [8 favorites]

Flies are incredible at breeding. If you have some flies indoors and some food for them (which can be anything), you will have flies.

What you need is airflow. Your neighbor is onto it. When I get a fly infestation, I make sure to blow out my house. It is uncomfortable, but you don't need to do it for more than a couple of days.

I've just moved into a new home and there are fruit flies and I hate them, but I won't be able to blow them out for the next week because I'm traveling. My plan is to remove all possible foods and open all the windows I can without inviting burglars. Can't say if it will work.
posted by mumimor at 1:33 PM on September 13, 2018

We had this problem in an old house I lived in once. None of us were willing to kill the flies and they bred. Finally I figured out the ole' cup-and-paper trick and spent an hour or two catch-and-releasing like 30+ flies. There were a few strays over the next week, which I was diligent about evicting. Problem went away after that.
posted by aniola at 1:34 PM on September 13, 2018 [1 favorite]

garbage disposal. Any drain with crud in it down deep somewhere. Pour lots of boiling water down likely culprits. And if your dishwasher has that little drain pop up thing by your kitchen faucet, that nobody ever checks? Check that.
posted by fingersandtoes at 1:36 PM on September 13, 2018 [4 favorites]

My intuition is that there's something which has ceased to be somewhere in your house. I'm remembering a really unfortunate version from about twenty years ago that resulted in lots and lots and lots of flies. You want to find whatever it is.
posted by Making You Bored For Science at 1:52 PM on September 13, 2018

We had a fly "situation" about a year ago and it turned out to be a couple of dead mice in the attic.
posted by blurker at 2:08 PM on September 13, 2018

We had a mysterious persistent swarm of flies at work a while back. The source became immediately obvious when someone finally opened up the office of a co-worker who'd been away for several weeks. Mouse corpse right in the middle of the room.
posted by Secret Sparrow at 2:26 PM on September 13, 2018

"I've just moved into a new home and there are fruit flies and I hate them, but I won't be able to blow them out for the next week because I'm traveling. My plan is to remove all possible foods and open all the windows I can without inviting burglars. Can't say if it will work."

I'm confused about this plan. Maybe it depends on where you live. Near Denver was the only place I've ever lived where you could leave a door or window open for any length of time and not be swarmed by armies of insects. Here in Texas, leaving a window open for even a few minutes is basically begging for moths, mosquitoes, and god knows what else to fly in and make itself at home. I do my best to turn off my phones screen and have lamps off in living room when I go in-and-out to smoke, yet every time there will be at least one new arthropod foe inviting itself in. I make sure to never kill spiders I find indoors so hopefully they can more quickly snatch whatever pests get in. If there were a service to put more spiders in your house, I would gladly subscribe, sorry geckos.

Finding whatever they're breeding from can be difficult, could be any number of dead critters what died somewhere in the home. Often they don't stink until you're right up on them, hopefully you don't have to just wait it out and hope they don't find anything new to breed in.
posted by GoblinHoney at 3:10 PM on September 13, 2018

My vote's for something larger than a mouse dead within the walls. I wrote a comment about our nightmare fuel situation several summers back that might help you. Even a stray cat turd left behind some furniture during the hottest weeks of summer wouldn't provide enough food to sustain a fly infestation like that.
posted by blerghamot at 3:10 PM on September 13, 2018

The family I nanny for had flies due to a dead squirrel in the chimney. So could be something like that, as others have said!
posted by sucre at 3:25 PM on September 13, 2018

House plants can be a source of rot, and therefore a source of flies.

I had an issue with flies once, and the answer was gross, but easily managed: Hair and dirt trapped in the drain of my sink. I made a definitive determination by closing the sink drain with a stopper (and added a small puddle of water atop that for confidence), and then put a strip of clear packing tape over the overflow hole near the top edge of the sink.

Any bathtub you have could also have this issue, and means of testing.

Started to see flies on the tape, and then I knew. After that, I pulled up the sink-stopper, removed the U-bend (aka P-trap) from under the sink, jammed with some rags and then taped it shut, and filled the sink, to the brim, with water as hot as the tap would let me. I also cleaned what I would with a toothbrush, a kind of zipper-like cleaning gadget (It's like a snake but made from the same plastic as zip-ties), etc. They were living in the two channels inside the sink bowl that connect the drain to the overflow, so I concentrated my cleaning through that. Breaking up the gunk let it wash out. Seeing inside the sink can be gross, and it'll take some time to adjust to the knowledge that there's something that gross so close to where you clean yourself, but that's life. Also, don't sweat the slime mold you'll also come across; it's harmless unless it's dark in color, most likely.
posted by Sunburnt at 3:37 PM on September 13, 2018

This is the time of year for cluster flies which aren't necessarily attaching to some dead thing. My combination of stuff was to use the sticky traps near windows (they seem to like to be inside but near warm/sunny windows) and then pick a time when I was going to be out of the house and spray fly killer spray around the windows where I thought they were getting in. They may be attaching to a dead thing in the outside walls and it's pretty hard to track it down but you can at least encourage them to not come inside your house.
posted by jessamyn at 3:37 PM on September 13, 2018 [2 favorites]

It could also just be flies in a drain somewhere, which can be dealt with accordingly.
posted by limeonaire at 3:44 PM on September 13, 2018 [1 favorite]

There is a tray under your fridge. If something icky drained from the fridge something could be breeding there.
posted by beccaj at 3:59 PM on September 13, 2018

Something similar happened to us and it was a rotting bag of potatoes way back in the pantry. No bad smells or other warning signs. So gross.
posted by jraz at 4:06 PM on September 13, 2018

What kind of flies are we talking about? If you can post a picture of the flies on your flypaper, it might be possible to identify where they might be breeding. My advice would be different for houseflies, drain flies, bluebottle flies, or fruit flies.

This time of year, I always get a few fruit flies that come in with the produce I buy at the farmers' market.
posted by Johnny Assay at 5:25 PM on September 13, 2018 [2 favorites]

Pour a big pot of boiling water down your shower and sink drains, follow it up with large quantities of straight bleach, then run the water for a while. DO NOT POUR BOILING WATER IN YOUR TOILET unless you want a shattered toilet bowl.
posted by erst at 5:33 PM on September 13, 2018

Seconding the notion that fly ID will help you correctly solve the problem. There are literally a million species of Diptera, probably several thousand in NY state, falling into maybe a few dozen classes of functional types.

Know your enemy, is what I’m saying.
posted by SaltySalticid at 5:40 PM on September 13, 2018 [1 favorite]

Nthing dead animal. We had a mysterious fly infestation that was only mysterious for about 2 days before we could smell the dead rat. It was in the crawl space and I don't know exactly how the flies got from there into the house but they were everywhere. In fact mostly in a room far from the carcass. But that is DEFINITELY where they came from.

So what I'm saying is, you DO have a dead body in the basement.
posted by raspberrE at 6:35 PM on September 13, 2018

Does your basement have any outside access? When I've had a problem with flies in my house it has either been:
a) dead mouse in the attic
b) garage and basement doors left open, allowing flies to come in and the somehow make their way through the rest of the house
posted by TwoStride at 7:40 PM on September 13, 2018

In my house it’s always drains. Boiling water and bleach might do the trick.
posted by mygothlaundry at 8:02 PM on September 13, 2018

Cluster flies or attic flies come inside this time of year. You’ll know them from regular bluebottle or iridescent flies because 1) their bodies are larger and a sort of blackish grey, 2) they fly much, much slower than regular houseflies, to the extent that you can vacuum them right off the windows, and 3) they’re called cluster flies because they congregate in masses on southern-facing windows, attics, and light fixtures. They come in through cracks in your eaves in search of warmer temperatures.

Facts about cluster fly infestations that may put you at ease a bit are that their primary breeding grounds are actually earthworms, so the flies haven’t been collecting on corpses or cesspools, so they’re not as big a threat to health as a housefly; and best of all, they’ll go away when their food supply, earthworms, go away. Unless the infestation is very, very bad, the best bet is just to wait out the season, put up some sticky traps, and make a game out of vacuuming them. Here’s where I found my info when we had them a few weeks ago.
posted by Queen of Spreadable Fats at 9:22 PM on September 13, 2018 [1 favorite]

We had a similar issue with fruit flies, and it turned out that our kitchen sink had developed a minor leak in the wall, so was providing water and mold (food) for them.
posted by lab.beetle at 4:32 AM on September 14, 2018

I just dealt with my annual infestation of cluster flies (thanks Queen of Spreadable Fats and GuyZero, now I know what to call them). About 50 of them appeared yesterday in my apparently sealed screened porch. They always find a way in. They seem to know that "Winter Is Coming".
I deal with them with an hour of swatting.

It seems reasonable that for thousands of years, the predominant theory of life was spontaneous generation.
posted by H21 at 9:37 AM on September 17, 2018

One time we had an abandoned dish with a big chunk of aging, uneaten, wet cat food. On closer inspection, it was full of maggots. They were hard to see because they were smaller than I'd have expected, and they were not on the surface of the chunk where the cat food was dry, but rather, burrowing through it where it was still kinda moist in the middle. This one little dish caused a weeks-long, very annoying infestation of few dozen flies.

We lured them outside at night by turning off all the lights in the house, and turning on the porch light. The flies went to the light, which is to say, outside. We also made use of flypaper and the dustbuster (empty it outside or the live flies will just escape back into the house). Ugh.
posted by pseudostrabismus at 9:06 PM on October 21, 2018