Shoo fly, please

August 20, 2024 6:28 PM

My apartment suddenly has several big flies in it totally out of the blue and I have no idea why.

I live in a small fourth floor apartment in a large building. I have two window units so it's not unusual to get a fly or two in the summer--I think they come in through the air conditioner? I'm honestly not sure but that's always what I've assumed.

I went out this evening for about 2.5 hours. I didn't think I saw any flies in the apartment earlier in the day, though there could have been one going around. I came home and there are several big flies swarming around the lights in the living room, sitting in the window, or flying maniacally around the room. I am so so grossed out and can't figure out where they came from or why they're suddenly all here?

I cleaned out the cats litter and took out all of the trash including the litter genie yesterday. The litter and trash were no dirtier than they usually are. I just vacuumed and wiped down a bunch of surfaces and took out all of my recycling. My apartment is clean, probably cleaner than it usually is, and now suddenly I get a full blown fly infestation? I've never had this many flies before. I've been walking around trying to find some kind of source or secret pile of trash or something to explain what's going on here but I have nothing.

Any suggestions on what happened here and what I can do? I feel like I need to find the source but I seriously have no idea where they're coming from. I also have no idea how to get rid of them?? Maybe a trap but God, EW, I'd seriously rather not have to dispose of all of them. The only benign cause I can think of is the temperature dropped probably 15-20 degrees the past couple of days and we got a cold rain so maybe they're all coming in for shelter? But how are this many crawling in through my air conditioners? I don't see where they'd be getting in; there aren't any obvious openings. How do you even seal a window unit like that to keep out bugs?

Sorry that's a million questions; I'm just horrified.

Thanks!

posted by Amy93 to Home & Garden (24 answers total)

Fly tape works really well, it should keep attracting them until they're gone since you've taken out all the possible internal sources. One more thing if you haven't done it recently, clean out your garbage disposal by running it with water and ice cubes.

I'm just now realizing this was pretty weird, but when my brother and I were young, we left a window open and like 20 flies came in. We shut them in that room for a "fly museum" and without a food source they did not take long to die. I don't know if that helps the situation feel less gross, but including it just in case!
posted by Eyelash at 6:45 PM on August 20, 2024

what I can do?
fly-swatters are surprisingly effective & inexpensive
posted by HearHere at 7:03 PM on August 20, 2024 [5 favorites]

Had this issue over several summers. Some years worse than others...Worse year I came home one hot day to find 7 or 8 flies flying around in the living room. Then I looked at a window which was closed and saw 20 or 30 between the outer window and the inner window Luckily I had Raid flying insect spray. I opened the window slightly and sprayed the the raid and closed it quickly. 10 minutes later they were all dead. I then hunted down the ones in the living room and when they landed I sprayed them with a short blast of raid. Eventually I got them all. In my case I think they were coming from the interior section between the outer brick wall and the inner drywall, somehow. Inspect your apt for any small cracks or holes. Spray there. And around the air conditioner. I have cats my whole life and did not spray anywhere they would possibly lick. Some sprays are more pet friendly than raid. I also have invested in a 6 dollar fly swatter, pretty effective.
posted by Czjewel at 7:17 PM on August 20, 2024 [1 favorite]

This happens in our 3rd floor apartment and we finally figured out that if we have the back door to our unit open for even 10 seconds, large flies enter our apartment. I don’t know how they zip in so fast, but they do. They only come up the back stairwell and subsequently our back door because the garbage cans for the whole building are at the bottom of that staircase. Could it be something like that?
posted by seemoorglass at 7:22 PM on August 20, 2024 [2 favorites]

Did you do anything different than normal with regards to leaving blinds open/lights on? I once put the antenna for my tv in between the blinds and the window for better reception and the next day there were several flies inside, mostly between the blinds and the window but some inside past the blinds.
posted by I paid money to offer this... insight? at 7:36 PM on August 20, 2024

If it would help to reframe them as entertainment, there are both fly zapper rackets and fly guns... though this fly crossbow is, imo, getting to be a bit much.
posted by stormyteal at 7:40 PM on August 20, 2024 [2 favorites]

I think this is for old fridges, but I had a drip pan under it that got gross and well, ick. Maggots and such.
posted by beccaj at 8:51 PM on August 20, 2024

Check all the drains, and - sorry - the soles of your shoes (you may have tracked something in).
posted by Iris Gambol at 8:55 PM on August 20, 2024

I once had a second / top floor apartment with tall ceilings and ceiling fans. One night I was sitting on the couch and little light brown wormy critters kept bouncing down to random places around the living room. Turns out that maggots (baby houseflies) were falling down from the attic above, through a crack above the ceiling fan, and being flung around the room. Something had died up in the attic.

That's my guess for what is happening here. Something died somewhere and the flies are all over it.

Seconding fly tape.
posted by intermod at 9:04 PM on August 20, 2024 [1 favorite]

fly-swatters are surprisingly effective & inexpensive

It's true. You may have to wait a while for the flies to get tired and stop flying around, but once they land, swatting is easy.
posted by Rash at 9:09 PM on August 20, 2024

Every once in a while a fly swarm happens inside of a human home. It sucks and there is very little you can do to prevent it because we can’t live in hermetically sealed units. Something probably died in a vent or crevice or whatever and there is a teeny space into your home that they are heading towards. It’s not your fault and you aren’t like, secretly extra gross or harboring poop or whatever.

Glue traps for flies are pretty good. The best trick is to get the clear kind, and put them on a window that has an outdoor light by it, and keep the light on outside while everything is dark inside. Wake up the next morning and yup, dozens of flies stuck conveniently in one place for you to get rid of. I had to do this (using the window on my kitchen door) for a few weeks a couple years ago because of an escalating fly issue and it worked quite well, I just had to be patient. If you don’t have a setup like that, or maybe a window that has a bright street lamp in front of it, you could rig something similar by setting up a moat of glue traps around a small lamp in the corner, including up along the wall. You can make flies go roughly where you want them to go by strategically controlling light.
posted by Mizu at 9:43 PM on August 20, 2024 [1 favorite]

Odds are something died in/around your place, sorry to say. (This happened to me once - I almost lost my mind.)

Kill as many as you can. The racquets are good. Eventually the flies will go away (once they’ve done their job as part of the cycle of life).
posted by cotton dress sock at 10:20 PM on August 20, 2024 [1 favorite]

This happened to me at the end of last year: we had an unusually warm day in December, and suddenly there were giant sleepy flies EVERYWHERE in my downstairs room. It was deeply unpleasant. Because they were slow-moving, I was able to trap a few under glasses and escort them out, but after a while I was just too distressed to be able to keep doing that, and resorted to a couple of plug-in ultraviolet fly zapper things. They work, especially overnight in an otherwise dark room. In mine (UK, so no point linking), the dead flies collect in a tray at the bottom that you pull out and tip into the kitchen bin - with your eyes closed, if you like.

Just for info, in my case, they were in a ground floor room and had almost certainly come up from under the floor - and a dead rodent was very likely involved, even though I hadn't smelt anything nasty.
posted by ManyLeggedCreature at 12:42 AM on August 21, 2024 [1 favorite]

Sadly I must report that insectivorous plants are not effective at controlling flying bugs in the house.
posted by Hogshead at 5:31 AM on August 21, 2024 [2 favorites]

I have had swarms of cluster flies on my screened porch in fall. They are slow and a flyswatter takes care of them.
posted by H21 at 7:13 AM on August 21, 2024 [3 favorites]

Cluster flies don't eat dead animals. They are just looking for a warm place to hibernate.
posted by H21 at 7:15 AM on August 21, 2024 [2 favorites]

It happened to me, suddenly I had like 30 house flies buzzing my living room windows trying to get out. I'd opened the outside door to my deck *briefly* I swear and you'd think I would've noticed the invasion. An old house though, and someone said they can live in the walls? Anyway, ran to the hardware store for flying bug spray and used my fly swatter. Had guests coming so drastic measures needed. This was in the summer.
posted by TWinbrook8 at 7:45 AM on August 21, 2024

There is also a humane solution to the problem that does not require dealing with dead fly bodies, which is to guide them out the window. Either open your window a crack and shoo them out, or leave a window open and let them congregate on the screen which you can then lift a few inches and immediately close the window. I was able to dispense with a huge horde of flies in my dining room (ick!) this way without touching the fly swatter.
posted by DrGail at 8:02 AM on August 21, 2024 [1 favorite]

Well, first of all I envy you if "suddenly out of nowhere there are swarms of some goddamn thing?!" is such a rare occurrence that you're freaking out about a random troupe of flies. Live here long enough and I guess you stop noticing that Florida is the insect capital of North America.

Because I do live in a hellish swamp and do not want to spray potent neurotoxins every time I see something sixlegged, I make a thing called Murder Spray, which is rubbing alcohol with Dawn dish soap in it (partly because insects can't deal with soap and partly because Dawn is blue, and that differentiates the Murder Spray from vinegar, which I keep in the same kind of spray bottle and which will not affect insects).

You need a decent spray bottle that will fire a lot of spray, like this thing. Fire it at the fly. Fly will drop like a stone from wherever it is perched or out of whatever airspace it was occupying. Dispose of the fly. Clean up the spray immediately if it gets on the floor and you have slick floors. I've wiped out before. Perhaps the spectacular pratfalls are the wages of sin: all this murder can't be good for the soul. OTOH, I don't care because what else is not good for the soul is swarms of our insect brethren making a nuisance of themselves all the damn time in the house where they do not the hell belong.

There is plenty of fun for insects outside in the yard, and nobody will try to kill them there, so outside is where these little fiends need to stay. Unless you're like a preying mantis or a monarch butterfly, if you cross the threshold, you die, and I am not going to feel any kind of way about it.
posted by Don Pepino at 8:22 AM on August 21, 2024 [4 favorites]

Some kinds of flies will go towards light-- if you wait until dark, turn off all the lights except one in, say, the bathroom, they'll all end up in there and you can spray them in melee range. But not all flies do this, so ymmv
posted by The otter lady at 11:10 AM on August 21, 2024 [1 favorite]

> Cluster flies don't eat dead animals

Blow flies do. OP has a cat. Likely it killed something and hid the remains.
posted by cotton dress sock at 11:36 AM on August 21, 2024 [2 favorites]

When this happens in our house it's 99% of the time because a mouse has died somewhere. We usually see the giant flies before we even smell the thing.
posted by archimago at 12:18 PM on August 21, 2024

Dealing with a live fly is actually less disgusting, I think, than dealing with dead flies. Trap them with something clear and release them outside. (I use a clear plastic or glass jar to trap them, slide something postcard-like over the opening, and then carry them out the door.)
posted by lapis at 3:19 PM on August 21, 2024

Every once in a while a fly swarm happens inside of a human home. It sucks and ...

OMG I just remembered I have another attack-of-the-flies story! We were living in a very weird (likely illegal) basement apartment for a couple weeks while our nearby house was getting the one bathroom gutted and rebuilt. When we got there, there were swarms of houseflies. Vacuum cleaner! Wave that thing around and -whooomp- suddenly a lot less flies. It was noisy, sure, so you don't want to do it late at night, but it did take care of 90% of them easy.
posted by intermod at 8:53 PM on August 21, 2024 [1 favorite]