What are these jumping flies?
September 9, 2009 9:42 AM   Subscribe

Fly identification question: we've got little black flies hanging around our fridge, garbage, and sink drain. Don't think they're drain flies because they don't have furry wings. They hop when you try to smack them.

We've tried pouring bleach and hot water down the sink, keeping dishes clean, taking out the trash more often, without luck. Any trapping / killing ideas are welcome, but mostly I want to know what I'm dealing with first. Thanks in advance.
posted by miniminimarket to Home & Garden (10 answers total) 2 users marked this as a favorite
Do they try to fly at all? If they just hop, they're not actually flies. I think we need a better description.

Anyway I've got some pretty good experience with this.

1. First off, see if they respond to fruity decay stuff. Set out a cup, or better yet, a cup with a funnel on top, filled halfway with cider vinegar. If they swarm to it over the following hour, then ouila, this is your trap.

2. If they don't respond to it, you have something different. Back in June we had jumpy gnat like things around the sinks that didn't care for the vinegar traps. I was almost sure they were some sort of fruit fly, but they weren't. At night they would hover near the computer screens like little mosquitoes. I eventually found that they were ONLY attracted to bright things during the day (sink) and to lights at night. I trapped them at night by turning on a single bright light bulb in the house and vacuuming them up in multiple stages. Eventually that got rid of them. So you may want to see if they like light.

Hopefully that helps.
posted by crapmatic at 9:48 AM on September 9, 2009

My guess (without having seen them) would be fruit flies. I would try the vinegar trap, but add a few drops of washing-up liquid or similar to break the surface tension. It might not completely irradicate the problem but will probably get a lot of them drowned. Also check that you don't have rotting fruit or other things lying around which they might enjoy.

It might also be that they're living in/around any plants you might have in the house, so check there as well.
posted by bjrn at 9:51 AM on September 9, 2009 [1 favorite]

They do fly, and they look bigger than fruit flies. They seem to zig zag across surfaces, or hop (they move so fast it's hard to tell). They didn't seem particularly interested in the bananas we had out, but I accidentally left old some iced coffee (with splenda, not sugar) in a plastic cup on the counter, and there were about 10 of them floating in it when I got home yesterday. Hope that helps.
posted by miniminimarket at 9:56 AM on September 9, 2009

Could they be fungus gnats? Do you have houseplants or potting soil around? Check the dirt. I used to have a similar problem, and it turned out they were laying eggs in my plants and in my bag of potting soil. Once I changed the dirt, the problem was gone.

I keep a few Nepenthes plants around the house, too, which also help control the fly & gnat population.
posted by katillathehun at 10:15 AM on September 9, 2009

Hmm, just saw your mention that they're bigger than fruit flies, so they probably aren't fungus gnats. Nevertheless - if they're attracted to coffee grounds, they might still be the sort of flies who like soil. If you've got any, check it for flies.
posted by katillathehun at 10:17 AM on September 9, 2009

Also check that you don't have rotting fruit or other things lying around which they might enjoy.

Yeah, flies only have a life cycle of around a week or so, so if you have significant numbers of them around for a decent amount of time that means there's a good chance that they are breeding somewhere in your house. I learned this one the hard way; there were a smallish number of fruit flies flying around for a few days even though I didn't have any food lying out and I took out the garbage, and it turned out that there were a few rotten potatoes up on a high shelf in a kitchen cabinet that I forgotten about. If you really get rid of everything that the flies can eat and lay their eggs in, they will be gone in a few days.
posted by burnmp3s at 10:17 AM on September 9, 2009

Small, fruit-fly-sized flies that hop are Phorid Flies (aka Humpbacked Flies). They feed on all kinds of decaying organic material, not just fruit. Take a look at the pipes below your sink to see if there's any gunk there. You could also try pouring boiling water down your pipes to eliminate organic material there.
posted by Coffeemate at 10:29 AM on September 9, 2009

Can't help you with identifying them, but I had great success killing little black flying things in my kitchen with this:

posted by geekchic at 11:12 AM on September 9, 2009

A good vacuum with the narrow crevice tool nozzle.
posted by weapons-grade pandemonium at 11:37 AM on September 9, 2009

Coffeemate was right. After I read his answer I vaguely remembered my boyfriend putting a bag of potatoes on top of our kitchen cabinets, which extend to the ceiling practically. He just threw them away while urging me to stay in the bathroom. The smell, oh the smell.
posted by miniminimarket at 7:01 PM on September 9, 2009 [1 favorite]

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