my boss is infesting our office with fruit flies

by Alison Green on March 11, 2014

A reader writes:

I work for a corporation with locations in 63 different cities in the U.S., but I am part of a two-person department. My office and my boss’s office are next to each other, with a door between them, but we do each have our own entrance door.

Our offices have become ground zero for a fruit fly infestation! He likes to have apples, grapes, bananas, etc. at his desk for snacks … which means there are usually a few apples or bananas on a shelf in his office. And remnants in his trash can.

I believe these are the source of the fruit flies, especially since they seem to appear nowhere else aside from our offices. It is 8:30 a.m., I have been at work for only an hour, and have so far killed 7 fruit flies. While I do keep snacks in my storage area, I do not keep fresh fruit or juices.

How can I handle this situation with a boss who is already an avid over sharer with a history of becoming defensive whenever I have tried to politely remove myself from his personal stories (such as health issues for himself or his wife, family tales, whining and griping about tasks assigned from above) and general negativity towards learning new skills or tasks?

Step one is always to politely point the problem out to the other person.

In this case, that would sound like this: “Bob, I’ve noticed we’re getting an infestation of fruit flies. I think they’re being attracted by the fruit on your desk and in the trash.”

Then, if your boss isn’t the type to figure out how to resolve problems of his own making, you can add a suggestion of what to do. For instance: “I think it might help to keep the fruit locked in a drawer and to throw away any leftovers down the hall.”

That’s really the only way to handle this. I understand the hope that there’s some easier way than just being straightforward, particularly with someone with a track record of defensiveness. But with any annoying personal behavior that someone indulges in that you want to stop — whether it’s loud gum-chewing, radio blasting, or taking all calls on speaker phone — you’ve got to just say it. Say it nicely, of course — you don’t need to accuse him of being a filthy slob — but you do need to just say it if you want the problem to go away.

Read an update to this letter here.

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{ 89 comments }

{ 89 comments… read them below }

    1. KC*

      Yes! I had a potted plant I’d brought in to work from home where they were living in the soil. I bought some stuff on Amazon that you sprinkle on the soil and water, and that got rid of the problem.

      1. Mishsmom*

        KC, would you mind sharing exactly what it is? we have the same problem here and nothing i’ve used works…

          1. KC*

            I got it on Amazon and it’s called “Bonide Systemic Houseplant Insect Control.” The bugs it controls for doesn’t specifically mention fruit flies, but it definitely worked for the buggies living in my plants.

            1. KC*

              And now that I’ve seen people’s comments about fungus gnats and I did some Googling about them, I’m fairly sure that my infestation may have been fungus gnats and NOT fruit flies.

              But if it’s possible you’re making a similar mistake about bugs living in your plants, the stuff above really did the trick!

    2. Ellen*

      Fungus gnats can infest potted plants, and are easily mistaken for fruit flies. There’s an easy remedy for them. Add an ounce or two of hydrogen peroxide to a quart of water and water all of your indoor plants with it at the same time, discarding any leftover solution. Repeat for the next 2-3 waterings, and the gnats should be gone.

      1. BadPlanning*

        Is the OPs office like mine where they only take office trash out once a week? Most people throw food trash in the main hallway because that gets taken everyday. Or people dump their small office trash bin in the large office trash bin if they don’t want to wait a week.

        We actually had a company posting about food disposal because people were having fruit fly issues. The solution was don’t throw your food trash in your office trash bin.

        1. Kimberlee, Esq.*

          We have the same issue, only mice are what we try to avoid.

          Honestly, if OP’s boss doesn’t change, she should consider just pulling his garbage each day.

  2. NonProfiter*

    You can easily get rid of fruit flies with a simple fruit fly vinegar trap (Google it).

    1. TL*

      It works okay. Not fantastically.

      (As someone who had a hard time getting used to doing dishes on a consistent basis.)

      1. Meg Murry*

        And only if you get rid of the fruit, plants or other food the fruit flies were living on – they don’t like the vinegar trap nearly as much as actual fruit. So a trap in OPs office might help slightly, but unless she can convince the boss to get rid of the fruit (or at least leave no fruit or peels overnight) it won’t help.

        (As someone who also hates doing dishes regularly and can’t seem to get it together on emptying compost bucket often enough until we get attacked with massive fruit flies.)

    2. Diet Coke Addict*

      Yeah, it works….a bit. I used to work in a tea shop with a horrifying fruit fly infestation, and it trapped a LOT of flies. But very far from All The Flies.

    3. BGirl81*

      I randomly had them in an apartment once and I used sweet white wine to trap ’em. Worked like a charm! You know they were annoying if I was willing to waste perfectly good alcohol on them.

      1. Lanya*

        I’ve tried various forms of alcohol to trap fruit flies at home. Sweet wine was good, also, cherry-flavored whiskey worked like a charm.

  3. pgh_adventurer*

    While you’re working on this, a great way to control fruit flies is through a homemade trap.

    Put some soft fruit in a jar, then set a tightly wound paper cone on top. The flies will fly through the paper funnel and not be able to get out. Once you’ve caught a few, take it outside and let them out.

    I had some fruit flies that were driving me crazy in the kitchen, and this got rid of all of them in 2 days!

    1. Gail L*

      Exactly. It can work with a tablespoon or two of wine as well. And the boss could use it or the OP, depending on how reasonable the boss is.

      2. Stephanie*

        I had a box of the “Chillable Red” flavor of Franzia. The fruit flies looooooved that when I put some in a bowl.

        And yeah, turns out our fruit flies were coming from my roommate’s plants. She had overwatered them and the soil was damp.

    2. Jamie*

      I have a similar method that works beautifully.

      Vingear in a bowl with a tbls of sugar and a squirt of dish soap. Cover with plastic wrap and cut some slits in the top. They gets in, the soap traps them…then just dump it out when they are all in there.

      Works like a charm.

        1. monologue*

          cider vinegar is the best. I had a bad infestation once so I messed around with a lot of different kinds of traps.

          Also for really bad infestations, don’t wait for them to get trapped, vacuum them up and set a trap for the ones you missed. I also started keeping my compost in the freezer during the hotter months.

        2. A Bug!*

          Me too. I use a small glass container that’s wider than it is tall, with an inward-curling lip. A shallow layer of apple cider vinegar and a drop of dish soap, and by morning I’ve got pretty much every fruit fly in the house. Provided the source is taken care of.

    3. AMG*

      Yep, I have seen this and they absolutely gravitate to the trap. Works so well. Also, spraying plants with a bottle of water that has one drop of dish soap in it. The soap won’t hurt the plants and the bugs hate it.

  4. Just a Reader*

    Gross.

    And you shouldn’t have to do this, but a cup of apple cider vinegar with a few drops of dish soap, covered in saran wrap with holes punched in it, will capture the flies overnight if you’re tired of swatting.

    Not the answer you were looking for but it will help.

  5. EM*

    Are you sure it is his fruit?

    I had this in my previous office and it wasn’t because people had fruit — the flies had totally taken over the numerous potted plants in the office that our Director liked to keep around.

    It was SUPER annoying, however — you have my sympathy.

  6. Celeste*

    We had them from a boss’s plants. I’ve heard that the vinegar traps work quickly and efficiently.

    But do something before the population gets bigger, because it’s horrid to see them land in your fresh coffee.

    Fruit should be stored in a lunch box if there is no refrigerator. Beware of trashing the peels and cores and in receptacles that aren’t emptied every day. Our place has cut back on janitorial, and now it makes sense to pack out food waste or put it in the break room trash–not just for bug control but odor control.

    1. some1*

      I live alone and don’t have the need to take my trash out more than once a week. When I have fruit peels/cores I put them in a ziploc bag in the freezer until my trash is full and ready to go out — so this can work for places that don’t empty the trash everyday.

      1. MJH*

        YES! My family always did this, too, with smelly food trash. No one else seems to, but it works really well.

        1. Aunt Vixen*

          I don’t do that with fruit leavings, but with meat trimmings it is a must. Nothing stinks up a kitchen faster than chicken parts.

          1. danr*

            Putting the plastic bag in the freezer eliminates the smells. Then you just have to remember to throw out the stuff on trash day.

          2. tcookson*

            This is going to revolutionize my chicken-cooking! For the past few years I’ve made Monday chicken-cooking day, because Tuesday is trash pick-up day. Now there’s no telling what day I might cook a chicken!

      2. Celeste*

        Yes, that’s smart. Some of it can go down a disposal if you have one, but other things are too fibrous.

      3. Cath@VWXYNot?*

        Same here, except I use a compostable paper bag with wax lining, and once it’s full the whole thing can go straight into the city green bin or my own compost bin.

      4. LCL*

        This also works for meat based scraps and packaging, if I am not going to take out the trash that night. Because if left in the trash, it drives the dog insane, he will sit and stare at the trash can cupboard and whine.

  7. Anonymous*

    I used to have a ton of fruit flies – left a tassimo latte out on the table and literally within an hour every fruit fly was drowned in that cup.

    1. LMW*

      Through a similar accidental experiment I found that almost empty wine bottles work very very well on fruit flies too.

      1. tcookson*

        Through trying to drink a glass of wine in peace, I’ve learned that every fruit fly in the whole house will drown in your wine glass if you set it down for even a minute. I’ve started putting a small saucer on top of my glass in the hot months.

  8. Stephanie*

    Ha, I came here to post about a vinegar trap and that it might be from potted plants….and everyone beat me to the punch.

    I got a sad text from my roommate once: “Work confiscated all our plants because of insect concerns. That was the only source of color in my cube. :(“

        1. Stephanie*

          Her office held them in a loading dock (?) for a bit. Eventually, everyone got his plants back.

  9. Stephanie*

    Oh, be sure to cover the drain up in the kitchen. I’d also pour some bleach down the drain to kill any larvae. Fruit flies like to lay eggs in sink drains.

    3. Rayner*

      I would also do a baking soda and vinegar bomb down the drain as well, to make sure that they’re not hiding in nooks and crannies around the rim and such. Just need cheap white vinegar and baking soda, you can do the whole thing for about three bucks or less in the UK, so…

      2. Christine*

        DO NOT allow the vinegar and bleach to mix, or allow bleach to combine with anything acidic – it will make
        chlorine gas, which is toxic. Do one, rinse a lot, then do the other.

    4. B5SnowDog*

      Yeah, I was going to mention the drains. Pouring boiling water down the drains works well if you don’t have bleach on hand or can’t/don’t like to use it.

  10. Diet Coke Addict*

    I used to work at a tea shop with a disgusting fruit fly infestation. We tried everything–the vinegar traps, the dish soap traps, bleaching the drains, bleaching the floor drains, keeping everything in airtight containers, etc. Unfortunately just keeping the fruit locked in a drawer probably won’t help–unless they’re in an airtight Tupperware.

    If the infestation gets too bad you may have to eventually end up calling an exterminator to eliminate it. Fruit flies are awful once they get to be at true infestation levels and are nearly impossible to eradicate. (But this is at the serious infestation level, not “there are some in my office.” ) But airtight containers, throwing away the garbage outside if possible, and cleaning and bleaching all surfaces including any drains will be a good start and might be enough to fix it.

    1. Paige Turner*

      Yep, when I worked at a coffee shop they would live in the floor drains and if we didn’t clean the drains a couple times a week, it could get out of control really fast. The exterminator and the wet-dry vac were my friends :/

  11. Leah*

    “whether it’s loud gum-chewing, radio blasting, or taking all calls on speaker phone”

    I had a co-worker who was all of these. She would also show up as she pleased and not really do work. She got away with this because she had a bunch of sick leave and vacation time banked from the previous 20+ years and was about to retire. I got stuck doing her work along with my own. If she wasn’t working, how could she have been taking calls on speakerphone? They were personal calls.

  13. DM*

    My office has mice – our admin team pretty regularly reminds us at staff meetings on how to minimize the issue – don’t leave food in our offices overnight and use the kitchen trash can for all food waste. Seems to be well received coming from them as a reminder to the whole office (though I don’t think our issue could be blamed on any individuals)

    1. AnotherAlison*

      I *thought* my office had mice once. Until I realized the violated bag of candy had been violated at my house, before I brought it to work. The house was a p.o.s. rental with a cinder block foundation, backed up to an empty field. Mice ran wild in our walls. The office was a nice 7 story building. It took me surprising long to figure it out.

    2. Stephanie*

      Ugh, we had roaches at OldJob’s kitchen. I think a lot of the issue was that we had no eating area, so everyone ate lunch all over the office.

      1. Audiophile*

        Ewwwwwwwwwwwwwwwwwwwwwwwwwwwwww!

        The office I work in recently went “green” and had to send an office-wide email to say people needed to be mindful not to leave dishes in unapproved places. People were leaving dishes at their desks, in offices, even though there are two tubs in each pantry area for dishes and utensils. And the kitchen staff collects all these items before the end of the day.

  14. KC*

    It’s as if by the very mention of fruit flies on this blog, my office has grown some. I just saw a singular fruit fly buzz past my computer screen.

  15. Allison*

    We had a HORRID fruit fly infestation at my office last year. Like, I had to stop eating in the office and could only drink out of covered glasses. Turned out someone was composting the office’s used coffee grounds in the kitchen, under the sink, and had been for months without anyone knowing about it.

    1. A Bug!*

      Good idea, terrible execution. Inconsiderate in the main to do it at work, especially without approval. And fruit flies are a sign of an unhealthy compost to boot.

      As a casual composter, I’m curious: was it just a bucket under the sink or something? What kind of stuff was going into it other than the coffee grounds?

  16. Rin*

    I think I may be misinterpreting Alison’s answer, but this isn’t just an annoying personal behavior. This is disgusting, and this needs to stop. I remember a writer a while ago who had bed bugs and everyone thought it was so gross. Isn’t this just as bad?

      1. A Bug!*

        Yup.

        Fruit flies are gross, yeah. But they’re really not that big a deal in the grand scheme of things. OP’s not in danger of bringing home an infestation. They don’t feed on humans, they’re easy to avoid in general and usually easy to treat when you can’t. Since they feed on and reproduce in fruit, it’s a simple matter to remove the fruit and take out the garbage before setting a trap to catch whatever’s left.

        Bed bugs, on the other hand, are actual, literal monsters. They feed on humans. They can go months without a food source. They live and reproduce in pretty much any soft material that places them near a food source. It’s difficult to spot bedbugs before an infestation has taken hold, and once it does, it spreads easily and is extremely difficult and costly to fully eliminate, even by professionals.

  17. Cath@VWXYNot?*

    I once worked in a place with the opposite problem – all the fruit flies in the genetics lab were dying, and no-one knew why! The mystery was finally solved a couple of months in when someone realised that the deaths started the same week as the new smoking by-law, and the smokers had moved from near the front door to an area further away… right by the air intake for the fly lab. Ah, science!

    (I’m not advocating filling your office with cigarette smoke, by the way. Smoke is way worse than flies!)

    1. Anonymous*

      Mystery solved. This is probably why my mother (a smoking enthusiast) can leave fruit out on the counter all the time and never, ever get fruit flies.

  18. Anonymous*

    I can’t bring plants to work because they will get infested with fungus gnats. I’m not sure where the infestation is coming from, though! I have no fungus gnats at home, but every plant I bring into work eventually becomes a fungus gnat breeding ground. WTH. I’ve considered some sort of covert plant investigation to find the source, but I’m too busy / lazy to bother.

    1. Dan*

      “LOCKED”?

      Presumably because fruit flies don’t have opposable thumbs and can’t use keys. O_0

  20. Mochafrap512*

    as for your office, I would get something to catch them. At my house, we have these small, apple shaped jars that have liquid in them. The fruit flies are attracted to the liquid, go inside, but are then trapped And can’t get out. I will find our where to get them and post back later.

  21. Stephanie*

    Anyone have suggestions on how to catch actual flies? We live near a lot of cattle and horse farms and the flies can get out of control (and are starting to again with the warmer weather). Best thing I’ve found is fly paper, unfortunately (it just gets gross).

    1. Rayner*

      You can buy little fly stickies which emit an odor that flies like, but once they walk across it, they die.

      I would suggest also putting up voiles, or screens, if you have them, as they can improve the fly condition. We lived in cow country for a while.

      And just make sure everything is SUPER clean. They’re attracted to rubbish, left out food, even sticky residue on work tops.

    2. tcookson*

      I had a hanging fly trap last summer; it was a cylinder of cardboard coated in a sticky substance that the flies would get trapped in. It had black ink-drawings of different-sized flies on it, so it took me a while to notice when some actual flies were caught. It was a nice camouflage that the caught flies looked just like the printed-on flies; it seemed less disgusting that way.

  22. Anonymous*

    Can I suggest if it is the bin waste that you approach the boss about getting a ‘food waste’ bin – a small pedal bin like the one in most peoples bathrooms that is closed all of the time?

  23. T*

    The bakery of the grocery store where I used to work put peppermint extract on a paper towel and set it near the fresh bread. This acted as a repellent to keep fruit flies away from the bread. In your case, it would not rid you of the flies, but at least you could keep them away from your desk.

  24. Rayne (OP)*

    Our office is far enough away from the kitchen that I can reliably say the fruit flies don’t come from there. And our adjoining offices don’t have plants, so although there are plants down the hall, I doubt seriously that these are gnats living in the plants. If so, I would expect to find bugs buzzing the people who do have plants.

    I approached him about the fruit flies yesterday afternoon, and I can’t say it went well. Technically company policy forbids any food or snack items stored in offices that do not come in sealed packages.
    I used Allison’s wording exactly, only changing the name to fit my boss. I got a very dirty look but no actual response. I did notice later that he had a clipboard over the fruit bowl, I suppose in order to contain the flies somehow……but the clipboard doesn’t fully cover the bowl.

    I will be looking into vinegar traps I can somehow disguise as decoration or air freshener!

    The VP is coming to our office on Friday morning for unrelated purposes, so perhaps his notice of the fruit flies will prompt some further action.

  25. JJ*

    I had coworker bring fleas to the office and my boss refused to deal with it because her office was too far away to be bitten by them-(she didn’t want to embarrass anyone) so, i resorted to bringing in huge cans of spray and bombing our cubes myself. The woman who brought the fleas to the office knew it was her, she said she had fleas at home several times, and yet pretended that she didn’t know about them when i wound up spraying. it was gross to say the least!

  26. Joe Schmoe*

    You can add a little dish soap to the water that you water plants with, and that’s supposed to help control the flies.

    Another trap (mind you I haven’t read all the comments yet) is to put about an inch of dish soap (Dawn, etc) in a small container and then pour some apple cider vinegar on top (about 1/4 inch). The vinegar attracts them, and the dish soap traps them.

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