Q. I was at a child’s birthday party and wasps and bees were flying all over while the food was out. Someone said to get self-sealing plastic bags (sandwich size is fine), fill them with water and put them on the table. The wasps disappeared. If I hadn’t seen this with my own eyes I never would have believed it.

I went to another party and the host had put plastic bags of water all along her deck and anywhere people were sitting. There were no bees or wasps and she lives out in the country.

Apparently the light reflecting on the bags of water hurts their eyes. This is a cheap way to keep the stinging bugs away without the use of chemicals.

A. Thanks so much for this fascinating tip. We could find no scientific studies to support this approach, but that doesn’t mean it won’t work.

Some folks say that the same trick (with partially filled gallon-sized zippered plastic bags) may work to keep flies away, while others maintain it is an urban legend. Since it is really cheap and risk free, we see no problem in giving this approach a try.

Photograph note: The setup in the photograph did not keep wasps and yellowjackets away from the hummingbird feeder.

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  1. JimT

    It seems to work! On our front porch, we are always pestered with wasps and/or hornets.
    A couple of weeks ago, my wife heard about this concept…several pennies in a zip-lock bag with water. I said “are you kidding me?” But we gave it a try anyhow, putting the bag on the railing…sure enough, no more pests.
    Two days ago, as a test, she took the bag inside and guess what? Within a few minutes, a wasp pestered us. Put the bag back out…no more pests!

  2. brian flanagan

    Love the comments about plastic bags, any more info out there, am more interested in getting wasps out of my garden and patio area, thnks

  3. MarshaFaith

    If u put 1/2 cup of lemon juice in half gallon an fill remaining with water an spray all around but not on feeder.. has worked for me.. Hope works for all of you… Blessings,

  4. Sweetp

    Joe, in response to your comment, I believe your experiment failed because of the way you displayed the water filled bags. The best way to repel flying insects is to hang the bags above a door, the post of your porch or from the inside of the porch. I tried this last summer to get rid of flies and it worked. This year there were so many wasp flying around my porch and I couldn’t understand why so many this year as oppose to last year. It was until someone reminded me to hang the bags of water and this time place penny into each one. OMG!!! It worked!! It really worked!! How could I be so absent minded. I’ve been sitting on my porch for about 2 hours so far today and have had no visitors from wasp. Before hanging the bags I was running in and out of the house fearful that I would get stung. This works!! Try it again but hang the bags this time.

  5. Gerald J.

    Mrs. McWashington in Meehan Junction, Mississippi has some of the finest BBQ you can get in the South. Outside and right next to her screen door entrance, she hangs a quart freezer bag half full of water. When I asked her about that, she said it was to keep the flies away. I thought she was crazy but I asked her how that would work. She said that, to the flies, it looked like a hornet’s nest, and that they avoided it because of that. Now that’s backwoods wisdom! I have eaten with her a half dozen times, and only once was there just one fly bothering my beans.

  6. Alethea

    I’ve seen this work in restaurants, but the pennies inside the closed ziploc bag full of water make it work. The pennies reflect light (and we were not in direct sunlight, but there were still no flies). We asked the manager, and he said the reflection of the pennies, distorted thru the water, disorients the insects. I guess their visual senses are more heightened than humans’.

  7. Chuck B.

    To me the reflection of the insects off the bags is what it is all about. They see another insect maybe larger in size then they and shy away. Just my theory.

  8. DH

    Could it have anything to do with what the bags are resting upon? and therefore, what the wasps see through them? I’ve heard of people hanging them as opposed to laying them out. Just wondering.

  9. Bill

    I tried the plastic water filled storage bag “trick” but added three pennies. It was hung from my porch roof to ward off bumble bees which had made a nest under the deck. It worked and there are no bees. It has something to do with sunlight and a prism effect on an insect’s compound eyes.

  10. SH

    I’ve never heard of just laying the bags on the railing like that. And I haven’t heard of this deterring wasps.
    I can tell you that hanging them is a good fly deterrent. An ingenious idea from Mexico.
    I learned this from Mexican Restaurants that have an outdoor covered patio–where I live, they almost always have them hanging around the edge of the patio (from the eaves). They’re hardly noticeable–I never noticed them til someone told me, then I noticed them everywhere.
    They use a quart-size zip bag, filled about 3/4 full of water. They hang them I’d say every 8 feet or so around the perimeter. They say the flies see themselves magnified or something, and stay away.
    They do stay away.

  11. Joe Graeden

    This comment came from a reader in response to the Q&A above. It is her picture that demonstrates her experiment:
    Your column in today’s paper included a tip about using water-filled plastic bags to deter stinging insects. I’ve had a problem with yellow jackets & wasps around my hummingbird feeder all summer. So this morning, I filled 2 large plastic bags bags with water and laid them on the porch railing, directly under the feeder (very close to the bottom of the feeder – maybe 4-6″ separating them). I then watched the scene for the next 4 hours.
    My “scientific” report is that the bags did NOT deter the insects AT ALL. The bags were in shade when I started the experiment, and now they’re in full glaring sun. So “light” doesn’t seem to have anything to do with the bag theory.
    I’ve seen numerous yellow jackets & wasps landing on the feeder all day, as usual. In fact, one wasp even sat on top of one of the water-filled plastic bags for a moment. The insects do not seem confused at all — they are finding the openings of the hummingbird feeder with no problem, as usual.
    I have digital pictures showing this FAILED experiment, so as Dave Barry would say, “I’m not making this up.” Based on what I saw today, I would not rely on water-filled bags to protect any human at any outdoor function. I’ll be interested to see if anyone else repeats this experiment and what their results are.

  12. anonymous

    The information from a reader regarding the use of a water bag to repel wasps that you reported in a recent column was very interesting. Should the bag be closed or sealed? If sealed, how does this work… if not, why doesn’t the water run out?
    We enjoy your column.

    • Sandy
      Stone Lake, WI

      Take 1 qt zip lock bags, fill 3/4 with water, add 6-8 shiny pennies and seal the bag. The coins must be shiny and the bag must be sealed. Hang the bags, do not lay them around where you see wasps , hornets, flies, etc. I use old metal shower curtain hooks poked through the thickest upper part of the sealed bag. Do not puncture the lower part where the water is located. Mine are hung by the hummingbird feeders and the hornets are gone. Works for me.

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