Water and Flies

Factual Questions
1

Snopes wimped out on this. Anyone know it it works?

Ziplock Bag Good Tip for flies

ZIP LOCK BAG - Good tip!
We went with friends to a restaurant on Sunday for lunch and sat in
the patio section beside the store. We happened to notice zip lock baggies
pinned to a post and a wall. The bags were half filled with water, each
contained 4 pennies, and they were zipped shut. Naturally we were curious!
The owner told us that these baggies kept the flies away! So naturally we
were even more curious! We actually watched some flies come in the open
window, stand around on the window sill, and then fly out again. And there
were no flies in the eating area! This morning I checked this out on Google.
Below are comments on this fly control idea. I’m now a believer!

Zip-lock water bags

#1 Says:
I tried the zip lock bag and pennies this weekend… I have a horse
trailer. The flies were bad while I was camping. I put the baggies with
pennies above the door of the LQ. NOT ONE FLY came in the trailer.
The horse trailer part had many. Not sure why it works but it does!
#2 Says:
Fill a zip lock bag with water and 5 or 6 pennies and hang it in the problem area.
In my case it was a particular window in my home. It had a slight passage way
for insects. Every since I have done that, it has kept flies and wasps away.
Some say that wasps and flies mistake the bag for some other insect nest and
are threatened.
#3 Says:
I swear by the plastic bag of water trick. I have them on porch and
basement. We saw these in Northeast Mo. at an Amish grocery store
& have used them since. They say it works because a fly sees a reflection
& won’t come around.

#4 Says:
Regarding the science behind zip log bags of water? My research found that the
millions of molecules of water presents its own prism effect and given that flies
have a lot of eyes, to them it’s like a zillion disco balls reflecting light, colors and
movement in a dizzying manner. When you figure that flies are prey for many other
bugs, animals, birds, etc., they simply won’t take the risk of being around that much
perceived action. I moved to a rural area and thought these “hillbillies” were just
yanking my city boy chain but I tried it and it worked immediately! We went from
hundreds of flies to seeing the occasional one, but he didn’t hang around long.

2

Here’s an earlier and inconclusive thread on the topic. It references an old SDSAB article that suggests there is some truth to it, but skepticism remained.

3

Someone should do an experiment to see if it works better if Disco music is playing. :slight_smile:

4

Thanks Troutman -
My first post received an answer quickly.
I guess it is time for an experiment. <Makes plans to hang baggies by the back door>
Maybe the average humidity has something to do with if it works or not. I will report back on how it works in Kansas.

5

No. Sorry.
I will not play disco.
Then the flies would be attracted to the involuntary vomit I produced.

6

The Mythbusters busted this myth

7

I’m a skeptic that the bags work, but I don’t think the Mythbusters tested the right thing. Doug on the SDSAB said the bags seemed to work by reflection and focusing of movement and light from the surrounding area. It sounds like the Mythbusters put a bag in a sealed chamber, which doesn’t test this effect all.

8

It seems like a relatively easy experiment to design and implement.
Find two locations that are 50 feet apart from each other and that have lots of flies.
Perhaps, two outbuildings on a farm.
Apply the fly repelling bags to one location (Site A) and not the other (Site B).
Set an observer at each location.
I have found 8 year old children to be useful in this employ especially if ice cream is entered into the equation.
Have the observer count the flies that pass a certain point (as in a doorway or a window).
Record the observations with ambient conditions (time, temperature, relative humidity and barometric pressure at least).
If there is a significant difference between the fly activity at Site A and that at Site B, then move the fly repellent from Site A and place it at Site B in as similar of a manner as it was sited at Site A.
Record fly activity.
If the difference persists, then there may well be some validity to the hypothesis that the pennies in water in ziploc bags are an effective fly repellent.
If so, contact manufacturer of ziploc bags and wait for the royalty checks.
Buy ice cream for observers.