Alternatives to pesticides

On my way to work on Friday, I stopped in at a gas station / diner that is down the road from my work for a quick 560 calorie bacon egg and cheese biscuit, and as I entered, I saw this:

It is a Ziploc bag of water with a penny inside, and it is nailed to wall by the front door of the restaurant.  My mind immediately began inventing possible explanations:  Did a customer leave this behind and the proprietor, being a good Samaritan, hang the bag so that it could be returned to the rightful owner?  Was some kid doing a science project about pennies and their resistance to corrosion?  Was this some sort of miniature wishing well that patrons could somehow drop pennies in?  Was this a urine sample left by one of the workers (who had drank enough liquids to make their urine clear) for their parole officer to pick up?

I could not work it out in my mind, so as I sat at the stainless-steel counter waiting for the cook to make my biscuit, I asked the girl behind the counter what the bag of water was for.  Flies, she replied.

I obviously had a puzzled look on my face because she went on to say that the bag keeps the flies away.  What is in the bag, I asked, wondering if there was some chemical that could somehow permeate the plastic bag and repel insects.  Her reply confirmed what I suspected.  Nothing but water and a penny, she said.  It works.  You don’t see any flies around here, do you?

How exactly does it keep the flies away, I queried.  Her reply was even more bewildering: They see themselves in the reflection of the penny, which makes them look larger than they really are and they are scared away.  I asked her if she was pulling my leg.  She answered me by calling one of her co-workers over to corroborate.  Sally, a middle-aged woman came from the back and told me that the bag was to repel flies, but that it was the glare from the sun that repelled them, not their own reflection.  Sally also asked me if I saw any flies around, and I admitted that I did not.  I had the sense to not point out that it was mid-January, which isn’t exactly fly season, even in southern Mississippi.

Another patron also had some wisdom to add: Them mosquitoes must be blind then, cause they come in here all the time in the summer.

Don’t be surprised if you see a Ziploc bag nailed to my patio door.  After all, if it works in January at that restaurant think how great it will be in June when I am grilling burgers on the deck!