My neighbor very kindly gave me a fly trap a few weeks ago, and I totally forgot about it. Last weekend I set it up. Check it out.
These traps are very simple. Just a bag with a plastic top you pull out. Fill it about half-way with water, hang it up, and there you go.
There is some kind of attractant inside that I assume is water-soluble, and it doesn`t smell so great.
The idea was to keep flies from bothering me while relaxing on my porch. I made the mistake of putting the trap near where I sit, thinking it would keep them away.
Well... it did... sort of. There weren`t flies on ME, per se, but there was always a cloud of buzzing pests orbiting the bag during daylight hours.
I believe this thing was drawing insects from all over the neighborhood. So, I moved it away from me and let it do what it does for a few days.
Within a week it was full of dead or dying flies and other bugs like wasps. Eww. It works... if you use it properly.