I have a Mosquito trap by Flowtron. I've had it for three years now and it has done a great job. Like EricF the first year it trapped the most and then less each year. However, we have noticed less and less mosquito's in the yard.

According to the literature that came with the Flowtron, mosquito's are fairly territorial, meaning they do not travel more than several hundred yards from their home. Also the female mosquito's are the ones that bite. Therefore, over a period of time, you reduce the female population in a given area and subsequently reduce the overall mosquito population.

The placement of the trap is also critical to it's effectiveness. It needs to be placed between the mosquito's home (woods, pond, etc.) and the food supply (you). It should also be placed such that it is up wind from the home. The theory is the mosquitos can fly against the wind before feeding and use the wind to glide home once they are full.

I'm not sure how valid any of these theories are. I only know we can sit outside at night without getting eaten alive.