I was in Nicaragua recently and noted many restaurants and convenience stores had small sandwich sized bags filled with water hanging at their entrances. When I asked why, they said it was to repel mosquitoes.
This seemed to be a widely held belief even extending to other countries in Central America.
I have not found a reliable source claiming that bags filled with water can repel mosquitoes, but I hope that these sites can help to corroborate what I personally noted.
- Plastic bags of water as mosquito repellent - JREF Forum
- Banish mosquitoes naturally on the cheap - DIY Life
- That hanging plastic bags filled with water will repel Mosquitoes
I am aware that the more common claim seems to be about flies and that this was busted on an episode of MythBusters. It is the claim that bags of water can repel mosquitoes which interests me however, given how common it was in some parts of Central America.