Here is a very inexpensive but very effective trap for catching and killing mosquitoes without chemicals.
– Cut the top off a plastic bottle.
– Melt 100g of sugar in lukewarm water.
– Pour the mixture into the lower part of the bottle.
– Add a tablespoon of baker’s yeast (the water should be barely lukewarm).
– Place the other part of the bottle on top, neck down.
– Cover the sides with cardboard or a black garbage bag (mosquitoes like to lay eggs in dark places) and place your trap where you want it.
The baker’s yeast will release carbon dioxide which will attract mosquitoes into the trap. They will find themselves stuck in the lower part of the trap.