Using the knife, cut the top of the bottle just below the area where the neck of the bottle runs out to connect to the main body of the bottle.

Once you’ve cut the top of the bottle off, you’ll have two pieces that can be rearranged to create the trap: the bottom cylinder and the neck of the bottle.

Remove the cap from the neck of the bottle. Turn the neck of the bottle upside down and insert it into the cylinder like a funnel.

Don’t push the funnel all the way to the bottom of the bottle. Leave enough room between the neck of the bottle and the bottom to add about a cup of liquid and an air space between the surface of the liquid and the lowest point of the funnel.

Use tape to secure the funnel. The tape not only holds the funnel in place, but it also seals the edges of the funnel to the edges of the bottle. This will make it harder for insects that get into the mosquito trap to

Add 1/4 cup brown sugar to 1 cup boiling water. Mix well until the sugar is completely dissolved.

Let the mixture cool to 122°F. Be careful, if it’s too hot, the high temperature will kill the yeast. If it’s too cold, the yeast won’t activate fully.

When the sugar mixture has reached the right temperature, gently stir in the yeast. Pour the mixture into the bottle (the inverted funnel makes this easy) and the mosquito trap is ready.

How it works:
The yeast and brown sugar create a stream of carbon dioxide that attracts insects into the trap. The hungry mosquitoes follow the trail in the bottle and descend through the funnel. When they realize there is no food, they fly along the surface of the brown sugar mass until they reach the sides of the bottle. The insects then fly to the side of the bottle, but their escape is blocked by the tipped over funnel (hence the reason for sealing the edges with tape). The little insects are trapped!

Mosquitoes get tired and fall into the liquid to drown. Sure, a few lucky mosquitoes may squirm their way through the narrow funnel entrance to freedom (and bite again another day), but most insects that get into the trap die there.