The idea is simple. Yeast feeding on sugar gives off carbon dioxide, the same gas we breathe out, and mosquitoes follow it. So a bottle of sugar, water and yeast should lure them in. It does catch some. It just isn’t the whole answer.
How to Make It
- 1 plastic bottle (2 liter), cut one third down from the top
- 1 cup warm water
- 1/4 cup brown sugar
- 1 teaspoon dry yeast
- A splash of dish soap
Dissolve the sugar in the warm water and pour it into the bottom of the bottle. Sprinkle the yeast on top; don’t stir. Add the dish soap. Turn the top of the bottle upside down into the base as a funnel. Wrap the bottle in dark paper or cloth; mosquitoes like shade.
Set it in a shady corner of the yard, away from where you sit. Refresh it every two weeks.
What to Expect
Be honest with yourself here: these traps catch a small number of mosquitoes and plenty of other small insects. Field tests of yeast traps have had mixed results. A trap alone won’t clear a yard.
What Makes a Bigger Difference
- Dump standing water every week. Plant saucers, buckets, toys, gutters, bird baths. Mosquitoes need only a bottle cap of water to breed.
- Run a fan on the porch. Mosquitoes are weak fliers and a steady breeze keeps them off.
- Change bird bath water every few days.
- Use a repellent with DEET, picaridin or oil of lemon eucalyptus when you’re outside at dusk.
- Fix window screens.
Frequently Asked Questions
Why brown sugar?
Any sugar feeds the yeast. Brown sugar is what most recipes use.
Is it safe for pets?
Yes, but keep it where it can’t be tipped over.
When are mosquitoes worst?
At dawn and dusk, and after several days of rain.
