My yard gets overrun by mosquitoes every summer, due to there being a lot of woods and sitting water areas in the neighborhood. Unfortunately, many of these areas are outside of my yard, and/or protected, so I can't do anything about them. It gets so bad that I can't let my little girls play outside, as they'll instantly get assaulted.

Last summer I purchased a Flowtron bug zapper that claimed to cover an acre and a half. It did nothing (even with the mosquito scent packs), which is no surprise after the research I've done since then on how worthless bug zappers are for killing biting mosquitoes. Apparently they're attracted to very slight levels of CO2, however the CO2-based mosquito traps on the market seem to all get really bad reviews, stating that they do the job well when they work, but that they often break down. Since most of them are very expensive, this doesn't seem like a good option to pursue.

I was wondering if there is some sort of simple device that can emit CO2 very slowly, and that I can place right by my bug zapper. Draw them in with the CO2 and then ZAP!! I'm not the most handy person in the world, can anyone think of a way that this could work?

3 Answers 3


You can generate CO2 with a mixture of yeast, sugar and water, and there is scientific evidence for its effectiveness in attracting mosquitoes. Saitoh et al. (2004) tested the apparatus shown below.

Yeast mosquito trap

They constructed it as follows:

Two plastic bottles (2-liter volume) were used to hold water solutions of sugar and yeast. The 2 bottles contained different concentrations of dry yeast and sugar: bottle A, 150 g of sugar + 12 g of dry yeast, and water added to total a volume of 1,500 ml; in bottle B, 100 g of sugar + 6 g of dry yeast, and water added to total a volume of 1,750 ml. Because bottle A contains a larger amount of dry yeast, the output rate of CO2 is higher and the length of supply period is shorter than in bottle B. By using the 2-bottle system, we could achieve the high output rate of CO2 as well as the long supply period. The bottles were connected to each other with polypropylene tubing and to a small (500-ml-volume) plastic bottle holding the overflowed water solution. Generated CO2 was released from a 5-mm hole on the outer wall of the small bottle. For easy preparation of the water solution as well as cleaning, there were 3 joints in the connection tubing (Fig. l). The small bottle was hung close to the opening of a suction trap, similar in design to the CDC-light trap (Service 1993). It was made of 14-cm-long acrylic tubing with an inside diameter of 8.5 cm attached to a 3.0-V motor driving a three-bladed plastic fan powered by four 1.5-V dry batteries.

You can of course omit the suction trap and just hang the CO2 emitter near your existing trap, if you have one.

The abstract summarizes the results:

The system could, at average, generate 32.4 ml/min of CO2 for at least 27 h. The total weight of the CO2 generated was estimated to be 94 g. The efficacy of yeast-generated CO2 as attractant for mosquitoes was significant, and the following 6 mosquito species were collected using yeast-generated CO2 traps from July to September 2003 in a residential area of southern and northern Yokohama City, Japan: Aedes albopictus (Skuse), Armigeres subalbatus (Coquillett), Culex halifaxii Theobald, Cx. pipiens pallens Coquillett, Ochlerotatus japonicus (Theobald), and Tripteroides bambusa (Yamada). Besides mosquitoes, various other insects were collected in the trap.

(My emphasis.)

Smallegange et al. (2010) used a similar yeast system and found:

Traps baited with yeast-produced CO2 caught significantly more mosquitoes than unbaited traps (up to 34 h post mixing the ingredients) and also significantly more than traps baited with industrial CO2, both in the laboratory and semi-field. Adding yeast-produced CO2 to traps baited with human odour significantly increased trap catches. In the MalariaSphere, outdoor traps baited with yeast-produced or industrial CO2 + human odour reduced house entry of mosquitoes with a human host sleeping under a bed net indoors.

(My emphasis.)


Saitoh, Y., Hattori, J., Chinone, S., Nihei, N., Tsuda, Y., Kurahashi, H., & Kobayashi, M. (2004). Yeast-generated CO2 as a convenient source of carbon dioxide for adult mosquito sampling. Journal of the American Mosquito Control Association, 20(3), 261–264.

Smallegange, R. C., Schmied, W. H., van Roey, K. J., Verhulst, N. O., Spitzen, J., Mukabana, W. R., & Takken, W. (2010). Sugar-fermenting yeast as an organic source of carbon dioxide to attract the malaria mosquito Anopheles gambiae. Malaria journal, 9(1), 292.

  • It'd be really good if you provided details/description of the apparatus. What happens at the "joints", What is a "suction trap", etc.
    – Martin F
    Commented Apr 17, 2017 at 18:05
  • @MartinF Thanks for the suggestion. I've copied in the details from the paper's methods section.
    – Pont
    Commented Apr 17, 2017 at 18:51
  • 2
    If you're going to do all this, you might as well try to make beer :-)
    – Pepi
    Commented Apr 20, 2017 at 6:57

Burn an ordinary paraffin candle.

There are several claims floating around that describe how some well-intentioned people are actually increasing their total CO2 emissions, by turning off their electric lights in favor of burning candles.

As most of these articles are politically motivated, it is hard to find neutral and scientifically sound sources. What is clear is that burning candles definitely do emit CO2; how this compares to an electric bulb gets lost in the rhetoric.

I will refer you to our partners over at Skeptics SE, who have a thread about this topic.


In the Philippines. A 1 litter bottle. Cut of top, insert in bottle. Like a funnel. Sugar water a pinch of yeast does work. Or set near light zapper. So very cheap to make. Mint oil. Contact with mint oil is deadly to all mosquitoes. So they avoid that sent. A oil lamp with mint oil burning will repel mosquitoes. What I use in the Philippines when setting out on the porch at night. Set the oil lamp near the ground slightly upwind.

  • Thanks, I'm going to try this, as it's simple enough that even I can do it!
    – Justin
    Commented Apr 18, 2017 at 1:45
  • 1
    By "mint oil", do you mean an essential oil like peppermint? Or something else?
    – Justin
    Commented Apr 18, 2017 at 1:46

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