University of Wisconsin–Madison

Carbon dioxide baited mosquito traps

These traps provided no protection from mosquito bites.

Many types of carbon dioxide baited mosquito traps have appeared on the market in the last ten years.  These traps attract mosquitoes through one or more of the following methods: the release of CO2,  light (UV or visible), heat, release of octenol.  Studies confirm that these traps do catch mosquitoes.  However, the key question is whether this results in a measurable reduction in the number of mosquitoes that land and bite humans in the area that is supposed to be protected by the trap.  For the average homeowner, answering this question is difficult because the number of mosquitoes in an area can change dramatically over the course of a few days regardless of trap use.  This happens because of natural cycling of mosquito populations or changes in weather conditions (windy, wet, cold conditions all reduce mosquito activity).  A good experiment would compare yards or areas with and without traps.  The study sites would be similar in mosquito activity and the key outcome (reduction in mosquito bites) would be measured.  Results of studies that are designed in this way indicate that traps purchased by individual homeowners usually do not work to reduce human biting (see references below).  For example, Mosquito Magnets do catch 1000’s of mosquitoes, but this does not change the biting rates in yards containing these devices.  

Although individual traps may not provide relief, the jury is still out as to whether an array of many traps in a neighborhood might be able to reduce biting.  Kline (2006) reported that an isolated Florida island with one dominant mosquito species was dramatically protected when Mosquito Magnets were deployed at a rate of 1/acre.  Studies using multiple traps in more typical neighborhood areas are underway in Florida but preliminary results did not indicate whether biting rates were affected (Kline 2006). 

Finally, some words of caution.  First, our research team’s experience with some of these traps (Mosquito Magnet) suggests that they break down frequently.  Of 3 traps we purchased for investigations, all were nonfunctional by the end of the first year of use (the plug-in model was more reliable than the freestanding model).   It is worthwhile to look at the comments of others who have purchased the model of interest to judge reliability.  Second, some traps make claims that cannot be verified.  For example, the Dynatrap marketing materials state that a novel method of CO2 generation is used, based on a titanium dioxide insert that interacts with UV light.  However, when we attempted to measure the output of these traps, we detected no CO2 at all (unpublished results).  Buyer beware.

Mosquito Magnet 1 small

References

Kline D.L. 2006.  Traps and trapping techniques for adult mosquito control. Journal of the American Mosquito Control Association 22:490-496.

Collier B.W., Perick M.J., Boquin G.J., Harrington S.R. and Francis M.J. 2006.  Field evaluations of mosquito control devices in southern Louisiana.  Journal of the American Mosquito Control Association. 22:444-450.

Henderson, J. P., Westwood R., and Galloway T. 2006.  An assessment of the effectiveness of the Mosquito Magnet Pro model for suppression of nuisance mosquitoes. Journal of the American Mosquito Control Association. 22(3):401-407