Mosquito traps
vary in their effectiveness at dealing with this common pest
Advertisements for mosquito traps promise the reduction or even eradication of one of the most bothersome pests known to humans. But the measured effectiveness of many of these traps---especially given their high costs and need for continual maintenance---suggests that much more research, development and testing is required. Does this Spark an idea?
Many Traps Mimic Human Hosts
Many of the mosquito traps on the market use a similar approach: a propane-powered unit creates heat and carbon dioxide, mimicking the human body temperature and exhalations of breath. The traps also use moisture, light, and one or more chemicals as attractants for mosquitoes. Two of the more common chemicals used are Octenol and Lurex. The latter has been found to be effective with the Asian tiger mosquitoes in the southern United States, but appears to have little effect on other breeds of mosquitoes.
Function
Once the mosquitoes are attracted to the trap, they are suctioned in with an impeller fan, forced through an electrically charged screen, caught on sticky paper, or otherwise captured in a net or jar. Some of the larger propane-powered traps are said to remove mosquito populations over an area of up to an acre and a half; others are said to work in much smaller spaces around human activity.
Costs and Upkeep
A challenge for many homeowners is the cost of the larger mosquito traps, which can run between $500 and $750. These are not appliances that can be set up and then ignored. There are propane tanks to refill or replace, and if the nets, jars, sticky boards or other capture devices are not emptied or cleaned on a regular basis their effectiveness will be diminished. Development of lower-cost mosquito traps continues. For example, one approach attaches a pyramid-shaped mesh net to a standard 20-inch electric fan that many homeowners may already have.
The Time Factor
Some advertisements for mosquito traps suggest that one can rid an area of mosquitoes in a week or less. According to the American Mosquito Control Association, these expectations are unrealistic. Mosquito traps must be given the time to capture the breeding females in the population. It will take 10 to 15 days to begin to see reductions in the number of active mosquitoes, and another two weeks to capture the mosquitoes that hatched from eggs laid during the first two weeks. After six to eight weeks, the breeding cycle will have been broken long enough to result in a reduction in the number of mosquitoes being trapped.
Effectiveness
While these traps can obviously capture mosquitoes with varying levels of effectiveness, their success depends on many factors, including the species of mosquito present; weather factors such as heat, humidity, and wind velocity and direction; and the proximity to marshy areas or other mosquito-breeding grounds. According to the AMCA, "the advertising claims for acre-wide control by these devices appear to be overstated. In most cases they are based upon the best-case extrapolations from captures of released mosquitoes made inside screened enclosures."
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