Efficacy of electronic mosquito repellers
Mosquito nuisance and their ability to transmit diseases are steadily stimulating the launching of new tools in the market to tackle these problems. Different electronic mosquito repellers, often called ultrasonic mosquito repellers are being produced for several decades already, but the funny thing is they don’t really do what are supposed to.
Several scientific experiments around the year 2000 were carried out to check whether electronic devices really repel mosquitoes and all of those experiments showed they don’t.
Yet one more laboratory study was performed by I. Cabrini and C. F. S. Andrade in Sao Paulo, Brazil in 2006. They checked the efficacy of 6 different electronic mosquito repellers that were offered by manufacturers from Brazil, USA, China and Thailand. One of the devices inspected did not produce a recordable fundamental frequency at all. Other evaluated repellers showed frequencies ranging from 7.2 to 22kHz, only the highest of which was ultrasound.
Test-chamber was used to check the efficacy of repellers on females of Aedes aegypti. The resulting repellency efficacies, or even some attraction, were always very low (with more than 90 percent of females reaching the should be “uncomfortable” section of test-chamber) and not significant.
Another hoax used in advertising of electronic mosquito repellers is saying that imitating the male wing beat sound would repel conspecifc females, while experiments showed opposite. Moreover, wing beat frequency for male mosquitoes has been recorded to range from 400 to 900 Hz, which is quite different from that presently found for most repellers.
Also, when back in 1993 Barrido with colleagues evaluated electronic repellers, four out of six devices showed a significantly higher attraction when turned on.
Some electronic repellers were banned at least in the USA. For example, the directors of Lentek International Inc. (the manufacturer of “Mosquito Control” system) were charged and prohibited in 2002 by the Federal Trade Commission (FTC) from commercializing their electronic repellers for a period of 5 years, due to false allegations and unsubstantiated claims in their advertisements for electronic mosquito and pest repellers.
So finalizing one could say that electronic mosquito repellers have been scientifically proven not to work again and again over a period of quite a few years, but people keep buying them, because the claim that they should work seems so plausible. And the commercialization of new electronic mosquito repellent devices is still ongoing in many countries.
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