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Everyone has a tried and tested technique that they swear repels mosquitoes. From citronella candles to the curve ball, Avon Skin-So-Soft, we are each convinced that they are doing their job and keeping us safe from the sneaky little blood suckers. But how do we know they are actually doing their job and keeping the pesky insects at bay?
In light of the recent Zika epidemic, which is still bubbling away in the Americas, there has been renewed interest in mosquito repellents. So a new paper published in the Journal of Insect Science has decided to look into the efficacy of a range of mosquito repelling products, and we think it’s fair to say that for many of them, it’s not looking great. None of the 11 products that all claimed to work were 100 percent effective, and some were no better than no protection at all.
The researchers decided to test the repellents by placing a human “bait” in a wind tunnel alongside a mesh cage containing Aedes aegypti mosquitoes downwind, and recording whether or not the insects were attracted to, or repelled from the bait dowsed with the range of products.
They found that citronella candles have zero effect on repelling mosquitos, and in actual fact “attracted slightly more mosquitoes [than] the human bait person alone,” although they do note the difference was not statistically significant. All the spray-on products did repel mosquitos to a degree, but they still offer the high probability that you will get bitten, particularly if there are high numbers of the blood suckers around.
By far the most effective repellents were oil of lemon eucalyptus spray and DEET, which reduced mosquito attraction by 60 percent. And when it came to the plethora of wearable repellents, well, they were pretty useless too. Bracelets containing herbal repellents and sonic mosquito repellers, which apparently use high-frequency noises to banish the insects, were particularly terrible.
“We are not aware of any scientific study showing that mosquitoes can be repelled by sound waves and therefore we consider these devices as the modern equivalent of snake oil,” wrote the authors in a particularly scathing attack on the sonic devices.
There was, however, one piece of wearable tech that did have a positive result. The OFF! Clip-on Metofluthrin nebulizer that uses a fan to distribute the insecticide metofluthrin around the wearer was found to be pretty good at its job, and the only wearable repellent to actually repel the mosquitoes.
So there we have it. It seems the safest bet is to stick to spray-on repellents, but even this comes with a warning that they are not anywhere near as effective as they claim, and caution should definitely be taken if you are going to be exposed to large numbers of mosquitoes.
