Researchers at New Mexico State University have been looking at the effectiveness of various mosquito repellents in keeping the summer scourges at bay. A study published last month built on the scientists’ previous work, and showed a wide range of potencies — and a few fragrant surprises.

DEET

Hands down — as opposed to them smacking your legs and neck — the most effective repellents the New Mexico researchers tested were DEET-bearing products, which turned mosquitoes away in droves. While health concerns have caused many consumers to search for alternatives, biologist Immo Hansen, senior author on two mosquito studies, says that research suggests DEET is safe for all but the smallest of children. And products with diluted concentrations can be used on them, he says. Some DEET products lowered mosquito attraction to human subjects from almost 90 per cent for those using no repellents to about 17 per cent for those slathered in them.

Oil of Lemon Eucalyptus

Another mosquito turnoff, products bearing this pungent substance rivalled those using DEET in their effectiveness, says biologist Stacy Rodriguez, lead author on the papers. Both substances work by interfering with the smell receptors on mosquito antennae, effectively masking the human odours the insects are searching out. “They can’t find us anymore,” Hansen says. He says smell is the primary search engine mosquitoes use to find their blood sources. Though the New Mexico team used the Yellow Fever Mosquito — Aedes aegypti. L. — and other southern counterparts in their research, Hansen says he’d expect to see similar results with the pests that swarm around Ontario campgrounds and cottages.

Citronella Candles

Hope you like the smell of that candle burning on your back porch —because mosquitoes certainly don’t mind it. Indeed, Hansen says they may even have a slight attractive element for the insects, with the carbon dioxide they emit being something the bugs seek out. “Citronella smells nice, so people like it,” he says. “It also gives you a nice ambience, but it doesn’t repel mosquitoes.”

Hansen says that many products make “ridiculous” claims to repellent potency, but that in times when mosquito-born ailments like Zika virus are growing concerns, studied were needed to test true effectiveness.

Perfumes

The old saw says that you should not wear flowery perfumes during mosquito season, because the fragrances attract the bugs. So the New Mexico team tried out Victoria’s Secret Bombshell on some subjects, who placed their perfumed hand in a tube that measured the insects’ olfactory responses. Surprisingly, the perfume — which one team member happened to have in her purse — produced a slight repellent response, says Hansen, whose studies were published in the Journal of Insect Science. He says the perfume has some two dozen ingredients and that the New Mexico team will be looking this summer at which of these might be driving mosquitoes away.

Sonic Devices

These are supposed to work by emitting sounds that mimic those made by mosquitoes that have already eaten blood, Hansen says. “The idea behind this is that these sonic devices produce a humming that is like a mosquito that has already taken a blood meal — a female mosquito,” he says. “This would, for some reason, repel male mosquitoes.” The problem with this, Hansen says, is that male mosquitoes — exclusively nectar feeders — don’t eat blood. “Its always the females and females are not going to be repelled by this.” One study, he says, suggested that people wearing these devices get bitten a little more. Some products claim to imitate the sound of insects that prey on mosquitoes.

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Bath Products

Some people swear that some personal hygiene products such as Avon’s Skin So Soft keep mosquitoes away. And while the team found a slight repellent action in the bath oil, it was almost insignificant, Rodriguez says. “There are a lot of products out there that don’t work,” she says. “And I guess part of the problem is that you go on Amazon and you type in ‘mosquito repellent’ (and) you get 25,000 hits.” Rodriguez says she’s seen mosquitoes land on some of the bracelet products sold as repellent devices.