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What's the best way to take the sting out of mosquitoes?

Photo

James Gathany/CDC

A female mosquito takes a meal from a human host by sucking the blood through her labrum, visible here as a thin, red line between her head and the skin. Residents can expect to be fending off mosquitoes any day now.

They're coming.

Right now, microscopic eggs are sitting in pools of standing water. But soon, misery-making mosquitoes will be buzzing about backyard barbecues, pool parties and baseball games.

"Things are just starting," said UW-Madison entomologist Phil Pellitteri. "Almost every year, the first big emergence (of mosquitoes) is around the end of May. In a real warm year, it happens early. In a real cool year, it happens later.

"Let's just say there aren't tears in my eyes yet."

Rain has fallen but soaked into the dry earth. Temperatures have climbed into the upper 70s but dipped into the lower 40s. Neither is a good sign for mosquitoes, which require standing water and hot, humid weather for breeding.

"We're going to get ‘em soon," Pellitteri said.

All right, so we can't avoid them. But we can fend them off, right?

The Gazette took a look at some of the most common repellents and the lesser known remedies in anticipation of mosquito season. Which ones really work? We relied on research compiled by UW-Madison entomologist Susan Paskewitz and her students.

Here's what we found:

Yard protection

-- Baited traps

Examples: Traps such as the Mosquito Magnet or the DynaTrap insect eliminator, which attract mosquitoes by emitting carbon dioxide, light or heat.

Do they work? Yes and no. Studies show these traps catch thousands of mosquitoes but do not change the rate of mosquito bites in the area that is supposed to be protected by the traps.

-- Foggers, yard sprays and home misting systems

Do they work? Yes and no. Studies show these sprays keep mosquitoes away for a couple hours—long enough for a barbecue or party—but not much longer. But people often overuse these sprays, misting their yards several times a week, and put plants, animals and valuable insects at risk.

-- Lanterns, coils and candles

Examples: Off! Mosquito Lantern, Off! Mosquito Coil or citronella or geraniol candles

Do they work? Studies show that devices that emit allethrin or other pyrethroids can reduce the number of biting mosquitoes. Other studies show that citronella candles offer relatively small reductions in the number of biting mosquitoes, while other plant oil candles (geraniol) offer better protection.

-- Bats

Do they work? Not really. Research has shown that bats released in a room filled with mosquitoes could catch up to 10 mosquitoes per minute, or 600 mosquitoes per hour. But that research says nothing about bats out in the wild, where the community of insects that can serve as food is much more varied. Studies of bat feces have shown that mosquitoes usually make up only a very small percentage of their natural diet.

Personal protection

- DEET

Examples: Lotions and sprays applied to the skin, such as many Off!, Cutter or Repel brand repellents.

Does it work? Studies show that repellents with DEET concentrations of 20 percent or higher provide about six to eight hours of protection against mosquitoes but that repellents with concentrations of 5 to 10 percent provide at least a couple hours of protection.

-- Picaridin

Examples: Sprays applied to the skin, such as Off! Family Care Clean Feel repellent.

Does it work? Picaridin is a colorless, odorless liquid active ingredient that is an alternative to DEET. Studies show that repellents with picaridin concentrations of 10 to 20 percent provide good protection against mosquitoes.

-- Metofluthrin

Example: Off! Clip-On mosquito repellent, a small fan-powered device that clips onto clothing and circulates repellent.

Does it work? The product is relatively new, but the chemical is not. Metofluthrin is a vapor-active pyrethroid, and studies show that devices that emit such chemicals can reduce the number of biting mosquitoes. Off! claims the device provides protection for up to 12 hours.

-- Avon Skin-So-Soft

Does it work? Avon produces a line of Skin-So-Soft products designed to repel mosquitoes. The sprays and lotions contain picaridin or IR3535, both of which provide good protection against mosquitoes.

-- Lemon eucalyptus

Example: Repel Lemon Eucalyptus repellent

Does it work? Studies show that repellents with PMD (the active ingredient in the plant) concentrations of 20 percent provide about the same protection against mosquitoes as repellents with DEET concentrations of 20 percent.

-- Garlic or vitamin B

Do they work? No. Studies have not found evidence that eating garlic or taking a vitamin B tablet reduces mosquito attraction.

-- Vanilla extract

Does it work? No. Studies show that vanillan (the primary component in vanilla extract) provides little to no protection against mosquitoes.

-- Listerine

Does it work? The jury still is out on this one. No studies have confirmed or denied the claim that Listerine or other antiseptic mouthwashes kill or repel mosquitoes. The primary active ingredient in Listerine is eucalyptol, a derivative of eucalyptus oil, which commonly is used in insect repellents and has repelled mosquitoes in studies. But Listerine has a significantly lower concentration (less than 1 percent) of the oil than most repellents (at least 20 percent).