What’s the buzz? More natural mosquito repellents hitting the market | KEYE Austin - Green Right Now
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Jul 102009

Photo: CDC Public Health Image Library

Female Aedes aegypti mosquito, which spreads dengue

By Melissa Segrest
Green Right Now

Ahh, the sounds of summer. Birds chirping, food sizzling on the grill, the buzzing and buzzing and buzzing, the slapping, the spraying and, of course, the slamming of the back door as everyone races back inside.

Summer’s biggest bummer is that swarm of mosquitoes heading your way. As if their irritating blood-sucking isn’t bad enough, they can carry serious diseases.

Of the roughly 200 species of mosquitoes in the U.S., according to the fact-filled American Mosquito Control Association website, there are varieties that can transmit West Nile virus, malaria, dengue and Eastern Equine encephalitis.

There are lots of products on the market that promise to repel mosquitoes. The ones considered most effective, since 1957, contain the chemical DEET. It’s been approved by the EPA, the American Academy of Pediatrics and Centers for Disease Control for use on anyone older than 2 months.

But there are alternatives, derived from natural ingredients, for those who worry about using DEET, which has been known to cause skin rashes and neurological health effects in rare cases.

Aside from DEET, two  more mosquito repellent ingredients top the CDC’s approval list: the synthetic chemical picaridin, and oil of lemon eucalyptus. The CDC considers both to be as effective as DEET.

Picaridin is the most popular repellent in the world outside the U.S. It’s odorless, feels pleasant and, although derived from a pepper, is synthetic. There are only low concentrations for sale in the U.S. Cutter Advanced Sport has 15 percent picaridin and can only be used once daily, or 7 percent Cutter Advanced which can be used three times daily.

Lemon eucalyptus is now the most recommended natural mosquito repellent for consumers. It is sold as Repel Lemon Eucalyptus ($7.50 for 4 oz.) and is a botanical that’s OK for kids at least 3 years old. Consumer Reports, in a 2006 study, said it was the best non-DEET repellent. It’s sold at many large retail stores.

Another CDC-recommended anti-bug ingredient considered a biopesticide is IR3535, a synthetic version of an amino acid. It’s in Bull Frog Mosquito Coast (20 percent IR3535) and Avon has it, along with sunscreen, in their Skin So Soft Bug-Guard Plus.

After these “officially approved” mosquito repellents, there are a cornucopia of “natural”  items  that claim to keep bugs at bay. Determining their efficacy is tricky, if not impossible.

The most familiar among them is citronella, derived from the lemon-scented citronella grass (not the same as lemongrass). We’ve been burning it in candles and coils, or applying citronella oil-infused bug deterrents for years (although it can irritate the skin).  Unfortunately, studies have shown that the lotion works for less than 20 minutes, and if you’re not standing in the candle’s smoke, you’re probably being bitten. It is also sold by major retailers and there are lots of options on Amazon.com.

More recently, other essential oils have been getting attention as natural insect repellents. Among the most popularly: neem, garlic, mint, pepper, thyme, cedar, geranium, peppermint, soybean, eucalyptus, rose, tea tree, castor, basil, cloves, onions, feverfew, cinnamon, lemongrass or rosemary.

There are also lists of natural mosquito control ingredients from the National Sustainable Agriculture Information Service, The Green Guide, Consumer Search and AltMedicine at About.com.

Photo: CDC Public Health Image Library

Mosquito Fish, which can eat their weight in mosquito larvae daily

By the way, just because a product is “botanical” doesn’t make it safe. Products with pyrethrum (extracted from a daisy) have a “caution” rating from the EPA and can be toxic to fish and possibly birds. Other “natural” ingredients that could be risky are nicotine sulfate and sabadilla. Consumer Search says Canada is phasing out the use of citronella and lavender oil because of potential health risks.

A few natural repellents pop up repeatedly in recommended products: Bite Blocker ($9 for a 4-oz. spray bottle), Buzz Away Extreme Natural Insect Repellent ($10 for a 4-oz bottle), Burt’s Bees Herbal Insect Repellent ($8 for 4-oz bottle) and EcoSmart Organic Insect Repellent ($7 for a 6-oz. bottle).

Searching the web will turn up hundreds of other options. There are home-made recipes online, using everything from vanilla extract to soybean oil to catnip oil – but don’t apply oils directly to the skin (dilute them with other ingredients), as they can irritate or cause an allergic reaction.

One approach that’s been around for a few years, but just last year hit the market in the form of a skin patch called Don’t Bite Me, is the use of Vitamin B1. Exuded through the skin, B1 is reportedly offensive to mosquitoes, but undetectable to barbecue companions. Don’t Bite Me patches, available at Rite Aid drugstores and Kroger groceries, claim to fend off mosquitoes for a full 36 hours and provide complete body coverage (because it’s systemic not a lotion or spray there are no missed spots). The scent “forms a protective barrier around the body” says the press release. The product has received some positive anecdotal reviews, but skeptics of this approach abound.

What doesn’t work? Bug-zappers kill mostly useful insects and very few mosquitoes, according to the American Mosquito Control Association. Ultrasonic devices have been proven ineffective in 10 studies. There are new sticky, specially scented mosquito “traps” that may catch some bugs, but the jury is still out on those. Fancy, expensive misting systems may work, and can use less toxic chemicals, but they still disperse a lot of insecticide in the air and on your patio or deck.

Photo: CDC Public Health Image Library

Fertile breeding grounds for mosquitoes — rainwater-filled bottles and cans

And bats? Sure, it could be fun to build a bat house, and the Bat Conservation Society has lots of varieties you can buy. While it’s true that bats mostly eat insects, they generally prefer beetles, wasps and moths. According to the American Mosquito Control group, mosquitoes make up less then 1 percent of the diet of wild bats. Oh, and remember bats can transmit diseases, too.

All of which leads us to common sense ways to avoid mosquitoes:

  • Look for standing water in cans, buckets, tires, old plastic swimming pools, rain gutters, puddles and in tarps. That’s where they breed. Keep birdbaths fresh and stock your ornamental pond with fish that like to eat larvae.
  • Some bugs like perfumes, lotions, scented deodorant, etc., so you might want to skip those
  • Make sure the screens on windows and doors are OK.
  • Wear long-sleeved shirts and pants if you’re going to be around the biters for a while. And you can put the repellent on your clothes, too.
  • Plant mosquito-unfriendly plants such as marigolds, citronella grass, catnip or horsemint.
  • Ready to give up? Just don’t go outside between dusk and dawn.

Hungering for answers to questions about mosquitoes? The Mosquito Control group has a frequently asked questions page. Find insect repellent facts from the CDC, as well as more information on the active ingredients in repellents. They also have a list of practical steps to take to minimize mosquitoes.

Having a plan is a good idea. Consider these facts about the diseases mosquitoes transmit:

  • Last year, there were 1,356 confirmed cases of West Nile virus in the U.S., with 44 deaths (California had the most cases), according to the CDC. Last month, the first human case was confirmed this year near Los Angeles. Less common in this country is dengue, which has cropped up in the U.S. 3,806 times from 1997 to 2004. Worldwide, though, more than 100 million people fall ill every year.
  • Malaria, also spread by mosquitoes, kills more than 1 million people around the world, most in Africa. About 1,300 cases are diagnosed in the U.S. every year, the CDC says, mostly in travelers and immigrants. More lethal is Eastern Equine encephalitis, which usually only impacts horses or birds. There are only about five human cases in the U.S. annually, but it is so lethal that one-third of those infected die.

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