BUG BITES Experts say chemical repellent is best mosquito protection

A soggy winter and spring have created ideal conditions for breeding grounds.
By ELAINE GASTON
KNIGHT RIDDER NEWSPAPERS
MYRTLE BEACH, S.C. -- You can douse yourself, fog your yard, hang a zapper, fill the air with ultrasonic soundwaves and install a killing machine in the corner of your property, all in an effort to repel mosquitoes.
Store shelves are packed with mosquito-repellent devices, from low-tech sprays and citronella candles to high-tech killing machines. You can spend as little as $2.29 or as much as $495 for protection against the female mosquito, the one who does the biting as she seeks blood to help develop her eggs.
If you're unsure about what works or doesn't work, bug and health experts say the most effective repellent is DEET, a chemical that when applied to the skin makes it difficult for a mosquito to find its prey. And products containing DEET cost much less than others available.
"DEET is pretty much the standard that's recommended," said Sue Ferguson, environmental health manager at South Carolina Department of Health and Environmental Control. "After many years of study, it's the most effective product to use."
The Centers for Disease Control and Prevention in Atlanta recommend that people use repellent when outdoors to reduce the risk of contracting West Nile Virus from an infected mosquito.
The CDC also recommends long-sleeved shirts and pants, using netting over infant carriers if outside and staying indoors at dawn or dusk, when mosquitoes are more likely to feed on people.
DHEC's Ferguson said a soggy winter and spring have created ideal conditions for mosquito breeding grounds in roadside ditches and marshy wooded areas.
"Mosquitoes are going to be worse this year," she said.
Before heading off to the stores to stock up on your mosquito arsenal, Ferguson recommended homeowners begin their battle with mosquitoes this year by first ridding the breeding grounds around their property.
"If you're still having problems, then I would get in touch with your local mosquito control program and let them help you find the source of the problem," Ferguson said.
Products containing DEET
Here are some ideas for what to look for when fighting mosquitoes: Look for skin products that contain DEET. Some product labels list DEET by its scientific name, which is N, N-diethyl-m-toluamide. Other non-DEET repellents may provide some protection but won't last as long as DEET, according to the CDC's guide to insect repellent use.
A product containing 23.8 percent DEET will provide about five hours of protection; 20 percent, about four hours; and 6.65 percent, about two hours. A product with 4.75 percent DEET and 2 percent soybean oil will provide less than 1 1/2 hours of protection.
The American Academy of Pediatrics recommends using low concentrations of DEET, 10 percent or less, on children aged 2 to 12, and always following application directions on the label.
Robin Sturkie, garden department manager at The Home Depot in Myrtle Beach, S.C., said she places tiki torches that use citronella oil around her outdoor living space.
For more high-tech options, bug zappers lure insects with their ultraviolet light, but mosquitoes make up less than 1 percent of the insects killed in zappers, the experts say.
"They can work, but you're calling them in, and you'll eventually going to get bit," Koesterer said.
On the extreme side of high-tech are machines that use low-frequency sound waves to deter mosquitoes. They can cost up to $300. For example, Applica's SonicWeb retails for $249 to $299 and is available at Ace Hardware stores or at www.sonicweb.com.
Koesterer said he's leery of the machines that claim to repel mosquitoes by emitting certain sound waves.
"They sound gimmicky to me," he said.
Killing machines
Mosquito trappers, such as Coleman's "Mosquito Deleto" and the Mosquito Magnet's "Defender" are gaining favor among homeowners despite price tags that range from about $200 to $500.
The companies say the machines work by using an attractant to lure the host-seeking female mosquitoes into a killing device.
The traps convert propane to carbon dioxide, which mosquitoes use to navigate to people.
Roxanne Rutledge, an extension specialist and medical entomologist at the Florida Medical Entolomology Lab at the University of Florida, wrote in a report about mosquito trapping devices that "one impressive large collection, a bag full, is a minute percentage of all the host-seeking females and will not likely impact these very large populations." Researchers at the lab are studying the devices and will release their findings upon completion of the study.