BITING BUGS -- In researching today's column on coping with biting insects, I noticed frequent references and praise to a relatively new and effective active ingredient for insect repellents that works on black flies as well as mosquitoes.

While DEET, developed by the U.S. Army in 1946, has become a household word for insect repellents that are effective especially for mosquitoes and ticks, picaridin has remained less-known.

Picaridin has been widely used as an insect repellent in Europe and Australia since it was developed in the 1980s, but has been available in the United States only since 2005. It's proved to be effective against mosquitoes as well as biting black flies and noseeums.

Repellents using picaridin got a publicity boost last year with an endorsement from Consumer Reports.

"The overwhelming majority of repellents are not effective against flies," Travis Avery, spokesman for Sawyer Products, said in an interview. "That's one of the reasons picaridin is so popular elsewhere around the world, and why it's becoming the new standard around the United States."

Sawyer makes repellents in spray and lotion with 20 percent picaridin.  "Lower concentrations aren't as effective as we'd like," he said.

For the best protection when biting bugs are winning the battle, he recommends -- as do I -- a combination of covering up with protective clothing, treating some clothing and then using small amounts of insect repellents.

Clothing treated with permethrin insecticide helps ward off mosquitoes and ticks. "The treatment with our product will last six weeks or six washings," Avery said.

Although permethrin is to be applied to clothing, not to human skin, the product is used on horses and Sawyer has web page information on using it to repel ticks from dogs for 35 days.

My system has been tested and proven in epic bug concentration areas such as the Arctic National Wildlife Refuge in Alaska and Boundary Waters Canoe Area in Minnesota.   I wear lightweight long pants, long-sleeve shirts with a collar and a cap with a sun flap that falls over my ears and neck. I treat my cap, shirt collar and pant legs and socks with permethrin before trips when bug conditions warrant the protection.

Modern sun-block shirts and fast-dry pants are cool and comfortable.  They're a pleasure to wear and they leave less bare skin available for a black fly feast.

When the bugs are really bad, cover up as much as possible and your need for repellents is minimal.