Permethrin is a man-made version of an insect repellent found in chrysanthemum plants. The molecule repels a variety of biting insects including flies, ants, chiggers, mosquitoes, ticks, etc. The company Insect Shield partners with manufacturers of work and recreational outdoor clothing to produce bug repellant gear: LL Bean, Buff, Carolina Manufacturing (bandanas), Eagle’s Nest Outfitters, ExOfficio, Outdoor Research, and REI.
Since deer populations have been exploding in many parts of the country, we have seen a corresponding explosion in the tick population. Some diseases carried by ticks can send you to bed for at least a week and may even have permanent effects (Lyme disease for example). Permethrin seems to be the best alternative for dealing with these pests and is a vastly superior alternative to DEET.
We were clued into this permethrin clothing treatment last year by Rob, a local farmer. He was finding about a dozen ticks a day after working in the fields. Rob started wearing permethrin treated socks, long pants secured at the ankle, long-sleeved shirts and a bandana; he stopped picking up ticks. I have shorts, an ExOfficio Bugsaway t-shirt, and several pairs of treated socks, and that seems to do the trick for me. There are also sprays for applying permethrin to your own clothing and camping gear (please read the warning labels carefully before using them) though I personally prefer pretreated clothing.
My favorite non-clothing use of permethrin is the Perky-Pet Ant Guard. It’s a small canister with hooks at both ends for hanging a hummingbird feeder. The canister separates into two parts held together with a central line; that central line is the only thing that’s treated with permethrin. Ants must crawl on the line to get to the feeder, thus minimizing any bird feeders over run by insects. Besides minimizing exposure to the environment, the treatment is protected from both sun and rain by the canister.
One thing to consider before using permethrin is that, as the Wikipedia article notes, permethrin is toxic to fish and aquatic life in general. This is why I dislike the use of permethrin backyard sprays as they seem like overkill, while any runoff can inadvertently damage local water life.