All Pennsylvania Hikers and Trail Maintainers Should Know About Permethrin

by Jim Foster

​Who doesn’t love to get outside in Pennsylvania?  After all, the name of our Keystone State means “Penns Woods”. But, once we get outside, we must deal with an increasingly common problem:  ticks and the diseases they cause. The best-known problem is Lyme disease. It is transmitted by the black-legged tick, sometimes known as the deer tick. According to a recent report by Penn Medicine, PA is the number one state in reported cases of Lyme, more than the next four states combined. 

Assuming we’re not going to spend our lives inside, what can we do? One well-known solution is to use a good insect repellent. Many folks like repellents that contain DEET. Others prefer non-DEET repellents like essential oils. Either way, a repellent is a really good idea.

However, plenty of folks have gotten tick transmitted diseases despite using a good insect repellent. Is there anything else to try? An increasing number of outdoor lovers are using permethrin. Permethrin is a pesticide that is chemically similar to extracts of the flowering chrysanthemum plant. Permethrin is not new. According to a report on National Public Radio, permethrin has been registered with the Environmental Protection Agency since 1979, and the EPA periodically re-evaluates it for safety. The Centers for Disease Control have also studied permethrin and found it to be quite effective and safe.

Permethrin works differently than insect repellants like DEET. Permethrin is an insecticide, meaning that it kills the bugs rather than repelling them. It’s been used for years to treat head lice and scabies. According to the EPA website, "All exposure scenarios showed that permethrin factory-treated clothing is unlikely to pose any significant immediate or long-term hazard to people wearing the clothing."

You can buy hiking clothing already treated with permethrin from vendors like REI. You can also purchase permethrin in liquid form and spray it on your hiking clothes. The liquid form is available from REI, Bass Pro, Cabela’s and other outfitters, and online from Amazon and others. If you do spray it on your clothes, you must follow the instructions carefully. 

Most instructions tell you to spray it on your clothes in a well-ventilated area like a garage with the door open. Wait several hours until the clothing is completely dry before you bring it inside. Above all, do not spray permethrin on your skin. But, after it has dried, it is quite safe for permethrin-treated clothing to come in contact with your skin. You should generally retreat your clothing after six to eight washings.

​I thru-hiked the Appalachian Trail several years ago and have also backpacked several other trails. Since I started using permethrin twelve years ago, I’ve had no problem with ticks. I like to use a good insect repellent with DEET in addition to clothes treated with permethrin. I encourage everyone who spends time in the woods to try permethrin.

Jim Foster is a former officer and board member of KTA. Jim currently chairs KTA’s Appalachian Trail Section committee.