Black flies are prevalent on the Long Trail in Vermont from spring through mid-summer. I’m going to be backpacking then and I’ve been devising some strategies to reduce the annoyance and health risk they pose.
My first line of defense is gong to be clothing. Although I hate hiking in long pants, I’m going to wear the bottom halves of my convertible pants as well as gaiters to keep the bugs from flying up my legs. I’m also going to find a highly breathable, lightweight long sleeve shirt. Average summer time temps on the Long Trail are in the low 70’s, so hopefully this will be tolerable except under periods of high exertion.
Next comes the hat system. Unfortunately, I can’t wear a head/bug net. Whenever I put a fine mesh net over my head, I get incredibly noxious and want to puke. I think it has something to do with being near-sighted. So, plan B is to wear a lightweight nylon billed hat with an optional skirt add-on to protect the back of my neck. I’m also going to try wearing a very lightweight balaclava for maximum coverage around the sides of the face and front of the neck.
My second line of defense is Permethrin. This is active ingredient on Buzz Off Clothing from Ex Officio. Ex Officio has recently replaced the Buzz Off brand name with the Insect Shield line of outdoor clothing.
Permethrin is a synthetic analog of a naturally occurring insecticide derived from chrysanthemum flowers. When applied to clothing it chemically bonds to clothing fibers as it dries remaining effective through multiple washings. It is not effective or toxic when applied to your skin, but kills black flies, mosquitos and ticks on contact when they land on treated clothing. It kills bugs by overstimulating their nervous systems. I guess they just freak out and die.
I’ve soaked clothing clothing in Permethrin, in the past, before going a safari trip to Tanzania, where the black flies are the size of bumble bees and make a chitenous crunch when you smash them against a Land Rover window. It worked really well then. I already have a Buzz Off hat and convertible hiking pants, so I will be soaking my shirt, balaclava, socks, and lightweight gloves in Permethrin.
My third line of defense is my Ben’s DEET. I love this stuff because it comes in a tiny 1.25 oz pump bottle that is lightweight and helps you accurately target the spray where it is needed without waste. I use the 100% strength as well as the 30% strength. The 30% strength will retain its efficacy for about 5 hours on your skin, according to the FDA. The 100% strength retains it’s efficacy for 10-13 hours depending on insect type.