Article by Rob Worthing, MD FAWM
I’ve always wanted to write something about biting insects for anglers. But, the inevitable distractions – like actually fishing – always got in the way. Today, I find myself in a position where I have no excuse. Instead, I appear to have a tick-borne illness. I got lazy, didn’t protect myself, and I got bit. As I sit at home, using up my sick days from work, enjoying a screaming fever, fatigue, malaise, headache, and one crazy bull’s eye rash, it only seems fitting that I write this article. So read up and arm yourself with some knowledge, because you don’t want what I got!
Each summer across fly fishing rags, forums, blogs, and social media outlets the debate over the best line of defense from mosquitoes, ticks, and other biting insects erupts. Why? Two reasons. First, these little bloodsuckers are annoying. Second, they carry diseases that we really don’t want. Diseases like Lyme, West Nile, Rocky Mountain Spotted Fever, and Tick-Borne Paralysis to name a few. Throw in Zika and a few news reports on Powassan virus this summer, and things get bonkers.
The difficult part for most of us fisherpersons is trying to figure out the good information from the bad. What really works, and what doesn’t work so well? What’s safe, and what’s not so safe to use? Many of us have a particular product that works well for us around our home waters. Such experience can be very helpful. To further help us make an educated choice, this article will summarize the best evidence on the subject of insect bite prevention that science has provided us to date. Only here the info is geared for real-world use by anglers, not so much the scientists.
A fly fisherperson can control biting insects in two ways. First, using physical barriers. Second, using chemical barriers like insect repellants. There’s also the not-so-effective, sometimes dangerous stuff out there that we ought to address. That gives this article a total of three parts – physical barriers, chemical barriers, and not-so-effective/dangerous stuff. And since the chemicals are what seem to be debated the most, we’ll subdivide a few to try and provide everyone with an evidence-based plan to prevent bites they can feel good about.
Physical Barriers
Physical barriers are your primary protection from biting insects. A physical barrier is anything that minimizes access of biting insects to your body, whether limiting exposed skin to flying insects, or entry points for crawling insects.
- Light colors. Light colors are less attractive to mosquitoes and certain biting flies and make it easy to spot crawling insects for removal.
- Layers. Tuck in your shirt and pants. Button sleeves and collars. Overlap base layers, socks, outer garments, and accessories like gloves. This eliminates entry points for crawling insects like ticks.
- Loose fit. This deters thru-bites from mosquitoes and certain biting flies.
- Long sleeves and pants. Limiting skin exposure minimizes access for biting insects. Popular sun protection items like fishing gloves, glasses, and neck gaiters help, too.
- A wide-brimmed hat. Black flies and midges avoid the area under the brim. That’s right, somebody actually published a study on wide-brimmed hats.
- Mesh. If you want to use a mesh head net, or looking at a mesh tent/bivy, get one that is 27 mesh/inch or finer to keep the smallest biting flies away.
Chemical Barriers
Choosing and using chemical insecticides and repellants can be intimidating, even scary. But if you want the most effective prevention strategies, you need chemical barriers. Here are the important facts about three different effective chemical strategies.
1. Permethrin + DEET
This is the most effective combo known, and it has the longest track record of safe use. Permethrin is a clothing treatment. DEET goes on the exposed skin. These products should be used in combination. Together, they can prevent 99.9% of mosquito bites (1 vs. 1888 bites/hour in one Alaskan study).
Permethrin:
- A synthetic version of a natural chemical found in chrysanthemums.
- It works by repelling insects and killing some on contact.
- Resulted in 100% tick death after contact with a treated cloth.
- Also effective against chiggers, fleas, lice, mosquitoes, and biting flies.
- Poor absorption and rapid inactivation in mammals, but you can still make yourself sick if you don’t use it right
- Meant for treating clothing only, NOT SKIN!
- Be sure the clothing is completely DRY before using
- Don’t treat underwear, base layers or the inside of hats. Socks are okay, though.
- It is also really toxic to aquatic life. Luckily, once dry it is water-insoluble, which means you can wear them fishing without any worry. Just don’t treat your clothes around any water sources, and (repeat) make sure clothing is completely DRY before using.
- Not only is it water-insoluble once dry, but resistant to UV degradation, too. It will still repel insects after as many as 50 washes, but its ability to kill flies on contact wears out faster.
- It binds to cotton and nylon really well.
- It does not bind to DWR treated fabric like your rain jacket and tent fly. A lot of outdoor shirts and pants have a DWR coating, too. So check before treating.
- It is flammable in liquid form, but dry clothes are fine. So treat your clothes before you travel – don’t try to bring a bottle on the plane.
DEET:
- Works by vaporizing, forming a barrier of vapor over your skin.
- Effective against mosquitos, biting flies, fleas, ticks, chiggers, and mites. But less effective against certain species of biting midges.
- 200 million users worldwide, less than 50 cases of significant toxicity in over 50 years of use. It has the longest track record of safety of any insect repellant, as long as you FOLLOW THE INSTRUCTIONS.
- Use on exposed skin only. No need to put it on under your clothes.
- Don’t put it around cuts and scrapes or mucous membranes like your eyes, nose, mouth, or genitals.
- Don’t rub it on your head. A little swipe on the back of the neck is fine.
- 100% DEET is BAD. It is less effective, and increase the risk of making yourself sick.
- Look for a 20-40% concentration of DEET. Less than 20%, and you loose duration of effect. There is zero added benefit to concentrations above 40%.
- Also look for a polymerized DEET. Polymerization slows the vaporization process. This stuff is controlled release, lasting 12 hours.
- It still repels if you sequentially apply it with sunscreen, only the SPF of the sunscreen might be reduced.
- DEET is a plasticizer. It melts plastic. Keep it away from your gear.
- For all of the above reasons, wash your hands really good right after putting it on, before you touch your gear or go fishing.
- 3M Ultrathon and Sawyer Controlled Release are good. These are around 33% DEET in a polymerized form.
2. Permethrin + Picaridin
A great alternative for anglers. We already covered Permethrin. Picaridin is a skin repellant like DEET, only with some bonus features.
Picaridin
- Used on the exposed skin similar to DEET.
- Effective against mosquitos, biting flies, and ticks.
- 20% concentration offers 8-hour protection.
- Not greasy like polymerized DEET.
- It won’t melt plastics, and won’t hurt your gear.
- It’s a newer product, so it doesn’t have the long track record like DEET does. But studies so far suggest it is as effective and safe.
- Natrapel makes a great 20% picaridin option.
3. Oil of Citronella
For those who want an effective all-natural option.
- The most effective botanical repellant.
- EPA registered in 1948, so it has a long track record of safe use, too.
- But you still have to FOLLOW DIRECTIONS to avoid getting sick.
- Used on exposed skin like DEET and Picaridin.
- The downside is a really short duration of effect. The recommendation is for reapplication every hour to maintain its efficacy.
Not So Effective/Dangerous Stuff
- Area Repellants. Candles, coils, butane burners, vermiculite, etc. Their efficacy under ideal conditions varies widely. Wind, humidity, and other environmental factors impact the effective area. In Japan, incense coils burn regularly around the dinner table after a long day of fishing. If you’re going to fork out the dough, just know that the evidence is kind of weak and that their ability to deter insects is dependent on a lot of other things.
- For Wear Devices. Bracelets, pins, and the like. Their efficacy is limited to the immediate vicinity around the device. In other words, the skin right around the bracelet on your wrist. Might be enough if you’re covered up, but there is likely a better option out there for you.
- Animal Products. Flea and tick collars, cattle tags, and the like. These contain a variety of pesticides not cleared for human use. Adverse local and systemic effects are associated with use in humans. For example, more than one Marine or Soldier has suffered chemical burns on their legs from using flea collars as anklets. Leave the animal products to the animals.
- Ingested Products. Garlic, vitamin B1, and more. There just isn’t any evidence to support their use. Some can be harmful. For example, eating match heads to prevent chigger bites. Sulfur products used on the skin are, in fact, effective against chiggers. But eating match heads doesn’t work. Neither does getting drunk. In fact, the metabolites that leak out of our skin after a heavy night of drinking might attract certain flying insects.
Rob Worthing has had a fishing rod in hand for over 20 years. An avid angler, world traveler, backpacker, and wilderness medical professional, he enjoys going off the beaten path to find the best fly fishing possible. He is passionate about fishing tenkara in remote mountain streams. In addition, Rob takes great pride in combining techniques learned while fishing six continents and four oceans to create hybrid fixed line fly fishing styles that simply catch fish. He is one of the founding partners of Tenkara Guides, LLC.
This article originally appeared in the Summer 2017 issue of Tenkara Angler magazine.
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