Insects & Bugs

Good news, everyone! Compared to the Appalachian and Florida Trails, insects and other bugs aren't much of a problem on the PCT. Hikers rarely get bitten by ticks, mosquitoes are only a nuisance in a few places, and generally it's very pleasant.


On other trails there are specific locations where mosquitoes are a persistent nuisance: the Everglades canals on the Florida Trail, or a notorious two-mile stretch in Massachusetts on the Appalachian Trail. We can't provide such specificity for the PCT, however. Obviously with such little water in the desert there are no mosquitoes for the first 700 miles. But while mosquitoes are found in the Sierras, Oregon, and Washington their numbers, hatching times, and locations vary widely from year to year.

The Mosquito Hatch Cycle

Temperature determines when mosquitoes hatch and the amount of water determines how many there will be. Generally, mosquitoes won't hatch until temperatures are above 50 degrees, and the map to the right illustrates when that happens across the country, however the Sierra Nevada mountains are much higher than the surrounding landscape so warmer temperatures don't arrive until a few weeks later.


The amount of snowfall the previous winter determines the amount of meltwater flowing into meadows (Sierra meadows are seasonal wetlands), which determines the number of mosquitoes. The notoriously wet year of 2011 saw lots of mosquitoes on the PCT while subsequent years of intense drought have seen few mosquitoes.



When you enter the Sierras and how much snow fell that winter will determine mosquito conditions during your hike. You might face huge swarms while hikers who arrive three weeks after you encounter none at all, or vice versa. Conventional wisdom is that in a normal snow year, High Sierra bug season ends the second week of August, however thru-hikers should be well past the Sierras by then in order to reach Washington before snow starts falling. In other words, thru-hikers entering the Sierras in June and July should plan for the worst and carry both bug repellent and a head net.


Northern California

Most thru-hikers reach this section in early July. The mountains are lower so there is less snow and corresponding meltwater, hence fewer mosquito breeding places. This section still has a Mediterranean climate with wet winters and dry summers, so in July the landscape is drying out and mosquitoes are far less of an issue than in the High Sierras.



Most thru-hikers enter Oregon in early August, and mosquitoes can persist until September.



Cool autumn temperatures have arrived by the time thru-hikers reach Washington and mosquitoes stop being a concern.

Ditch the DEET

We are strong advocates for using non-toxic, non-polluting products in the backcountry. You would never leave food wrappers or other trash on the trail, so you should not leave toxic chemicals behind either. We strongly discourage you from using products that contain DEET, which is toxic to both humans and the environment. It also stains nylon and polyester clothes and leaves an oily residue on skin and gear that is impossible to clean in the backcountry. Once on your hands, this residue ends up on your guidebook, maps, journal, toothbrush, water bottle, water filter, pots, utensils, et cetera, and we don’t want to eat DEET, right?  Besides, there are alternatives that work just as good.

Mosquito & Tick Repellents

There are many natural bug repellents on store shelves and lots of home recipes online, but after a long (and still ongoing) search, we have found only two non-toxic, non-DEET alternatives that work to our satisfaction: EcoSmart Insect Repellent and All Terrain Herbal Armor. 


Products that fail to deliver are often made from combinations of lemon and eucalyptus oils. While these smell nice, the mosquitoes keep coming so avoid the following:  Natrapel, Cutter Lemon Eucalyptus, Repel Natural, and OFF! Botanicals.

Expert Tip: Carry a Pee Bottle

In parts of the Sierras, the potential presence of mosquitoes hordes makes it a good idea to carry an empty 32oz Gatorade bottle. If you need to pee at night, just pee in the bottle instead of unzipping the tent to face hordes of mosquitoes (and inevitably letting a few inside). Gatorade bottles have wide mouths that make it easy and 32oz is a good size in case you need to go again later. Women can even do this if they use the pStyle.


Arizona bark scorpion, photo by Mudsides via Wikipedia
Arizona bark scorpion, photo by Mudsides via Wikipedia

These desert-loving arthropods are nocturnal, so when intense daytime temperatures inspire you to night hike, don't be surprised to see scorpions crossing the Trail. If you want to see something super cool, take a blacklight LED flashlight with you on night hikes. All scorpions glow under blacklight.


About half of North America's scorpion species live in Southern California; only Arizona has more. There is just one species that is dangerous to human beings, the Arizona bark scorpion, which is found in both Arizona and California and should not be confused with the Baja California bark scorpion which is not dangerous. Although thousands of people are stung every year by bark scorpions in Arizona, only two deaths have been recorded since 1968.


How You'll Get Stung

You'll step on one while wearing flip flops during a midnight pee. After reading through accounts of Arizona residents who've been stung, we found flip flops was the most common element linking their stings. The bark scorpion isn't very big, so if you were to step on or near one while wearing shoes/boots its stinger couldn't reach over your shoe. If your bare feet are in flip flops, however, they'll get you. Also be sure to shake out your shoes each morning in case one crawled in there overnight.


What To Do If Stung

While it likely won't kill you, a bark scorpion sting is very painful. Symptoms persist for 24-72 hours, which may include numbness, tingling, burning, vomiting, shortness of breath, blurred vision, electric-like jolts of pain, paralysis around the sting location, and even seizures. Anti-venom is available, though you have to get to a hospital. Out on the Trail your first aid options are limited:


  • stay calm and if possible, kill and save the scorpion to show doctors
  • remove any rings, bracelets, boots and tight clothes before swelling begins
  • disinfect the sting with alcohol or wash with soap & water
  • take acetaminophen (Tylenol) every 4 hours to relieve the pain
  • if you have to walk out to reach the nearest source of help (which is likely) sit calmly for a few minutes, then walk calmly and avoid unnecessary exertion
  • have someone else carry your pack if possible — if you are alone, do not leave your pack behind, since it contains everything that will keep you alive
  • get to a medical facility


  • don't cut the wound or try to suck out the venom
  • don't use a snake bite kit on the sting
  • don't take ibuprofen (Advil, Motrin) or aspirin, because they can create complications

Cowboy Camping?

The question of scorpions on the PCT comes up most often in questions and conversations about cowboy camping. Mild temperatures, little precipitation, and an absence of mosquitoes make hikers want to sleep on the ground, under the stars, like the cowboys did. It is a beautiful experience, but one that is attached to anxiety about critters in the dark.


Frankly, you do run the risk of waking up to the sight of a scorpion or even a rattlesnake when cowboy camping. Accepting that fact will keep you calm if it happens. However the odds of any harm coming to you seem low. We have not been able to track down confirmed instances of Arizona bark scorpions stinging someone while cowboying.


Good news! Compared to the Appalachian Trail or Florida Trail, your chances of getting bit by a tick on the PCT are almost zero. Even the PCTA is confident enough about this to state, "Most people travel the entire trail without getting a tick."


That means you don't need to go to extreme measures to prevent bites — wear all the shorts you want! But you should still perform tick checks. They typically crawl up your legs and head for your groin, so take a peek at night before bed. There are three species of tick living along the PCT, all of which transmit pathogens to humans:

Rocky Mountain Wood Tick
Rocky Mountain Wood Tick
Western Blacklegged Tick
Western Blacklegged Tick

Bite Prevention

Usually, ticks are ambush hunters who climb vegetation and wait for an animal to walk by then leap on. When the Trail is overgrown or surrounded by tall grass, you are most susceptible to ticks. Prevent bites by wearing long pants with your pant legs tucked into gaiters so that ticks cannot crawl up your leg inside your pants. They like to go for the groin. The extra step of spraying your pants with insect repellent at the ankles and waistband is often essential on the Appalachian and Florida Trails, but seems overly cautious on the PCT



Remove attached ticks with fine-tipped tweezers. Grasp the tick as close to the skin's surface as possible and pull straight back. Do not twist the tick, because its mouthparts may break off in your skin and can become infected. Be careful not to squeeze or crush the tick since the tick's bodily fluids may contain pathogens. No folk remedy actually works: suffocating the tick with Vaseline or nail polish, touching a hot knife to the tick, et cetera.

Reported Cases of Lyme Disease, 2014 via the CDC
Reported Cases of Lyme Disease, 2014 via the CDC

Lyme Disease

The most common tick-borne disease in the US is Lyme disease, which most hikers are already familiar with. Fortunately for PCT hikers, the odds of contracting Lyme are far lower than on the AT. According to the CDC, in 2014 there were just 65 confirmed cases of Lyme disease in California, Oregon, and Washington combined. By comparison, Pennsylvania alone had 6470 confirmed cases, Massachusetts 3646, and tiny Connecticut 1719. Consider those figures in light of the fact that California is the most populous state in the country and that outdoor recreation is incredibly popular out west.

Reported Cases of Rocky Mountain Spotted Fever, 2014 via the CDC
Reported Cases of Rocky Mountain Spotted Fever, 2014 via the CDC

Rocky Mountain Spotted Fever

Both the brown dog tick and Rocky Mountain wood tick carry RMSF, which can be fatal if not treated with antibiotics within five days of symptoms. After an incubation period of 2-14 days, people experience headache, fever, chills, nausea, vomited, diarrhea, and other symptoms before small pink spots appear at the wrists and ankles. The spots then spread across the body and darken. Surprisingly this disease is most prevalent in North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri, not the Rocky Mountain states. In 2014 there were just 18 cases in California, Oregon, and Washington combined.

Reported Cases of Tularemia, 2014 via the CDC
Reported Cases of Tularemia, 2014 via the CDC


The Rocky Mountain wood tick carries tularemia, which is a bacterial infection affecting humans and animals. House cats are particularly susceptible to the disease, as are rabbits and other rodents, which die in large numbers during outbreaks. People catch the disease not only from tick bites but from handling infected animals and carcasses or eating undercooked meat. A water source contaminated by an infected animal can transmit the bacteria, though the CDC says this is more common in Europe than America. In 2014 there were 7 cases of tularemia in Oregon and Washington and none in California.

Reported Cases of Anaplasmosis, 2014 via the CDC
Reported Cases of Anaplasmosis, 2014 via the CDC


In addition to Lyme, the western blacklegged tick carries anaplasmosis, which is a more mild disease than Lyme or RMSF and rarely fatal. After 1-2 weeks of incubation, common symptoms like fever, chills, headache, muscle pain, and nausea appear. It is treated with antibiotics. In 2014 there were five cases reported in California and none in Oregon and Washington.


bees lick moisture from moss at this reliable spring on the PCT
bees lick moisture from moss at this reliable spring on the PCT

A surprising number of bees live around the PCT in the desert section, although you'll only see them at springs. With few sources of water in the desert, bees rely on the same springs as hikers, so you may find them swarming when you stop to refill.


You and the bees can share the water because you are not threatening their hive. Bees only attack when defending their hive.


Killer Bees? No.

So-called "Africanized" or "killer" bees are now found throughout the southern United States and yet, somehow, our nation is still standing. Before the hybridized bees entered the US in the 1990s, we had to endure hysterical news reports and movies like 1978's notorious The Swarm, starring Michael Caine and Henry Fonda, and 1974's Killer Bees  starring Gloria Swanson. The only voice of reason back then was Saturday Night Live, whose very first reoccurring sketch was "The Killer Bees."


There is no way to tell whether a bee is hybridized or not except test its DNA and since 75% of the wild bees in Southern California are hybridized, odds are the bees we photographed above were "killer" bees. The truth is, their danger has been wildly exaggerated. European honey bees are the only domesticated insects in the world and we humans have bred docility into them. So-called killer bees aren't extra aggressive — they're perfectly normal wild bees.


We bring this up because occasionally you might hear rumors of hikers being chased by killer bees, like this blog that repeats a second-hand story without any details. We've found no evidence a PCT hiker has ever been attacked by a swarm of bees, and the PCTA makes no mention of bees, killer or otherwise, anywhere on its website.