Hidden Hazards in the Canopy – Part Two

Eight-Legged Threats

Unless you’ve been living under a rock, you’ve probably seen recent headlines warning the public about serious tickborne illnesses. Alpha-gal syndrome (AGS) and Lyme disease are affecting thousands across the country, and outdoor workers are at an especially elevated risk. With the complications of these diseases ranging from severe gastro-intestinal distress to anaphylaxis, the risk of tick bites cannot be understated.

To help mitigate such risks, Dawn Thierbach, ISA Certified Arborist and co-proprietor of Victorian Gardens, develops and conducts webinars in collaboration with Streamside Green to educate arborists about the hidden hazards crawling and buzzing about the canopy.

“We developed the webinars during COVID because CEUs weren’t available at the time,” she explained. “We wanted to provide arborists with safety information focused on common encounters with insects and animals.”

During the webinars, educators emphasize the importance of PPE, hazard assessments, and first aid for stings and bites. But above all, the webinars stress the need for arborists to research local wildlife, and to educate themselves on potential hazards to ensure safety in their work.

“Arborists aren’t without hazards,” Thierbach shared. “You need to know what you’re dealing with, and what you should be looking for. Keep your eyes peeled for things like squirrels, ticks, spiders, water moccasins, snakes, alligators, hornets…I could go on and on.”

Just as important is performing a job briefing before work begins. In doing so, you might spot a web, nest, hive, or eggs, indicating a wildlife hazard is present. Depending on the animal or insect, you may choose to delay work until the hazard has been properly removed by local wildlife professionals or an exterminator.

To continue our safety series on bites and stings, this article will take an in-depth look at ticks and spiders including where certain species live, common disease and bite symptoms to watch for, and helpful tools and equipment you can use to protect yourself from a bite.

Arachnid Bites: Ticks & Spiders

Tick Bites

In recent headlines, tickborne illnesses – such as Alpha-gal syndrome and Lyme disease – have been a hot and concerning topic. The CDC estimates that nearly 450,000 people in the United States may be affected by AGS, while over 89,000 cases of Lyme disease were reported by state health departments and the District of Columbia in 2023 alone.

These debilitating and potentially life-threatening conditions are increasing across the United States and are often the result of a tick bite.

An Inescapable Risk

While ticks are most active during warmer months — typically April through September — bites can be problematic year-round as long as outdoor temperatures stay above freezing. In fact, 2026 is slated to be one of the worst years of the decade in terms of tick bites, partly in thanks to the mild winter conditions that kept these pests active for a longer period of time.

Part of the arachnid family, ticks are very tiny and difficult to spot, let alone feel, when crawling on the body and clothing. Tick larvae, or “seed ticks,” are so small, they only measure about 0.5 to 1 mm in size and are among the most prone to bite.

According to the CDC, many tick species are found throughout the world, but only a few actually bite and transmit harmful pathogens, bacteria, and viruses. The challenge? Those few species are widespread across the United States with dense populations wherever they are found. As it stands, 19 states have been designated as very high-risk zones for Lyme’s disease, the most at-risk region being the Northeast.

Unfortunately, arborists work in the conditions where ticks thrive the best — moist, shaded environments like grassy fields, thick brush, and heavily wooded areas. Groundsmen are especially vulnerable while cleaning up leaf litter and log piles, while climbers may come into contact with ticks at height in dense canopies.

Thierbach encourages all tree care workers to educate themselves about the types of ticks and tickborne illnesses common to their region: “By doing so, you’ll better understand what threats you’re facing and how to avoid or prevent bites.”

Common Ticks and Where to Find Them

One of the most concerning — but thankfully, identifiable — subspecies of ticks is the Lone Star (Amblyomma americanum). This species is identified by its deep brown body and a light yellow-ish dot in the center of its back.

A bite from this insect can cause Alpha-gal syndrome, which can result in an allergy to red meat, and in severe cases, severe anaphylaxis. Along with AGS, these ticks can also transmit ehrlichiosis, tularemia, heartland virus, bourbon virus, and southern tick-associated rash illness (STARI).

The Lone Star tick can be found across the entire United States, but their populations are heavily concentrated in the Northeast, South, and Midwest regions of the U.S.

View the CDC’s Lone Star Tick Surveillance map here.

Another species to be aware of is the American dog tick (Dermacentor variabilis). It’s most commonly found east of the Rocky Mountains, though this subspecies can still make an appearance in western regions. These ticks are most active during the warmer spring and summer months, with adult females being the most likely to bite humans and warm-blooded animals.

They are known carriers of Rocky Mountain spotted fever (RMSF) and tularemia, two potentially serious and even life-threatening diseases if left untreated. Rocky Mountain spotted fever can produce symptoms such as fever, headache, muscle aches, nausea, and a characteristic rash. If diagnosis and treatment are delayed, the disease can lead to organ damage, neurological complications, and death. Tularemia, meanwhile, can infect the skin, lymph nodes, lungs, and other organs, often resulting in fever, fatigue, swollen lymph nodes, and skin ulcers at the site of the tick bite.

View the CDC’s American Dog Tick Surveillance map here.

For those working in the eastern part of the United States, the blacklegged tick (lxodes scapularis), or the deer tick, is a primary concern. This species is especially prevalent across the northeast, including Maine, Massachusetts, and New York. It can also be found in nearly every part of Florida and along the coast of North Carolina. These ticks are very active for most of the year, except during winter or below freezing temperatures. And, just like the American dog tick, adult females commonly bite humans.

These tiny pests can transmit several serious diseases that pose risks to tree care professionals, including Lyme disease, anaplasmosis, and Powassan virus — a rare but potentially severe infection that can cause inflammation of the brain (encephalitis) or the membranes surrounding the brain and spinal cord (meningitis).

View the CDC’s Blacklegged Tick Surveillance map here.

But that’s not all — other species of ticks crawl about “out there.” These include:

• The Asian longhorned tick (Haemaphysalis longicornis) – Native to East Asia, this invasive species is now commonly found in the Northeast, Southeast, and Midwest.
• Brown dog tick (Rhipicephalus sanguineus) – Found worldwide.
• Gulf Coast tick (Amblyomma maculatum) – Primarily found in the southeastern United States, but has been spotted in the Northeast, Midwest, and Southwest.
• Rocky Mountain wood tick (Dermacentor andersoni) – Found in — you guessed it — the Rocky Mountain states and southwestern Canada. It’s often found at elevations above 4,000 feet.

Symptoms of a Tick Bite

Because tick bites are known to transmit a wide variety of illnesses and conditions, symptoms will also vary.

At the bite site, localized symptoms may include:

• A small, itchy red bump – this may appear within an hour or two of the bite.
• A bull’s-eye rash known as erythema migrans. If this develops, it often signals Lyme disease; however, this isn’t a definite sign of the condition.
• Small, red, or purplish blood spot rash on the skin around the bite site. This type of rash can indicate Rocky Mountain spotted fever.

Systemic illness may also appear within one to four weeks of the initial bite. These symptoms may include:

• Fever and chills
• Headaches or migraines
• Muscle and joint pain
• Extreme fatigue
• Swollen lymph nodes

If any of the above symptoms occur, it’s best to consult a healthcare provider immediately. For more information on tickborne illnesses and their related symptoms, visit the CDC Tickborne Diseases Guide.

PPE Recommendations

While working in an area where ticks are prevalent, consider using the following PPE:

• Wear light-colored clothing, like a bright yellow or orange high-vis vest. This will help make ticks easier to spot.
• Tuck pants into thick socks or boots. Some arborists even swear by wrapping duct tape (sticky side out) around the ankles to trap ticks.
• Wear chemically treated (0.5% permethrin) clothing designed to ward off ticks and other pests.
• Wear thick gloves, especially when working with brush, leaves, or logs.
• Apply an Environmental Protection Agency (EPA)-registered insect repellent spray.* Look for products that contain DEET, Oil of Lemon,    Eucalyptus, para-menthane-diol, picaridin, IR3535, or 2-undecanone. Focus on spraying the ankles, waistline, wrists, and neck.

*Note: If you’re also planning to wear sunscreen, apply the sunscreen first then spray yourself with an insect repellent for best results.

Additional Tick Bite Prevention Tips

Thierbach knows all too well what it’s like to come home after a job covered in ticks.

“My husband and I were on a consulting job together. I had my hair up in a ponytail and a hat on. My husband also had a hat on, and he’s bald,” she recalled. “When we got in the car, I looked down and had ticks crawling on my shirt. When I took off my hat, there were ticks everywhere. They were in my pants and in the tiniest places. Oh, it gives me the heebie geebies just to think about it!”

To prevent ticks from latching, Thierbach encourages removing all work clothing, shaking them out, and performing a full-body tick check as soon as you arrive home. Also, carefully examine all gear for ticks. This includes helmets, backpacks, coats, boots, etc.

“Strip your clothes off outside,” she said. “You don’t want to bring ticks into your house where they can latch onto you later. Shake out your clothes, wash them, and do a full-body check.”

Ticks often hide and attach in the smallest, hard-to-see areas on the body. Be sure to check behind and inside the ears, in the hair and scalp, along the waistline, in the bellybutton, behind the knees, and even under fingernails and toenails.

After you’ve completed the full-body check, Thierbach said the next step is to “hop in the shower.”

According to the CDC, “showering within two hours of coming indoors has been shown to reduce your risk of getting Lyme disease and may be effective in reducing the risk of other tickborne diseases.” Additionally, showering could be effective at washing away any crawling, unattached ticks you might have missed.

During the full-body check, if you notice an attached tick, remove it promptly, (check out this useful tick key) and keep it. Store the tick in a well-sealed Ziploc bag and bring it with you to any doctor visits. Should medical professionals suspect disease transmission, the tick can be tested for confirmation.

Spider Bites

All spider bites are unwanted and painful, but there are a few species that arborists need to be especially aware of.

Many venomous spiders like to hide in dark, dry places like woodpiles and tend to nest low to the ground, making them a common hazard in the field. Paired with some impressive camouflage on their exoskeleton, they have a knack for going unnoticed before it’s too late.

“They can be in your boots, in your truck, and you won’t even realize it,” Thierbach said.

Brown Recluse

Hiding among the jobsite, arborists may come into contact with two hazardous spider species — the brown recluse and the black widow. Both are highly venomous and capable of delivering a serious bite.

The brown recluse spider (Loxosceles reclusa) is identified by its eight long legs and the violin-shaped marking on its head. These spiders aren’t generally aggressive but will bite when they feel threatened. Its venom is so toxic, it causes necrosis which can lead to skin ulcers if left untreated.

This spider subspecies is most active from April to October, with peak activity occurring in warmer spring and summer months. During this time, the brown recluse is highly active at night, hunting for food and mating. When winter rolls around, they hibernate or become dormant.

The brown recluse spider is most commonly found in the South Central and Midwestern parts of the United States, including Nebraska, Ohio, and Texas.

Symptoms of a Brown Recluse Spider Bite

Initially, most brown recluse bites are painless with symptoms developing hours later.

In about three to eight hours, a bite victim may experience the following:

• Mild redness and pain at the bite site
• Blistering
• A bull’s-eye pattern around the bite site
• An open ulcer that typically results in necrosis
• Fever and chills
• Gastrointestinal issues
• Muscle and joint pain

While most brown recluse spider bites heal without complications, seek medical attention if signs of infection develop, the wound becomes ulcerated or fails to heal, pain worsens, or you experience systemic symptoms such as fever, chills, nausea, or fatigue.

For more information, check out the Brown Recluse Spider Bite Information page from the Cleveland Clinic.

Black Widow

The black widow spider (Latrodectus) is often considered the deadliest and most dangerous spider in North America. It can be identified by its shiny black body with a distinctive red hourglass pattern on its belly. When a black widow bites, it releases a toxic venom that can cause severe pain, nausea, and, in rare cases, paralysis.

Black widows are most active during warmer months, with peak activity occurring during summer and early fall when temperatures are above 70℉. This is the optimal time for mating and egg-sac production. When temperatures drop, and winter settles in, the black widow generally goes dormant.

All arborists need to keep an eye out for this spider, as it lives and thrives throughout the entire United States, including Alaska.

Symptoms of a Black Widow Spider Bite

The powerful neurotoxins behind a black widow spider bite can directly affect the nervous system. Within about one to two hours, victims may experience:

• Swelling or rash at the bite location
• Intense muscle cramps
• Stomach and/or chest pain
• Unusually increased sweating
• Nausea
• Headache

If you suspect a black widow spider bite, the National Capital Poison Control Center recommends the following:

• Keep the affected area still. This prevents the venom from spreading faster throughout the body.
• Wash the bite site thoroughly with warm, soapy water and apply an icepack in 10-minute intervals.
• Seek emergency medical attention right away.

Black widow spider bites that are left untreated can cause flu-like symptoms, vital sign spikes, heart inflammation, and even death.

Tarantulas

Tarantulas may look intimidating, but these large, hairy spiders are much less dangerous than they appear. While they can bite and leave a significant wound, their venom is fairly low in toxicity and typically only results in localized pain and swelling.

But this doesn’t mean you shouldn’t keep an eye out for them. Tarantulas are nocturnal hunters, meaning they burrow during the day and emerge at night to hunt. They’re most active during warmer months — August through October — for mating season.

In the United States, tarantulas are commonly found in the Southwest and West, where the climate is consistently dry and warm. Arborists working in states like Arizona, California, New Mexico, Utah, and Texas, for example, may come face-to-face with these fairly docile creepy crawlers.

PPE Recommendations

The odds of all tree care workers coming into contact with spiders are pretty high. So, it’s best to wear proper PPE to significantly reduce the risk of harmful bites.

Consider using the following:

• Wear thick, puncture-resistant gloves while handling wood, debris, or reaching into tree cavities.
• Choose long sleeve shirts and thick chainsaw pants to cover exposed skin.
• Shake out gloves, helmets, and boots before and after every workday.
• Use a long stick to move debris —    never reach into a dark hole, woodpile or hollow space blindly.

Education is Key

Preventing and mitigating arachnid bite hazards starts and ends with education, regional wildlife research, and proper PPE on the job.

“I’ve been in this industry for about 35 years,” Thierbach said. “And honestly, the best thing a tree care company can do is educate their employees on wildlife hazards and the proper response to both stings and bites.”

For more information on Victoria Gardens’ webinars and educational seminars, visit vgtreecare.com.

Note: This article is for informational purposes only and should not be used for diagnosing or as medical advice. If you suspect a tickborne or spider bite-related illness, consult a physician immediately for accurate diagnosis and treatment.