Colorado’s high-altitude landscapes host unique biting insects like the Rocky Mountain wood tick. Understanding the common biting insects in Colorado is essential for anyone who spends time outdoors here, from hikers to backyard gardeners.
This guide covers the main species you’ll encounter, their habits, and practical ways to avoid bites. We’ll keep it straightfoward and useful, so you can enjoy Colorado’s beauty without the itch or worry.
Biting Insects In Colorado: An Overview
Colorado’s diverse ecosystems—from plains to alpine tundra—support a variety of biting insects. Some are just nuisances, while others can transmit diseases. Knowing what you’re up against is the first step to staying protected.
We’ll break down the most common types, where they live, and when they’re most active. This way, you can plan your outdoor adventures with confidence.
Mosquitoes In Colorado
Mosquitoes are perhaps the most widespread biting insects in Colorado. They breed in standing water, from mountain ponds to urban bird baths. The state has over 50 species, but only a few are aggressive biters.
Peak mosquito season runs from late spring through early fall. They are most active at dawn and dusk. Some species, like the Aedes vexans, can travel miles from breeding sites.
Disease Risks From Mosquitoes
While rare in Colorado, mosquitoes can carry West Nile virus. The state reports cases most years, especially in warmer months. Other diseases like Zika or dengue are not locally transmitted here.
To reduce risk, use EPA-approved repellents like DEET or picaridin. Remove standing water around your home. Wear long sleeves and pants during peak hours.
Ticks: The Rocky Mountain Wood Tick
The Rocky Mountain wood tick is the most common tick species in Colorado. It thrives in grassy, brushy areas at elevations up to 10,000 feet. Adult ticks are most active from March to July.
These ticks can transmit Colorado tick fever, a viral illness with flu-like symptoms. They can also cause tick paralysis in rare cases. Unlike some other states, Lyme disease is not common in Colorado.
How To Avoid Tick Bites
Stick to trails and avoid tall grass. Tuck pants into socks and shirts into pants. Do a full body check after being outdoors, especially in hair and behind knees.
If you find a tick attached, remove it with fine-tipped tweezers. Grasp close to the skin and pull upward steadily. Clean the bite area with soap and water.
Black Flies (Buffalo Gnats)
Black flies are small, hump-backed insects that bite aggressively. They are common near fast-moving streams and rivers in Colorado’s mountains. Their bites can be painful and cause swelling.
Black flies are most active during late spring and early summer. They tend to bite during the day, especially in cloudy conditions. They are attracted to dark clothing and carbon dioxide.
Repellents containing DEET work, but black flies are less deterred than mosquitoes. Wearing light-colored clothing and a hat with a net can help. Avoid areas near water during peak activity.
Horse Flies And Deer Flies
These large, noisy flies are common in Colorado’s wetlands and near livestock. Horse flies are bigger and have patterned eyes. Deer flies are smaller with dark bands on their wings.
Both are day biters and attracted to movement and dark colors. Their bites are painful because they slice the skin to feed. They can cause allergic reactions in some people.
Protection includes wearing long sleeves and using repellents with DEET or permethrin on clothing. Traps and fans can help reduce numbers around your home.
Biting Midges (No-See-Ums)
Biting midges are tiny, barely visible insects that pack a painful bite. They are found near moist areas like marshes, lakes, and even irrigated lawns. They are most active at dawn and dusk.
Their bites cause intense itching and welts. They can penetrate screens and clothing. Repellents with DEET or oil of lemon eucalyptus can help.
Using fine-mesh screens and avoiding outdoor activity during peak times reduces exposure. Fans can also keep them away because they are weak fliers.
Prevention Strategies For Biting Insects In Colorado
Now that you know the main players, let’s talk about prevention. A few simple steps can make a big difference in your comfort and safety.
Choose The Right Repellent
Not all repellents are equal. For mosquitoes and ticks, DEET (20-30%) is highly effective. Picaridin is a good alternative with less odor. Permethrin is for clothing only, not skin.
For black flies and midges, higher concentrations of DEET work better. Oil of lemon eucalyptus is a natural option but needs reapplication more often.
Always follow label instructions. Apply repellent after sunscreen. Wash it off when you come indoors.
Dress For Protection
Covering up is your first line of defense. Wear long sleeves, long pants, and closed-toe shoes. Light-colored clothing makes ticks and flies easier to spot.
Tuck pants into socks and shirts into pants when in tick areas. Consider clothing pre-treated with permethrin for added protection.
Hats with nets are useful in heavy fly areas. Avoid dark colors that attract horse flies and black flies.
Manage Your Environment
Around your home, eliminate standing water where mosquitoes breed. Clean gutters, empty plant saucers, and change bird baths weekly. Keep grass mowed and brush trimmed.
For ticks, create a barrier between your yard and wooded areas with gravel or wood chips. Keep play areas away from tall grass.
Use outdoor fans on patios to keep biting flies away. They are weak fliers and avoid moving air.
Time Your Activities
Mosquitoes are most active at dawn and dusk. Black flies and horse flies bite during the day. Plan your outdoor time accordingly.
If you must be out during peak times, take extra precautions. Reapply repellent and check for ticks afterward.
Midday sun can reduce mosquito activity but not horse flies. Adjust your schedule based on the insects you’re most concerned about.
Treatment For Bites
Even with prevention, bites happen. Here’s how to handle them.
Immediate Care
Wash the bite area with soap and water. Apply a cold pack to reduce swelling. Avoid scratching to prevent infection.
Over-the-counter antihistamines like diphenhydramine can relieve itching. Calamine lotion or hydrocortisone cream also helps.
For tick bites, monitor the area for a rash or fever. If symptoms develop, see a doctor.
When To See A Doctor
Seek medical help if you have signs of an allergic reaction: difficulty breathing, swelling of the face or throat, or hives. Also see a doctor if a bite becomes infected—redness, warmth, or pus.
For tick bites, watch for fever, headache, or muscle aches within two weeks. These could be signs of Colorado tick fever or other illnesses.
Mosquito bites rarely need medical attention unless you develop West Nile virus symptoms: high fever, severe headache, or confusion.
Frequently Asked Questions
What Is The Most Common Biting Insect In Colorado?
Mosquitoes are the most widespread, but the Rocky Mountain wood tick is the most common tick species. Both are encountered frequently by residents and visitors.
Are There Dangerous Biting Insects In Colorado?
Most bites are just annoying, but some insects can transmit diseases. Mosquitoes can carry West Nile virus, and ticks can carry Colorado tick fever. The risk is low but worth taking seriously.
When Is Biting Insect Season In Colorado?
It varies by species. Mosquitoes are active from May to September. Ticks peak from March to July. Black flies are worst in late spring and early summer. Horse flies are around from June to August.
What Repellent Works Best For Colorado Insects?
DEET (20-30%) is effective for mosquitoes, ticks, and flies. Picaridin is a good alternative. Permethrin on clothing adds extra protection. For natural options, oil of lemon eucalyptus works for mosquitoes.
Can I Get Lyme Disease From Ticks In Colorado?
Lyme disease is extremely rare in Colorado. The western black-legged tick, which carries Lyme, is uncommon here. The Rocky Mountain wood tick does not transmit Lyme disease.
Staying informed about biting insects in Colorado helps you enjoy the outdoors safely. With the right precautions, you can minimize bites and focus on the stunning landscapes this state offers. Remember to check for ticks, use repellent, and time your activities wisely. A little planning goes a long way toward a comfortable outdoor experience.