The Adirondack region in upstate New York is a haven for outdoor enthusiasts, offering breathtaking landscapes, serene lakes, and abundant wildlife. However, one nasty adversary can put a damper on your outdoor adventures: black flies. These tiny, bloodthirsty insects are notorious for their relentless swarming and biting, causing discomfort and annoyance for our visitors. Here’s a quick guide to help you navigate the black fly season in the Adirondacks, so you can enjoy our wonderful area.

Photo credit: D. Sikes (CC BY-SA 2.0)

Black flies, scientifically known as Simuliidae, are a type of small, blood-feeding insect belonging to the family Simuliidae within the order Diptera (flies). They are commonly found in various parts of the world, including North America, Europe, and parts of Africa. In the Adirondacks specifically, black flies can be a prominent feature of the local insect population.

Here are some key characteristics of black flies:

1. Size and Appearance. Black flies are relatively small insects, typically measuring between 1 to 5 millimeters in length. They are dark in color, hence their name, but can also have a gray or greenish hue. Black flies have a robust body structure, with six legs, a pair of wings, and a pair of antennae.
2. Biting Behavior. Black flies are known for their biting habits, with females being the ones that require a blood meal to reproduce. They possess specialized mouthparts that allow them to puncture the skin and feed on the blood of mammals, birds, and sometimes reptiles. Male black flies, on the other hand, primarily feed on nectar and plant juices.
3. Habitat and Lifecycle. Black flies are typically found near bodies of water, such as rivers, streams, and lakes, as they require clean flowing water for their larvae to develop. Females deposit their eggs on the surface of water or on objects near the water, such as rocks or vegetation. The eggs hatch into aquatic larvae, commonly known as “black fly maggots,” which attach themselves to submerged surfaces and feed on organic matter. After several stages of development, the larvae transform into pupae and eventually emerge as adult flies.
4. Seasonal Occurrence. In the Adirondacks, black flies are most prevalent during the spring and early summer, typically from late May to early July. This period is often referred to as the “black fly season.” The emergence of black flies is influenced by factors such as temperature, humidity, and water conditions. They are known to be active during daylight hours, particularly during the early morning and late afternoon.
5. Impact on Humans and Wildlife. Black flies are considered nuisance insects due to their painful bites and swarming behavior. The bites can cause itching, swelling, and discomfort in humans, often leading to irritation and potential allergic reactions in some individuals. In areas with high black fly populations, wildlife and livestock may also be affected, with bites leading to reduced productivity and annoyance. However, it’s important to note that despite their annoyance, black flies also play a role in ecosystems as a food source for certain birds and other insect-eating organisms.

Photo Credit: Black Fly larvae in river by GlacierNPS (CC PDM 1.0)

In the Adirondacks, black flies are typically found in areas of dense vegetation and will swarm in sheltered and shaded areas with high moisture. These places include lakes and pond inlets as well as streams and rivers as their larvae require clean, fast-moving water to develop. This is also because fungi grow in these areas where black flies like to lay their eggs. It is best to avoid these places if at all possible during their breeding season.

Here are some common black fly habitats you may encounter in the Adirondacks:

1. Rivers and Streams. Black flies are commonly found along the banks of rivers and streams. The swift-flowing water provides an ideal environment for their larvae, which attach themselves to submerged rocks, vegetation, or other surfaces. Hiking trails that run parallel to rivers or cross over streams may have higher black fly activity, especially during the peak season.
2. Lakes and Ponds. While black flies are more associated with flowing water, they can also be present near lakes and ponds in the Adirondacks. Areas around the shoreline, especially where there are inflowing or outflowing streams, can be prone to black fly populations. Campsites near water bodies may experience higher black fly activity, particularly during the early morning and late afternoon.
3. Wetland Areas. Wetlands, such as marshes, bogs, and swamps, are favorable habitats for black flies. The combination of stagnant or slow-moving water and abundant vegetation provides an ideal breeding ground for black fly larvae. Hiking or exploring trails that traverse wetland areas may expose visitors to increased black fly activity.
4. Wooded Areas. Black flies are known to inhabit wooded areas, especially those close to water sources. They seek shaded spots and areas with dense vegetation, such as forests and tree canopies. While hiking or camping in wooded areas, particularly near rivers or lakes, visitors may encounter black flies.
5. Waterfalls and Cascades. Black flies can be particularly abundant near waterfalls and cascades in the Adirondacks. The mist and spray generated by the falling water create a damp environment, attracting black flies. Visitors enjoying the scenic beauty of waterfalls should be prepared for increased black fly activity in these areas.

It’s important to note that black fly habitats can vary depending on factors such as water availability, temperature, and local conditions. Understanding their preferred environments can help you plan your outdoor activities accordingly and take appropriate precautions to mitigate the impact of black flies.

The black fly season in the Adirondacks typically occurs during the spring and early summer months. While the exact timing can vary based on weather conditions and specific locations, the peak black fly season in our area generally spans from late May to early July. This is when black flies are most abundant and active in the region.

It’s worth noting that the intensity and duration of the black fly season can vary from year to year, influenced by factors such as temperature fluctuations, precipitation, and water conditions.

Keep in mind that black flies can still be present outside of the peak season, especially during periods of favorable weather.

Black flies are attracted to humans by a combination of factors, including visual cues, body heat, movement, and the release of certain chemicals. Understanding what attracts black flies can help individuals take preventative measures to reduce their attractiveness and minimize encounters. Here are some factors that attract black flies to humans:

1. Carbon Dioxide. Black flies are attracted to the carbon dioxide we exhale. They have specialized sensory organs that can detect the presence of carbon dioxide, which signals the presence of a potential host.
2. Body Heat and Moisture. Black flies are drawn to body heat and moisture. When we are active or engaged in physical exertion, our bodies generate more heat and moisture, making us more attractive to black flies. Sweat, in particular, can attract these insects.
3. Movement and Contrast. Black flies are attracted to movement and high-contrast visual patterns. Rapid movement can signal potential prey to these insects. Additionally, dark-colored clothing or contrasting patterns can make individuals more visible and attractive to black flies.
4. Scent and Chemicals. Black flies are sensitive to certain scents and chemicals that humans emit. They are attracted to compounds such as lactic acid, ammonia, and certain types of bacteria that naturally occur on our skin. These compounds can vary between individuals, which is why some people may be more attractive to black flies than others.
5. Skin Temperature and Color. Black flies are known to prefer areas of the body where the skin temperature is slightly cooler, such as the lower legs and ankles. They are also attracted to darker colors, so wearing dark-colored clothing may make individuals more appealing to these insects.

It’s important to note that while certain factors can make individuals more attractive to black flies, the degree of attraction can vary between individuals. Some people may be more prone to black fly bites due to their unique body chemistry, while others may have less of an attraction.

To minimize attraction and reduce black fly bites, individuals can take preventive measures such as wearing light-colored clothing, covering exposed skin with loose-fitting clothing, using insect repellents, and avoiding outdoor activities during peak black fly hours.

While it may be challenging to completely eliminate black fly attraction, these preventive measures can help reduce the likelihood of being bitten and provide some relief when exploring areas with black fly populations.

Black flies typically target exposed areas of the body, especially areas with thinner skin and easy access to blood vessels. While preferences may vary between individual black fly species, there are certain body parts that tend to be more attractive to these insects. Here are the body parts that black flies are known to target most frequently:

1. Head, Face, and Neck. The head, face, and neck are prime targets for black flies. They are particularly attracted to the warmth, moisture, and carbon dioxide emitted from the breath and skin in these areas. The area around the ears, hairline, and back of the neck is commonly bitten.
2. Lower Legs and Ankles. Black flies are often drawn to the lower legs and ankles. These areas are easily accessible to the insects and have cooler skin temperatures compared to other parts of the body. Bites around the ankles and calves are common, especially when individuals are wearing shorts or skirts.
3. Arms and Hands. Exposed areas of the arms, including the forearms and hands, are also susceptible to black fly bites. As with other body parts, black flies are attracted to the warmth and movement of these areas. Bites on the hands and wrists can occur when individuals are engaged in outdoor activities or when sitting near black fly habitats.
4. Back and Shoulders. Although not as frequently targeted as the head, neck, and limbs, black flies may bite the back and shoulders, especially if these areas are exposed. This can happen when individuals are wearing sleeveless shirts or have their upper back exposed while wearing backpacks or carrying gear.

It’s important to note that black fly preferences can vary, and individual reactions to bites can also differ. Some people may experience more bites on specific body parts due to their unique body chemistry or attractants. Additionally, black flies can bite through thin clothing, so taking appropriate measures to protect exposed areas is essential.

When venturing into black fly-infested areas, consider wearing protective clothing, such as long-sleeved shirts, long pants, and socks. Applying insect repellents to exposed skin and using physical barriers like head nets can also help reduce black fly bites on vulnerable body parts.

By taking preventative measures and being aware of the areas that black flies are most attracted to, individuals can minimize the discomfort and annoyance caused by these persistent insects.

Photo Credit: Pesce Huang

1. Protect Your Skin. If you do go out, make sure to protect your skin with light-colored clothing that covers as much of your skin as possible. Since black flies often go for the hairline and the back of your neck, it can be tough to protect yourself effectively. Wear loose-fitting clothing and hats with netting when you know these pests are active.
2. Use a Repellent. If you’re going to use bug spray, avoid sprays with DEET and opt for sprays with Picaridin. Picaridin is a compound bioidentical to those found in long black pepper plants and sprays using this are safer on skin compared to other options. Stay Away® Mosquitoes is an insect repellent that uses Picaridin as the active ingredient and can work to repel black flies.
3. Apple Cider Vinegar. Since we know it’s sweat and sweet scents that attract these pests, we need to make sure that our sweat won’t be on the menu. If you know you’re going to be in a place with mosquitos or black flies, consider drinking apple cider vinegar mixed into your water which can help make you less attractive to these pests.
4. Keep Cool and Dry. It may seem obvious, but not sweating will give you the best chance at not attracting black flies. Keeping your body cool and dry will not only make you more comfortable outside, but you will also reduce the chances of experiencing a painful bite.
5. Essential Oils. There are certain scents that pests simply hate including mint, peppermint, and lemongrass. Using these essential oils can help keep pests away and peppermint can also provide a bit of relief for a bug bite!

1. Dress Appropriately. Wear light-colored, long-sleeved shirts, long pants, and socks to minimize exposed skin. Tuck your pants into your socks and choose footwear that covers your feet well. Opt for lightweight and breathable clothing to stay comfortable on your hike.
2. Protect Your Head and Neck. Wear a hat with a wide brim to shield your face and neck from black flies. Consider using a head net made of fine mesh that covers your entire head, neck, and shoulders for additional protection. There are some versions of a head net that let you keep your hat inside the netting, to keep the net off of your head. This will help.