To effectively get rid of black flies in Pennsylvania and New Jersey, you must combine immediate DIY tactics, such as setting up specialized CO2 traps and removing standing water, with long-term professional exclusion methods, such as upgrading to fine-mesh screening and applying biological larvicides.
Commonly referred to as house flies or cluster flies, black flies (Simuliidae) are aggressive, biting insects that can spread disease and severely impact quality of life if not properly managed.
While they are most prevalent in the Northeast during the summer, they can strike at any time, posing a genuine public health concern for residents in New Jersey and Pennsylvania.
Unlike standard nuisance flies, black flies are attracted to specific biological triggers; perfumes, moisture, and even the carbon dioxide in your breath can draw them toward your home. In our region, they are particularly common due to our extensive network of clean, fast-moving water sources like the Delaware and Susquehanna Rivers, which provide the oxygen-rich environments their larvae require to thrive.
The danger of these pests goes beyond a simple itch. Intense swarms can lead to “black fly fever,” a condition marked by headaches, nausea, and swollen lymph nodes caused by toxins in their saliva.
Additionally, their bites can trigger severe allergic reactions or respiratory distress in sensitive individuals.
Luckily, there are several options at your disposal to get rid of black flies, from common DIY tactics to professional-grade control. If you’re struggling with an infestation in your home, here is what you need to know to get rid of it.
What Are Black Flies in Pennsylvania and New Jersey?
Black flies (Simuliidae) are small, dark, biting insects that pose significant health risks and seasonal challenges for residents in New Jersey and Pennsylvania.
Often mistaken for common house flies or cluster flies, these pests pose a distinct public health concern due to their aggressive feeding habits and potential to transmit disease.
These small, biting gnats have a habit of hovering around wildlife, livestock, poultry, and, of course, us. They are blood-sucking creatures, not unlike mosquitoes, and, like their deadlier counterparts, black flies can carry diseases.
In extreme cases, biting swarms can transmit a disease known as “black fly fever” or cause skin swelling.
Why Are Black Flies So Common in NJ and PA?
There are 53 identified species of black flies in Pennsylvania and 40 in New Jersey alone.
In the Northeast, black flies are most active in spring and summer, though they can strike at any time and infest homes with abundant food sources.
The geography of the Mid-Atlantic region provides an ideal breeding ground for black fly populations for two primary reasons:
- Abundant Water Sources: Both states feature extensive networks of clean, fast-moving water, such as the Delaware and Susquehanna Rivers, which are required for black fly larval development.
- Water Quality Success: Ironically, improved water quality initiatives in these states have led to higher populations, as the larvae require oxygen-rich, unpolluted water to survive.
Homes near standing water, like retention ponds, rivers, and clogged gutters, will attract nearby black fly species, which could make their way indoors.
Why Do I Have So Many Black Flies
While black flies are often associated with poor sanitation, a dirty home is rarely the sole cause of an infestation.
Common attractants that draw these species toward or into your home include:
- Standing water inside your home (this can also attract several other insects).
- Decaying organic matter, such as compost, food scraps, and yard debris.
- Carbon dioxide emitted from your breath, as well as sweet-smelling perfume.
- Dark colors, including siding and furniture, catch the eye of these creatures.
What Are the Dangers of Black Flies?
Beyond being a persistent nuisance, black flies can significantly impact your quality of life through several serious health vectors. Because females require a blood meal to fertilize their eggs, they act as mechanical vectors for various pathogens and parasitic nematodes. While they are known for transmitting “river blindness” in certain tropical regions, the risks in North America are more localized but still severe:
- Black Fly Fever: Intense feeding from swarms can trigger black fly fever, a syndrome characterized by headaches, nausea, fever, and swollen lymph nodes. These symptoms are often exacerbated if the host suffers an allergic reaction.
- Allergic Reactions: The anticoagulants injected through a black fly’s saliva often cause “black fly bites,” resulting in intense itching and localized swelling. In hypersensitive individuals, this can lead to respiratory distress or anaphylactic shock.
- Threats to Livestock: These health risks are not limited to humans; parasites and toxic reactions can be transmitted to livestock as well. In extreme cases, massive swarms can actually suffocate pastured animals by clogging their nose and throat, or cause a fatal “toxic shock” syndrome.
- Nuisance and Irritation: Even non-biting species are problematic. These flies instinctively swarm the face, crawling into their targets’ eyes, ears, and mouths, making outdoor activities nearly impossible.
As annoying and dangerous as these pests can be, you want to avoid them if you can. Luckily, there are several options at your disposal to get rid of black flies, from common DIY tactics to professional-grade control. If you’re struggling with an infestation in your home, here is what you need to know.
7 Ways to Get Rid of Black Flies in Your House
While most people view black flies as simple nuisance bugs, their aggressive biting habits and potential for black fly fever make professional-grade exclusion and mitigation essential. Here are seven effective ways to control them:
1. Set Up Fly Traps
Black flies are highly visual and attracted to dark, moving objects. While standard apple cider vinegar traps work for fruit flies, black flies respond better to sticky traps or specialized CO2 traps. Place these near entry points like windows and doors to intercept adults before they reach living areas.
2. Remove Standing Water
Black fly larvae require flowing, oxygenated water. While they won’t breed in a stagnant puddle, they can thrive in clogged rain gutters, leaky outdoor faucets, or ornamental fountains with high aeration. Ensure all water features are treated or turned off during peak emergence seasons.
3. Fortify Home Entry Points
Because these flies are small (2–5 mm), they can easily pass through standard window screens. Upgrade to 20-mesh “no-see-um” screening to provide a physical barrier that standard mesh cannot provide. Ensure door weatherstripping is airtight to prevent doors from following CO2 trails indoors.
4. Optimize Landscaping for Airflow
Black flies are weak fliers and struggle in turbulent air. Use high-velocity outdoor fans on porches or near entryways to create a wind barrier. Additionally, keep vegetation trimmed back from the house; dense, shaded foliage provides the humid resting sites adult flies need to survive the midday heat.
5. Utilize EPA-Approved Repellents
For personal protection and perimeter defense, use repellents containing DEET, Picaridin, or IR3535. Studies from Rutgers University suggest that heavy applications of lemon eucalyptus oil may deter localized populations in NJ, though synthetic repellents remain the gold standard for biting species.
6. Neutralize Scent and Visual Attractants
Avoid wearing dark colors (blue, black, and red) during peak fly season, as these colors mimic the shadows of host animals. Additionally, switch to unscented personal care products. The floral notes in perfumes and soaps act as chemical beacons for S. jenningsi individuals seeking nectar sources.
7. Professional Larvicide Application (Bti)
The most effective way to control black flies at the source is through the use of Bacillus thuringiensis israelensis (Bti). While individual homeowners cannot treat large rivers, you can apply Bti-based donuts or granules to smaller on-property streams or drainage ditches to kill larvae without harming fish or other wildlife.
While the occasional black house fly is not a cause for alarm, if you’re noticing an uptick in house flies that are impacting your quality of life, contact The Pest Rangers. We offer preventative pest control programs that tackle black house flies, as well as organic insecticides that will temporarily keep them away from your home.
FAQs
How can I prevent black flies from entering my home?
To prevent black flies from entering your home, try these tips:
- Install fine mesh screens on windows and doors.
- Seal any cracks or gaps in windows, doors, and foundations.
- Use fly traps or deterrents near entry points.
- Keep garbage cans tightly sealed and dispose of organic waste properly.
What are natural ways to repel black flies?
If you are concerned about dangerous chemicals, some natural repellents you could try include:
- Essential oils like citronella, eucalyptus, or lavender.
- Wearing long sleeves and light-colored clothing.
- Planting fly-repelling plants like basil, mint, and marigold around your home or garden.
What insecticides can I use to control black flies?
Insecticides like pyrethrin-based sprays can help eliminate black flies. Use them with caution and follow the manufacturer’s instructions. Alternatively, you can use biological controls, such as Bacillus thuringiensis israelensis (BTI), which targets fly larvae in water sources.
When is black fly season in PA and NJ?
In Pennsylvania and New Jersey, black fly season typically peaks during the late spring and early summer (April through July). However, because they thrive in the clean, oxygen-rich waters of the Delaware and Susquehanna Rivers, localized “hatches” can occur anytime the weather stays consistently warm.
Do black flies actually bite, or are they just annoying?
Yes, female black flies are aggressive biters that require a blood meal to fertilize their eggs. Unlike mosquitoes that pierce the skin, black flies use saw-like mouthparts to cut the skin and lap up blood, which often results in painful, itchy welts and localized swelling.
Why are black flies attracted to me specifically?
Black flies are drawn to several biological and visual beacons. They are primarily attracted to the carbon dioxide (CO2) you exhale, as well as dark-colored clothing (like navy blue or black), and sweet-smelling attractants found in perfumes, soaps, and shampoos.
What is “Black Fly Fever”?
“Black fly fever” is a physical reaction to the toxins and anticoagulants found in a black fly’s saliva. If you are bitten by a large swarm, you may experience symptoms such as headaches, nausea, fever, and swollen lymph nodes. If symptoms become severe or cause respiratory distress, seek medical attention immediately.
