Spring is here — and if you've spent any time at the barn lately, you already know what that means. The bugs are back. And not just the big, obvious ones you can swat away. The tiny ones — the no-see-ums, gnats, and midges you can barely see — are often the ones causing the most damage.
Every year, horse owners scramble to protect their animals once biting insects are already in full force. But by then, the itching, rubbing, and skin irritation have already started. The key is understanding what you're dealing with and getting ahead of it before the worst of the season hits.
Here's everything you need to know.
What Are No-See-Ums?
No-see-ums — technically called Culicoides midges — are tiny biting insects that are so small you often can't see them landing on your horse. Don't let the size fool you. These bugs are aggressive feeders, and they tend to swarm, which means your horse isn't dealing with one bite — they're dealing with dozens or even hundreds at a time.
They're most active during the warmer months, especially spring through early fall, and they tend to peak around dawn and dusk. They thrive in warm, moist environments — near standing water, marshy areas, manure piles, and anywhere with poor airflow.
What makes them especially problematic is that horses produce octenol in their sweat and urine, which actively attracts these insects. Your horse isn't just an accidental target — they're a magnet.
Common Biting Insects That Affect Horses
No-see-ums get a lot of the attention, but they're not the only ones making your horse miserable. Here are the main culprits during spring and summer:
Culicoides midges (no-see-ums) are the smallest and often the worst offenders. They target the mane, tail, belly, and ears — anywhere the skin is thinner or has less hair coverage.
Mosquitoes are most active at dawn and dusk, similar to midges. Beyond the irritation, they can transmit serious diseases like West Nile Virus and Eastern Equine Encephalitis.
Horse flies and deer flies deliver painful bites that can cause significant swelling and bleeding. They're aggressive daytime feeders and are especially active near wooded areas and water.
Gnats and black flies tend to swarm around the face, ears, and eyes. They feed on blood and can cause crusty, irritated skin around those areas.
Stable flies look like house flies but bite — hard. They favor the legs and lower body and are common around barns where manure and wet bedding accumulate.
Signs Your Horse Is Being Affected
Sometimes the bites themselves are hard to spot, especially with no-see-ums. But your horse will tell you something is wrong. Watch for:
Excessive rubbing of the mane and tail — to the point of hair loss and raw, broken skin. Stomping, tail swishing, and general restlessness that goes beyond normal behavior. Patchy hair loss, especially along the mane, tail base, belly, and chest. Flaky, scaly skin or small oozing lesions in areas where insects tend to feed. Head shaking and ear twitching, especially if gnats and black flies are targeting the face. And in more severe cases, thickened or cracked skin from repeated biting and scratching — a condition many horse owners know as sweet itch.
If your horse is showing these signs and it's spring or summer, biting insects should be the first thing on your radar.
How to Protect Your Horse Naturally
You don't need to drench your horse in harsh chemicals to keep bugs at bay. Here's a multi-layered approach that actually works:
Manage the Environment First
Start at the source. Eliminate or reduce standing water around your property — that's where midges and mosquitoes breed. Keep manure picked up regularly, especially in turnout areas and near the barn. Improve airflow in stalls and run-in sheds with fans — even a consistent breeze makes it significantly harder for small flying insects like no-see-ums to land and feed.
Use Physical Barriers
Fly sheets, fly masks, and belly bands are some of the most effective tools you have. A well-fitted fly sheet with belly coverage protects the areas midges target most. Fly masks with ear covers protect against gnats and black flies that swarm the face. For horses that are especially sensitive, lightweight leg wraps or fly boots can help too.
Time Your Turnout Strategically
Since no-see-ums and mosquitoes are most active at dawn and dusk, adjusting your turnout schedule can make a real difference. If possible, bring horses in during peak feeding times and turn them out during the middle of the day when these insects are less active.
Apply a Natural Insect Repellent
Look for oil-based coat sprays made with ingredients that insects naturally avoid — things like neem oil, rosemary, citronella, and lemongrass. Oil-based formulas tend to last longer on the coat compared to water-based sprays because they don't evaporate as quickly and they condition the skin while they're working.
The key is consistency. One application when you remember it isn't enough. Make it part of your daily or every-other-day routine, especially during peak season. Focus on the areas bugs target most — the mane line, tail base, belly, inner legs, and around the ears.
Support Healthy Skin From the Outside In
A horse with healthy, well-conditioned skin handles insect pressure better than one with dry, irritated skin. Regular grooming helps you catch early signs of irritation before they become bigger problems. Keeping the coat clean and conditioned creates a better barrier against biting insects and reduces the chance of secondary skin issues from scratching.
When to Be Concerned
Most insect-related irritation can be managed with consistent prevention and good environmental practices. But if your horse is showing signs of severe itching, open wounds from rubbing, or widespread hair loss that isn't improving, it's time to involve your veterinarian. Some horses develop Culicoides hypersensitivity — an allergic reaction to midge saliva that requires more targeted support.
The important thing is not to wait until things escalate. The earlier you address insect pressure, the easier it is to keep your horse comfortable and healthy through the season.
Stay Ahead of the Season
The biggest mistake horse owners make is waiting until the bugs are already bad to start taking action. The best time to put your prevention plan in place? Right now. Clean up the environment, get your fly gear ready, and start applying a quality natural coat spray before the worst of the season arrives.
Your horse will thank you.
At The Botanical Horse, we make oil-based, botanical coat sprays designed to help keep horses comfortable during insect season — without harsh chemicals. [Explore our No-See-Um Coat Spray here.]
Frequently Asked Questions About No-See-Ums and Horses
What time of day are no-see-ums most active?
No-see-ums are most active at dawn and dusk when the air is still and humidity is higher. They tend to avoid strong sunlight and wind, which is why improving airflow in stalls and turnout areas can make a real difference.
Can no-see-ums bite through fly sheets?
Standard fly sheets may not be enough. No-see-ums are extremely small and can get through loosely woven materials. Look for fine-mesh sheets specifically designed for midges, and pair them with a natural coat spray like No-See-Um Coat Spray for added protection.
What should I do if my horse already has skin damage from biting insects?
If your horse has raw, irritated, or broken skin from scratching or bites, focus on soothing and protecting the area. Restorative Clay can help calm inflamed skin and support natural healing. For areas prone to moisture and fungal issues, Restorative Powder provides a talc-free, anti-fungal barrier that keeps the skin dry and protected.
Are no-see-ums the same thing as gnats?
Not exactly. No-see-ums are a specific type of biting midge (Culicoides), while "gnats" is a broader term that includes black flies and other small flying insects. The key difference is that no-see-ums are often the primary trigger for sweet itch in horses.
Related Reading
Want to go deeper on the conditions biting insects cause? Check out these guides:
Sweet Itch in Horses: What It Is and Natural Ways to Manage It
Why Is My Horse Rubbing Its Mane and Tail? Causes & Solutions
