The most effective midge sprays contain DEET or picaridin as their active ingredient, with DEET being the longest-studied option and picaridin offering comparable protection without damaging your gear. Biting midges (often called no-see-ums, sand flies, or gnats depending on where you live) are tiny enough to pass through standard mosquito netting, which means repellent choice matters even more than it does for larger insects.
DEET vs. Picaridin for Midges
DEET has been the go-to insect repellent for decades, and it works well against midges. Higher concentrations don’t repel more effectively, but they do last longer on your skin. A 20-30% DEET product will give you several hours of protection before you need to reapply. The downside is that DEET is a plasticizer. It can dissolve or damage certain synthetic materials, including coatings on sunglasses, headlamp lenses, and watch faces. It won’t weaken nylon or polyester fabric on its own, but blends containing rayon or spandex, or fabrics with specialty coatings, can break down on contact.
Picaridin (also sold under the names icaridin and saltidin) provides comparable repellency to DEET without the solvent issues. You can spray it on without worrying about your gear. A 20% picaridin formula offers solid, long-lasting midge protection and has become the preferred choice for hikers and campers who don’t want to think twice before handling equipment with treated hands. Both ingredients are available as pump sprays, aerosols, and lotions.
Natural and Plant-Based Options
Oil of lemon eucalyptus (OLE) is the strongest plant-derived repellent with formal recognition from the CDC. Its active compound, PMD, has been tested against mosquitoes and shown to provide protection similar to low-concentration DEET, but only during the first few minutes of exposure. After that initial window, it becomes significantly less effective. Commercial products with 8-10% PMD do list no-see-ums on their labels, so there is some real-world activity against midges, but you’ll need to reapply far more often than you would with DEET or picaridin.
Other natural repellents based on citronella, peppermint, or lemongrass exist in abundance, but testing consistently shows they require more frequent reapplication and often can’t match the performance of synthetic options. If you’re in an area with heavy midge pressure, like the Scottish Highlands in summer or a coastal marsh at dusk, natural sprays alone are unlikely to keep you comfortable.
Why Mesh Size Matters More Than You Think
Biting midges are small enough to fly straight through a standard mosquito net. A typical mosquito net has holes around 1.2mm across, which is plenty of space for a midge that measures well under 1mm. To physically block midges, you need a net with roughly 600 holes per square inch or more, which translates to holes of about 0.5mm or smaller. Some purpose-built midge nets go even finer, with densities above 800 holes per square inch.
The tradeoff is airflow. Finer mesh means less ventilation, which can make sleeping under a midge net feel stuffy in warm weather. If you’re camping in midge territory, look for nets specifically marketed for midges or no-see-ums rather than standard mosquito netting. Some people treat their finer mesh with permethrin (a contact insecticide applied to fabric, not skin) for an extra layer of defense. Combining a treated midge net with a skin-applied repellent is the most reliable approach in areas where midges are intense.
How to Apply Midge Spray Effectively
Midges target exposed skin, so the goal is complete coverage of any area that isn’t under clothing. Spray or rub repellent onto your ankles, wrists, neck, ears, and hairline, since midges are especially drawn to the head and face. If you’re using a spray on your face, apply it to your hands first and then rub it on, keeping it away from your eyes and mouth. Reapplication timing depends on the product: DEET and picaridin at 20% or higher can last several hours, while plant-based options may need refreshing every 30-60 minutes in heavy midge conditions.
Wearing long sleeves and pants in light colors reduces the amount of skin you need to treat. Midges are most active at dawn and dusk and in still, humid conditions. Wind is your best natural ally. Even a light breeze of 5-6 mph is enough to ground most midges, so positioning yourself in an exposed, breezy spot can be as effective as any spray.
Safety for Children and Pregnancy
The American Academy of Pediatrics recommends against using any insect repellent on babies younger than two months old. For those infants, clothing and fine-mesh netting are the only options. For children older than two months, DEET-based products are considered safe by both the CDC and the AAP, though the AAP recommends keeping concentrations at 30% or below. Don’t let young children apply repellent themselves, and avoid their hands entirely since kids frequently put their hands in their mouths. Wash treated skin as soon as you’re back indoors.
EPA-registered repellents containing DEET, picaridin, or oil of lemon eucalyptus are considered safe during pregnancy and breastfeeding. Studies tracking pregnant women who applied DEET regularly during their second and third trimesters found no harmful effects on mothers or their babies. Animal studies with picaridin similarly showed no effects on pregnancies or fetal development. In areas where insect-borne diseases are a concern, the CDC actively recommends that pregnant women use a registered repellent rather than go without.
Picking the Right Product
- For maximum protection: A 20-30% DEET or 20% picaridin spray gives the longest-lasting coverage against midges with the fewest reapplications.
- For gear-friendly use: Picaridin won’t damage plastics, coatings, or synthetic fabric blends, making it the better choice if you’re handling equipment while wearing repellent.
- For a natural option: Oil of lemon eucalyptus (10% PMD) is the most effective plant-based choice, but expect to reapply frequently and accept reduced protection compared to DEET or picaridin.
- For sleeping or stationary use: A fine-mesh midge net (600+ holes per square inch) treated with permethrin, combined with repellent on exposed skin, gives the most complete coverage.