No-see-ums: what actually works

Locals call them no-see-ums. The insects are biting midges in the family Ceratopogonidae, often Culicoides. University of Florida / IFAS describes them as tiny blood-feeders — many species around a millimeter long — abundant on coasts, miserable for anyone standing still at dawn or dusk near marsh, wrack, or damp organic sand. They also bite in shade when the air is dead calm. Wind helps. You cannot negotiate with them.

They are not mosquitoes. Standard 18×16 window screen does not stop them. A backyard mosquito fogger is not a custom midge program. If someone sold you a wristband and a miracle, keep the receipt.

What public-health sources actually recommend

CDC and EPA: use an EPA-registered skin repellent. Active ingredients that show up in that guidance for biting insects include DEET, picaridin, IR3535, oil of lemon eucalyptus / PMD, and 2-undecanone. Apply sunscreen first, repellent second. Reapply as the label says. Do not use oil of lemon eucalyptus / PMD on children under 3 unless a specific label allows it — read the bottle.

UF/IFAS on biting midges specifically: DEET-based repellents are the main products used against midges, with research showing DEET can reduce bites (Harrup et al. 2016, as cited in EENY-349). IFAS also notes that other products, including some essential oils, have data in particular species and regions — not a blank check for every grocery-store “natural” spray. A separate IFAS biting-fly sheet is blunter: most repellents work less well on biting flies than on mosquitoes, so you reapply more often, and moving air matters because these insects are weak fliers.

We are not going to crown picaridin “better than DEET for no-see-ums” as a law of nature. That claim is common in pest-control blogs. The extension documents we relied on still put DEET at the center for midges and list picaridin among EPA-registered options for mosquitoes and other arthropods. If picaridin sits better on your skin, it is a reasonable EPA-registered choice. If DEET is what you have, use it, at a concentration meant for hours outdoors, and reapply.

A stack that matches this coast

What to stop buying

• Ultrasonic plug-ins.
• Vitamin B1 and “mosquito pills.”
• Citronella jewelry.
• Essential-oil blends with no EPA registration, sold as if they were DEET. Some plant oils have lab data on some Culicoides species. That is not the same as a labeled, tested consumer product for Florida beaches.

Other Gulf biters, quickly

Salt-marsh mosquitoes after rain and king tides — same EPA-registered skin actives, plus dump standing water if you are at a house. Stable flies (the ones that bite ankles on the beach, often around wrack and rotting seaweed) are worse after wrack piles up; moving away from the wrack line helps more than a scented wipe. Deer flies inland at Blackwater in late spring are a hat-and-permethrin problem. See the Blackwater packing list.