May is when greenhead flies wake up on the Delmarva marsh edge, and they are not subtle about it. These are large, aggressive tabanid flies that slice the skin to feed, and the bites are immediately painful and itchy for days. They are most active on hot, still days, and they laugh at most repellents.
What it looks and feels like
- A sharp, immediate sting when the bite happens, followed by a large raised welt within minutes.
- The bite site often bleeds slightly because greenheads cut the skin rather than pierce it like a mosquito.
- Itch and soreness last 3 to 7 days; scratched welts can scab and scar if you keep picking.
What to do right now
- Wear light-colored, long-sleeve clothing - greenheads are attracted to dark moving shapes.
- Avoid marsh edges and still, humid pockets of air between 10 a.m. and 4 p.m. on calm days.
- Standard DEET and picaridin sprays only help a little; a physical barrier like a loose button-down over a tee shirt works better.
- If you get bitten: ice for 10 minutes, then 1% hydrocortisone or calamine. An oral antihistamine at night helps with the itch.
- Keep fingernails short and cover the bite with a small bandage if you cannot stop scratching.
Local note
On Delmarva, greenheads are worst in the salt marsh areas around Assawoman Wildlife Area, the Blackwater National Wildlife Refuge edges, and the marshy stretches of the Indian River Inlet. The ocean-side surf at Rehoboth or Ocean City is usually safe - greenheads prefer still, marshy air.
Cover up, stay breezy. See you in June.
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