Asian Beetles in New Hampshire

Both: a genuinely effective aphid predator and a documented invasive displacing native ladybugs. An adult eats 90-270 aphids daily, yet still displaces natives.

Structurally, essentially none — no wiring damage, no fabric infestation, no wood-boring. The one real effect is a cosmetic yellow stain, not structural harm.

"Ladybug" and "Asian beetle" are two names for one insect. The one clustering on a New Hampshire house each fall is essentially always the Asian lady beetle.

The odor and the yellow stain are the same event: reflex bleeding. Disturbed beetles release hemolymph that smells foul and can stain light surfaces.

They're dormant, not hibernating: a fat-fueled diapause, empty gut, stored fat. Warm days rouse a few toward windows — last fall's cohort, not newcomers.

Sticky traps snag a few boxelder bugs and lady beetles, but extension research shows light traps catch relatively few — vacuuming and sealing do more.

Yes, actually: Asian lady beetles nip, reflex-bleed a staining fluid, and are a documented indoor allergen. This is the one fall-invader fear that's true.

Asian lady beetles swarm sunny NH walls on warm October days, then overwinter in wall voids. They don't breed or damage homes — see the month-by-month timing.

Yes. Asian lady beetles seek shelter before the first hard frost and overwinter as dormant adults in wall voids, they are not breeding behind your walls.

Caulking siding gaps of about an eighth of an inch keeps lady beetles out before late September, though loosely-hung siding can limit a truly complete seal.