Yes, though it's the Asian lady beetle, the invasive look-alike that swarms indoors in fall, rather than true ladybugs. When disturbed or crushed, they release a yellow defensive fluid that can stain light-colored walls, curtains, and furniture, and it carries a lingering odor.
You find yellowish smears on the windowsill or on the wall where the "ladybugs" gathered. They’re staining the walls and the upholstery and they smell awful. So you wonder: what’s that all about?
When an Asian lady beetle feels threatened, it releases a drop of yellow-orange fluid from its leg joints. The fluid smells foul and contains compounds that stain porous, light-colored surfaces. It's called reflex bleeding and it’s nature’s way of saying “don’t eat me, I taste bad!”
Light-painted walls, white trim, curtains, upholstery, and carpet are the most vulnerable. Smooth, dark, or sealed surfaces usually wipe clean without a mark.
The staining happens most in fall and winter, when the beetles cluster indoors to overwinter and then get disturbed, swatted or crushed against a surface, or vacuumed roughly.
Avoiding the stains mostly comes down to how you handle them. Don't swat or crush them, since that's exactly what triggers the fluid. Vacuum them gently instead, by slipping a stocking over a vacuum nozzle and securing it with a rubber band. This lets you capture the beetles without them touching the inside of the vacuum. Then you can release or dispose of them outside. Better still, act before they mass by sealing entry points in late summer so fewer get in to begin with.
If you do end up with a stain, blot it rather than rubbing, using mild soapy water or a vinegar solution as soon as you can. Older stains on porous surfaces can be stubborn, so the sooner you get to it, the better.
If you're tired of scrubbing yellow streaks off the walls every winter, Mosquito Squad of New Hampshire Lakes Region can help. Mosquito Squad offers perimeter treatments that help keep lady beetles and other fall invaders out. These are applied by a trained technician alongside the barrier service that delivers up to 90% reduction in mosquito activity on a 21-day cycle.
