They look like ladybugs — until hundreds move into your walls each October.
When your home or office is overrun with what look like ladybugs, you're almost certainly dealing with the more aggressive Asian lady beetle. Every autumn across southern Wisconsin, these beetles abandon fields and leaf piles and gather in huge numbers on sunny building exteriors, working their way into window frames, siding cracks, attics and wall voids to spend the winter.
Store-bought ladybug pesticides are hard on your home and the environment — and rarely effective at this scale. Strib Pest Control offers comprehensive, environmentally friendly beetle control timed to stop the swarm before it gets inside.
Asian lady beetles range from tan to orange to red and may have many black spots or none at all — the most reliable marker is a black "M" shape on the white area behind the head. You'll find them congregating on:
Two more telltale signs: an unpleasant odor where they gather, and yellow staining on walls, curtains and sills from their defensive secretions.
Unlike native ladybugs, Asian lady beetles can pinch-bite when they land on skin — startling, though not dangerous. Their real offenses: the foul-smelling yellow fluid they secrete when threatened stains fabric, walls and window ledges and can trigger allergic reactions in sensitive people. And when thousands overwinter in a wall void, the winter-long trickle of beetles into your living space gets old very fast.
Timing is everything. We recommend scheduling service by late September or early October, just before the beetles begin swarming. Our exterior barrier treatment targets the sunny walls, eaves and entry points where beetles gather, dramatically reducing the number that make it inside. For commercial and industrial buildings — where large facades and countless crevices make DIY control impossible — we provide interior and exterior programs plus a structural vulnerability assessment.
Indoors, vacuuming is the best removal method (crushing causes stains and odor); we treat voids and entry areas to intercept beetles already in the structure.
If they are swarming your house in fall, biting occasionally and staining sills yellow, they are Asian lady beetles — an introduced species. Native ladybugs stay outdoors and do not overwinter in buildings in large numbers. Look for the black "M" marking behind the head.
Late September to early October, before they mass on your walls. An exterior barrier applied at the right time prevents most of the invasion. Once beetles are inside wall voids for winter, options narrow to interior management until spring.
They do not eat wood or fabric, but their yellow defensive secretion permanently stains curtains, walls and ledges, they emit a foul odor, and heavy indoor populations can aggravate allergies. Most clients simply want the winter-long invasion stopped — and it can be.
Fast, honest, guaranteed pest control across Madison and Dane County.
