Large Brown Ladybug-like Beetle in UK: Asian/Harlequin Lady Beetle, Exclusion and Vacuuming

UK homeowner sees large brown/black ladybug-like beetles entering through window gaps, emit foul smell when squashed. Asks for ID and deterrent.

Expert Response

Likely Asian or Harlequin lady beetles. Management: vacuuming (use handkerchief to trap for release), seal entry points (caulk, 1/8" gaps), exterior insecticide treatments in fall (lambda-cyhalothrin, deltamethrin, bifenthrin, cyfluthrin). Over-the-counter: Spectracide Triazicide, Bayer Advanced, Ortho Home Defense Max. No quick fix; combination of methods needed.