Asian stink bugs seek indoor shelter as daylight decreases

Asian stink bugs (Halyomorpha halys) begin seeking shelter for the winter even before temperatures drop, triggered by decreasing daylight hours. When daily light falls below 13.5 hours—typically between late August and September—these insects start searching for sun-exposed surfaces and sheltered areas to overwinter.

Residential buildings often serve as ideal refuges. Once inside, they can remain hidden for long periods, reappearing when indoor heating disrupts their dormancy. To prevent infestations, homeowners are advised to seal small openings, specifically checking roller shutter boxes, window seals, and ventilation grilles. Protecting air vents with fine mesh is recommended to block entry without obstructing airflow.