Lady beetle infestation of buildings is a sporadic event. In the natural world, their overwintering sites are nooks and crannies inside the hollows of trees. Our homes serve as substitute trees. Some buildings are affected, others are not. Generally, light-colored buildings near forested land are more likely to experience an invasion.

During the summer, the Asian lady beetles feed on aphids and other small insects living in the trees and fields in the area. From that perspective, the lady beetles are beneficial creatures. But when they enter our homes, they cross the line from being beneficial to being a nuisance. Fortunately, there are no major health problems associated with the Asian lady beetle.

To keep them out of your home, exterior cracks and other openings can be sealed as a preventive measure. Use a good-quality silicone or silicone latex caulk to seal cracks around windows, doors, siding, fascia boards, utility pipes, and other potential entry points. Repair damaged window screens and install insect screening behind attic vents.

While sealing and weather stripping can help limit the entry of lady beetles, this approach is time consuming and often impractical. There are countless numbers of cracks under and around eaves, siding, vents, etc., where beetles can enter. On multistory buildings, sealing becomes extremely difficult. Households or businesses that do not wish to chance a recurring problem with overwintering lady beetles may want to enlist the services of a knowledgeable pest control firm or garden center.

There are several insecticide treatments available for the building exterior that help prevent pest entry. Long-lasting, rapid knockdown formulations of insecticides can be applied around eaves, attic vents, windows, siding, and other likely points of entry. The key is to apply the treatments in early October, before pests enter buildings. Once they enter the building, a vacuum cleaner is the best control option.