Warm fall stretches won’t trigger Asian lady beetle invasions on their own, but they can make them more active and noticeable, especially when the insects are already looking for places to spend the winter.
You might have seen this odd sight on a warm afternoon in the late fall: dozens of Asian lady beetles, which look a lot like ladybugs, gathering on one wall while the rest of the house has almost none. The insects aren’t necessarily appearing because the warmer weather created a sudden population explosion. Rather, they were probably already inside and the weather happened to draw them out.
As fall progresses, adult Asian lady beetles look for places to overwinter. Sunlight can warm exterior siding considerably, even when the surrounding air is cool. South- and west-facing walls receive the most sun in the afternoon. That makes the beetles want to gather there. These warm stretches encourage beetles to fly, congregate on sunlit buildings, and seek potential shelter.
From there, small gaps around windows, doors, soffits, siding, and utility penetrations may provide access to wall voids or attics. That is when an outdoor gathering can become an indoor nuisance. Once inside, the beetles may remain relatively inactive through colder weather. Indoor heat or another warm spell can make them active again, sometimes causing beetles to appear around windows months after they originally entered. For the most part, the beetles don’t breed in the house. They get in as adults and overwinter while there.
Asian lady beetles can also release a yellowish defensive fluid when disturbed or crushed. The fluid may produce an unpleasant odor and stain some surfaces. Vacuuming visible insects can be less messy than crushing them against walls or curtains.
If you want to help prevent them from getting inside, you need to block the gaps they use to get in. To do this, repair damaged screens and deteriorated window seals. Look for small gaps around siding transitions and utility line penetrations and caulk them as appropriate.
If Asian lady beetles are gathering around or entering your North Central Minnesota home, Mosquito Squad can discuss appropriate pest management options, such as Squad Home Shield®. Call (218) 304-7704 or request a free quote online.
