The Autumn Beetle Home Invasion in Custom Homes: Luxury Custom Built Homes Are Targets Too

The end of summer is the beginning of an unwelcome invasion by Asian Lady Beetles, considered the “bad” ladybug by many homeowners. As autumn approaches, adult beetles leave summer feeding sites in yards, fields and forests in search of protected places to spend their winter. Swarms typically fly to buildings and homes beginning in September in search of overwintering sites, ending up indoors and crawling on walls or windows or flying around the room and landing on furniture. Even newly constructed luxury homes can be a target for these pests, whose mere presence is offensive enough, yet also emit a noxious smell when squashed, adding insult to injury.

The Asian Lady Beetle is sometimes mistakenly called a Japanese Beetle, which is an entirely different nuisance to Wisconsin.  The Japanese Beetle was first found in the United States in 1916, accidentally introduced as grubs living on the soil of the roots of an imported Japanese Iris. It proved to be a hearty and prolific breeder, spreading quickly to all states east of the Mississippi, wreaking havoc on carefully cultivated landscaping and causing monumental damage to crops each year. The grubs cause dead patches of lawn by chewing off grass roots while adults feed on the foliage. The adult beetles tend to emerge in July and have a 60-day lifespan.

In contrast, the Asian Lady Beetle is the pest that closely resembles the benign ladybug native to North America. The Asian Lady Beetle is however aggressive, can bite or pinch when it lands on skin and congregates in large numbers. In terms of appearance, the Asian species’ color ranges from light tan or orange to bright red (like the ladybug), with spots that vary from dark black to light. The true identifier is a white marking behind its head in the opening of what looks like a black “M”. Unlike the Japanese Beetle, the Asian Lady does not feed on plants; it feeds on aphids and scale insects and was purposely introduced by the USDA in select states of the country (such as Georgia, Louisiana and South Carolina) around 1960 to control these agricultural pests. They have migrated to nearly every state since, which was likely facilitated by accidental introduction via freighters.

The not so beneficial by-product of their introduction is their tendency towards “home invasion” this time of year. They congregate in huge numbers, and the flights of these swarms are heaviest on sunny days, following a period of cooler weather, which is a nuisance to those enjoying the outdoors on Wisconsin’s welcome Indian Summer days in September. The Asian Ladies are attracted to illuminated surfaces, thus congregating on the sunnier, southwest sides of buildings that are lit by the afternoon sun. Once they land on a building or even newly constructed luxury home, they will seek out any crevice to allow a protected location for the winter, typically cracks around window and doorframes, behind exterior siding and within attics and wall voids. Homes near fields and woods are more prone to infestation, as are those older homes in poor repair with many cracks and openings.

The good news for concerned homeowners is that the Asian Lady Beetle does not transmit any disease, nor do they attack clothing, food or wood. They are hibernating for the winter and during this time they do not reproduce indoors; the same beetle that enters the home in the autumn becomes active again in the spring and seeks to return outdoors. In their attempt, many inadvertently wander inwards and emerge once again in the spring from behind baseboards, walls and attics and congregate by windows and light fixtures due to their attraction to light. Affected homeowners should address these invaders in the autumn to minimize the spring re-emergence with the following measures:

  • Seal entryways: cracks along the doors, window and outlets.
  • Vacuum up: prepare a vacuum with a nylon stocking. To properly eliminate after vacuuming, either freeze the stocking overnight or soak in soapy water.
  • Spray against further infestations.

Consult your custom homebuilder when embarking on your dream home project to optimize your efforts in preventing this Autumn pest from invading your indoor space.