Asian Lady Beetles in Wisconsin
Commonly mistaken for the ladybug, the multicolored Asian lady beetle was introduced into the United States from Asia to control aphids, scale, and other crop pests from 1978 to 1981. It is now widely distributed from Mississippi to the Midwest, Southwest, and Pacific Northwest. Asian lady beetles may enter homes in large numbers and have become consistent overwintering pests in buildings and homes.
Asian Lady Beetle Habitat
This species is a voracious predator of crop pests and produces several generations per year. Their tendency to aggregate and ability to enter structures often causes this insect to become a significant structural pest. Hundreds and even thousands of these beetles have been found in and on homes. Asian lady beetles can be found in attics, wall voids, on siding, inside closets, and may be attracted to light.
Asian Lady Beetle Behaviors, Threats, or Dangers
Although Asian lady beetles may bite, their bite does not seriously injure humans or spread diseases. If handled or crushed, they will emit a foul odor and leave a stain. In fall, beetles seek out crevices and protected areas around homes to spend the winter, congregating in attics, wall cavities, cracks around door frames, and within soffits and wall voids. If a large number of beetles gain access inside of homes, they can stain drapery and clothing. Asian lady beetles cannot survive sub-freezing temperatures, although they can survive within homes and buildings that provide adequate warmth and humidity. If you are dealing with an infestation, always contact a licensed beetle exterminator.
Asian Lady Beetle Prevention & Control
Asian Lady Beetle Prevention
The best course of action to stop Asian lady beetles from entering the home is to take preventative measures. This includes, but is not limited to:
- Sealing off all entry points to the building outdoors, including where phone lines, cable TV wires, and other pipes and vents enter buildings
- Caulking openings in the foundation and around plumbing, electrical conduits, and windows
- Repairing or replacing any damaged window or door screens, screens in roof vents and in bathroom and kitchen fans
- Covering vents
Asian Lady Beetle Control
DIY Control
- Don’t crush them! Avoid stepping on or squashing Asian lady beetles, as the insect may stain carpets, other fabrics, or walls.
- Vacuum! Simply vacuuming the insect up may prove effective.
- Prevention is the key, so caulk and close up window and door frame gaps, and any other openings into the building.
Professional Pest Control
To prevent Asian lady beetle entry, an insecticide treatment must be applied during late September or early October before the insects begin to enter buildings, in order to be effective. Once the pests have entered the building, an interior treatment can be done in winter or spring that will eliminate them as they come out of hibernation.
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