University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Ladybugs Again Returning to Houses

October 4, 2001

Once again, the multicolored Asian lady beetle is very visible around homes and buildings. On a nice sunny fall day, they can be observed flying around yards and parks and converging on walls of buildings, especially on south or west walls. Unfortunately, they often make their way into the building to spend the winter.

Multicolored Asian lady beetles are relatively new to Illinois and the upper midwest. These insects range from 1/4 to 3/8 inch long, and usually have orange wing covers with 19 black spots. However, as the name implies, shades of color can vary and spot numbers range from none to 19. In all cases, the area behind the head has a pair of white oval markings that form a black M-shaped pattern. This can distinguish this species from other lady beetles.

The multicolored Asian lady beetle species migrates to cliffs in its native Asia to overwinter in cracks and crevices. Not finding any cliffs here, the insect goes to buildings instead. This is why they are common in and around homes as cool weather returns with fall.

Lady beetles will not reproduce indoors and do not feed indoors. They are only indoors for shelter to overwinter, and will find their way back outdoors in spring. They will feed on aphids and other insect pests on plants.

Restrict entry into homes by caulking or using weather-stripping to seal cracks and crevices. If needed, remove by hand or vacuuming when found indoors. Spraying insecticides indoors is not suggested.

Multicolored Asian lady beetles may bite, but do not injure humans. If crushed or handled roughly, they may leave a stain on fabrics, carpet, or drapes. In addition, dust produced from the accumulation of dead multicolored Asian lady beetles in wall voids may trigger allergies or asthma in people.

 

Click here for the full article index