Introduction of the MALB, by many measures, was a huge success, because this species has proven to be a helpful biological control against crop pests of pecans, apples, citrus, alfalfa, corn, cotton, tobacco, wheat, and soybeans.
On the other hand, Asian lady beetles are not welcome when they swarm into homes in late summer and fall. Once indoors, they buzz around living room lights at night, emit a unique foul odor when disturbed, and excrete a yellow, staining fluid on walls and fabrics.
Researchers have found that the swarming of this species is especially intense on warm, sunny fall days that occur right after a cool, overcast period. They seem especially attracted to bright, sunlit sides of houses in afternoons, and congregate the most in places with strong contrasts between light and dark-colored surfaces, such as dark shutters on a light house.
To exclude MALBs from a building, use caulk or similar sealant to seal cracks around windows, siding, utility pipes, and other possible entry points. To remove these insects from your home, vacuuming them is probably better than a broom and dustpan, as the latter will cause the insects to secrete their stinky, staining liquid.
Missouri's grape growers have discovered that these beetles take shelter in grape clusters late in the season. Then, when the grapes are harvested, the beetles, crushed along with the fruit, cause "off" flavors in the finished wine. The problem is worst with grapes that are harvested late in the season, including Nortons and grapes intended for late-harvest dessert wines.
Fortunately, Asian lady beetles are not known to be particularly injurious to humans: they do not transmit diseases, nor do they possess venom. They do not destroy clothing, wood, or food. In large numbers, however, for people who are predisposed they can trigger allergy or asthma symptoms. In general, people should avoid touching their eyes or noses after handling these insects.