Also called the "multicolored Asian lady beetle", this insect was first reported in NC in 1992. It has never been released in NC, but it moved in from surrounding areas. It has been found on a wide variety of crops (including small grains, corn and cotton), trees (maple, white pine and Fraser fir) and shrubs (roses, crape myrtles, and Eleagnus
). During the spring and summer months, they eat large numbers of aphids, adelgids, insect eggs, and other soft-bodied insects.
In the fall this species aggregates, forming large groups to overwinter. They orient to large objects on the horizon, often barns, churches or houses, sometimes arriving by the hundreds or thousands. This behavior typically coincides with the peak fall foliage colors.
Because the beetles arrive over a period of several days to a week, chemical sprays are ineffective, and multiple applications of these materials may be a health hazard. The best treatment is to prevent entry through use of well-fitting screens and caulk to seal cracks and gaps. Once beetles are inside, vacuum to remove them and deposit outside. Do not leave the bag in the vacuum cleaner; dead decaying beetles will create a bad odor.
Although we consider these insects to be beneficial during most of the year, we recognize that they are a nuisance when they aggregate in buildings. To alleviate this, we are studying the biology and behavior of the beetles when they aggregate, with the goal of developing effective interception traps.