For a few weeks now, I’ve been receiving questions on the subject of ladybugs, also known as lady beetles. The little orange beetles with black spots have long been considered beneficial insects and one that gardeners like to have around. They do eat aphids, which no one wants in the garden or the crop field. During the growing season they are scattered around the landscape, eating other insects that are smaller than they are.
The problem at this time of the year is that many people are getting too much of a good thing. During warm days following cooler weather in the fall, ladybugs tend to cluster in large numbers on the warmer, sunny sides of houses. They are looking for places where they can spend the winter and have protection from the cold and the wintry conditions. Any crack or crevice will provide shelter, and the little buggers can find their way inside houses like magicians. Besides residents not appreciating crawling bugs inside the house, they can further antagonize occupants by leaving stains on walls or carpets.
Although native ladybugs exhibit the same behavior, it’s mostly the Asian ladybugs that are in great enough numbers to be a nuisance. Technically called the multicolored Asian lady beetle, these insects were intentionally introduced into North America to control insect pests of trees, shrubs and crops. In their native Asia, the insects overwinter in cracks in cliff faces. Here they look for overwintering sites where they can find them, often in homes. They will become inactive during the winter, not feeding or mating, just waiting for warmer days.
Control measures include the sealing of all exterior cracks that allow entrance into houses and use of pesticide sprays to repel them. Once inside, a vacuum cleaner can be an efficient tool for removal, using a nylon stocking as a catching device to keep them out of the vacuum bag.
In a few weeks, we’ll have some cold weather, and the ladybugs will no longer be such an obvious nuisance around homes. They are a temporary aggravation each fall that may be with us for the foreseeable future.