Ladybugs are generally regarded as one of the beneficial insects that should be encouraged to inhabit our gardens. They are one of the best controllers of aphids or greenfly that attack our plants. So why is there a “but” and what is not to like about these colorful spotted insects? According to Master Gardener Kristie Auman-Bauer there can be problems with an Asian variety of ladybug as she explains in her article I found on The Master Gardeners website.
Lady beetles are known to be beneficial insects and, some say, good luck. But many people panic at the sight of the small, reddish colored beetles covering the outside of their homes each fall, especially when they start making their way inside.
There’s no need to be alarmed about these nuisance pests, say specialists from the Pennsylvania IPM Program. The beetles, called multicolored Asian lady beetles, are native of eastern Asia and came to North America two ways: by accident on imported freight from Asia; and introduced on purpose by the U.S. Department of Agriculture years ago as a biological control agent for crop pests such as aphids and scale insects. These insects are tremendously beneficial in gardens and farm fields during the summer months. They are slightly larger than native lady beetles, measuring 0.2 to 0.3 inches long. They vary in color from yellow to red and may (or may not) have black spots on their wing covers.
The beetles become nuisance pests in early October during sunny, warm afternoons after a cold snap. Lyn Garling, education specialist for the PA IPM Program explains that the cold snap tells the beetles they had better get busy and find a good place to hide for the winter. “Like all insects, they need warmth to move, so they gather on the south sides of houses, sheds and other buildings looking for warmth. Once they get warm, they are on the go. If there are openings into your home, it’s not uncommon for hundreds or even thousands of beetles to make their way onto walls, ceilings and attics. Their tendency is to go up into the attic and ball up to wait out the winter. However, they might get stuck in the kitchen and drive you crazy crawling on windows or falling in your soup.”
See more at The Master Gardeners