The Asian lady beetle, Harmonia axyridis (Pallas), is common in many parts of the United States. It is also common in Europe and the U.K. This beetle was imported from Asia to control aphids and other plant-feeding insects.
There are more than 400 native species of lady beetles in North America. Only a few species are considered pests. Because there are so many variations in coloration, many people refer to all of these beetle species as “ladybugs”.
The Asian lady beetle is slightly larger than many of the native lady beetle species in North America. It can be as large as 3/8″. It is usually reddish-orange. There may be black spots, but they are sometimes missing. The Asian lady beetle is found in most of the United States and parts of Canada.
Because the lady beetles are predators of plant pests, they are considered to be beneficial insects. They often make nuisances of themselves. In late summer and autumn, the adult beetles gather on the sunny side of homes to keep warm. They often find cracks that allow them to enter the walls or attic. Many of the beetles spend the winter hibernating in dark areas of the home.
During the winter, whenever there is a sunny day, the walls become warm and the beetles become active. Many of the beetles find openings that allow them to get into the interior of the home. When they emerge into the living space, the beetles fly toward the windows and doors. They gather on the windows and the nearby walls trying to get outside.
The clusters of beetles –outside in the fall and inside during the winter – can be extremely frustrating to the homeowners. Some pest control professionals report that the largest volume of calls they receive is for lady beetles.
Because lady beetles are beneficial, many people prefer not to kill them. In fact, there are very few insecticides that include lady beetles on the label. It is usually possible, and fairly easy, to manage lady beetles — even without insecticide.
Swatting lady beetles can be messy – they can leave a stain if they are crushed.
It is often easiest and quickest to use a vacuum cleaner to remove any lady beetles that make their way inside the home. Some vacuum cleaners are made so that the beetles can be released outdoors.
During the summer, an outdoor inspection can help prevent many future lady beetle problems. Caulk any cracks around doors and windows. Make sure exterior doors close tightly and replace missing weather-stripping. Repair damaged screens on windows and vents – check the attic vents too.
An insecticide that includes the words “Perimeter Application” on the label can be used for a barrier on the outside. This will repel many species of insects that try to spend the winter on or in the home. Because of the effects of sunshine and rain, the insecticide barrier will have to be reapplied periodically. Many people find it more convenient to have a pest control professional make these applications for them.