April 30, 2004 at 10:17 a.m.
They have been around all winter and I imagine their presence will continue. The only good news is during the summer they would rather be outdoors than indoors.
Contrary to popular belief, they do not breed and reproduce inside buildings. Every lady beetle you see this year entered your home last fall. Warm temperatures break their inactive phase. They may try to get outside but many of them end up trapped indoors. If they can’t get back outside, they eventually die.
Originally, these lady beetles were brought into California from Asia in 1916 and in 1964 for control of pecan aphids. They were also released for biological control programs from 1978-1982 mostly in the eastern U.S. It appears that these releases did not become established. In 1988, a population of multicolored Asian lady beetles was found in Louisiana from which they spread throughout the southern and eastern United States. Genetic studies have shown that the lady beetles throughout the county came from a single source but no one knows whether that is from one of the biocontrol program releases or an accidental introduction, such as a freighter.
They were first sighted in Minnesota in November 1994. The first report of major infestation around buildings occurred in 1998, and by 2000 the insect was generally spreading throughout the state. It would be easy to blame some state agency for the beetle. The fact is multicolored Asian beetles were never introduced into Minnesota through releases. As they spread throughout the country, they reached Minnesota from neighboring states.
When I first wrote about them I said they were just a nuisance bug that smells when you destroy them. I have since realized that they can bite and are capable of breaking the skin, resulting in a short-lived pain. Fortunately, multicolored Asian lady beetles are not known to transmit diseases. They are capable of boring into fruits and vegetables like raspberries, strawberries, apples, tomatoes, etc.
During the time I wrote this article four lady beetles landed on me. Every night we vacuum beetles from the window sill in our bedroom. Once they get into the home, your options are limited. Insecticides have very little impact on overall lady beetle numbers. Your only option seems to be to vacuum them as often as you see them.
An economical method to vacuum lady beetles (if you don’t have a dust cup you can dump outside) is to use a knee high nylon stocking that has been inserted into the extension hose and secured with a rubber band. As soon as the vacuum is turned off, remove the stocking so the captured beetles can’t escape. As you remove it, the rubber band closes around the stocking, bagging the beetles. You can then throw away the stocking or discard the contents of the stocking and reuse it.
If you feel that you must use insecticides, do so outdoors. Apply the insecticide to doors, windows, and roof lines, paying particular attention to the south and west sides where the insects are most common. Common examples of effective insecticides available to the public are those containing: bifenthrin, cyfluthrin, cypermethrin, deltamethrin, or permethrin.