Multicolored Asian Lady Beetle

The Multicolored Asian Lady Beetle (MALB), often referred to as a lady bug, is becoming an insect of increased interest this fall as temperatures cool down and many insects begin to make their annual migrations (Figure 1). The MALB survives the winter as an adult and at this time of year begins to search for protected areas such as homes, barns, and other outbuildings. Although they can be viewed as pesky when they enter our homes, these beetles were actually introduced into the United States by the USDA in the 70’s and 80’s to help control aphid populations. Aphids are small insects that can build up in large numbers on many Kansas crops as well as other plants and can cause damage by feeding on plant sap and creating a sugary substance called honeydew that causes plants to develop sooty molds. The MALB is effective at controlling aphid populations and can be found throughout the summer in trees and shrubs feasting on these little pests. So, how do you recognize a multicolored Asian lady beetle? They look like other lady beetles but are larger, about 1/3-inch long. It can be difficult to give a diagnostic characteristic because their appearances can be variable, ranging in color from orange to yellow to red. This beetle typically has 19 black spots which again, can vary in appearance from well-defined to no more than faint traces on its wing covers. They may also have fewer than 19 spots or no spots at all. One of the more reliable identifying characteristics of the MALB is the prominent black 'W' on the thorax behind the head. This 'W' can look thick, thin or even broken in appearance (Figure 2). Now that the weather is changing and food sources are decreasing, the multicolored Asian lady beetles are beginning to search for overwintering sights. They may invade a suitable site by the 1,000’s and thus can be a real nuisance (Figure 3). Since they are predators they do have chewing mouthparts and can bite. This habit of biting is harmless, but again, can be a serious nuisance. These beetles are very beneficial in helping to control aphids and other plant pests and therefore there really are no pesticides labeled for lady beetle control. The best way to avoid 1,000’s of uninvited lady beetles invading your dwelling this fall is to start preparing now by sealing all cracks around windows, doors, etc. and make sure your screens are tight-fitting if window/doors are left open to enjoy the great fall weather. If invasions do occur, and you’ll notice the start when beetles start aggregating on the south and west side of your dwelling during the late afternoon, it is best to sweep them up with a broom or vacuum and remove them a considerable distance – or they may just quickly return.

Jeff Whitworth	Holly Davis
Extension Specalist	Insect Diagnostician
November 2008

Resources Michaud, J.P. 2005. Multicolored Asian Lady Beetle. /doc/misc.-extension-document/harmonia.pdf Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Hahn, Jeffrey. 2004. Multicolored Asian Lady Beetles M1176. http://www.extension.umn.edu/distribution/housingandclothing/M1176.html. University of Minnesota Extension Service.