Multicolored Asian Lady Beetle in Virginia
Multicolored Asian Lady Beetle (MALB) belongs to the group of beetles often called ladybugs, ladybird beetles, or lady beetles. Like other lady beetles, adult MALB are somewhat oval in shape with a strongly convex dorsal surface and a flattened ventral side. The head and thorax of adult MALB are black with light-colored markings. The wing covers range in color from light orange to a dark red or even black (Fig. 1). Multiple black spots are usually visible, but are sometimes lacking; dark colored individuals may have yellow or orange spots.
MALB larvae, like the larvae of other lady beetles, are often described as being “alligator-like” (Fig. 2). They are elongated with orange markings on a dark body and numerous spines or tubercules on the dorsal side. They actively move about on vegetation searching for prey.
Outdoors, both adults and larvae are beneficial predators of soft-bodied insect pests such as aphids, caterpillars, scales, and insect eggs. Adult MALB are considered pests when they enter houses and other building in the fall while seeking protected places to overwinter.
Coleoptera: Coccinellidae, Harmonia axyridis (Pallas)
Control of MALB in Houses
Adult MALB enter houses through small openings around windows, doors, and utility access points. In addition, they can enter houses through cracks in the siding and trim and through attic vents. Sealing those entry sites is the best method to keep MALB out of a house. Conduct a thorough energy audit of your house because any places where cold air can enter the house are also places where MALB can gain access. Fill all cracks and leaks with a fine quality silicone or silicone-latex caulk. Once inside, insecticides are not recommended against MALB except for severe cases. Sweep the beetles up with a broom and dustpan, including all beetles that collect in windowsills and on walls. Beetles can also be picked up with a vacuum cleaner, but bags will need to be discarded so that beetles do not escape back into the living areas.
Do not use a flyswatter or otherwise crush the beetles as they can leave an unsightly orange stain on carpets, drapes, and walls.
MALB Control Check List
- Seal windows and doors with weather stripping
- Check attic and basement for possible entry sites
- Check utility and pipe access points to the house
- Check window screens
- Seal cracks and crevices created by house siding
- Use a vacuum cleaner to pick up beetles
- If spraying for beetles inside, remove deadbeetles with a vacuum cleaner
- Seal between logs if residence is a log home
Beetles typically start entering houses and have an obvious peak of activity around October 15th in Virginia. They are quite active on warm days in the fall and winter. Usually they cluster in wall voids or crawlspaces indoors, but do not reproduce or establish inside the house. They have a second peak of activity in late March as they work their way into the living quarters of the house in an attempt to find their way outside. The heated portions of the house are simply too warm and dry and they die in a few days.
History in Virginia
Despite persistent rumors to the contrary, Virginia Tech did not release MALB in Virginia. MALB was first detected in Lee County, Virginia, in January 1993. By fall of 1993 approximately 40 counties, covering all geographical regions of the state, had new county records. By the late 1990s it was not only statewide in distribution, but also covered much of the United States as well.
History in the US
MALB was first recorded as a pest in houses in 1988 in Abita Springs, Louisiana. Prior to that time, the USDA released MALB many times between 1916 and 1985 as a potential biological control agent against aphids and scale insects. In those trials the beetle was not recovered after the release, so it was assumed that it had not established and was incompatible with North American conditions. The source of the original infestation in Abita Springs, Louisiana, is unknown. The original infestation site in Louisiana is close to ports used for international shipping, including cargo containers from Asia. MALB may have established from intentional release as a biological control agent, or from beetles that hitchhiked from Asia.
Theresa A. Dellinger, February 13, 2020.
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March 17, 2020