Saturday, September 19, 2009

Landscape - Fall House Invaders 2: The Multicolored Asian Lady Beetle

Asian lady beetles are another problem insect that enters houses in the fall. The following is more information.

The multicolored Asian lady beetle (Harmonia axyridis) [MALB] probably arrived in the US as a result of large-scale aphid biocontrol program releases in the 70's and. It has expanded its range in recent years. These lady beetles are attracted to dwellings that mimic the light stone outcroppings of their native overwintering sites (i.e. white or bright colored houses). MALB feed on a wide variety of pests including hemlock woolly adelgid. However, they have also become a nuisance because they congregate in buildings beginning in fall. Identification of MALB based on color or spot pattern alone is very difficult several different color forms with and without spotting are often present. They will rarely give a small bite.

Different forms of the multicolored Asian lady beetle. Photo from the Pennsylvania Department of Conservation and Natural Resources - Forestry Archive,

Information from Casey Sclar, IPM Coordinator, Longwood Gardens

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