University of Illinois Extension


Jörg Schmidt-Bailey
Extension Educator, Urban Integrated Pest Management, countryside Extension Center

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Lady Beetles "Housing" in Illinois

In recent years many Illinois residents have experienced a home invader known as named Harmonia axyridis, also known as the Multicolored Asian Lady Beetle or simply "ladybug." This beneficial insect should not be confused with the tree damaging Asian Longhorned Beetle that has been detected in Cook and DuPage counties.

Adult multicolored Asian lady beetles can vary in color and amount of spots, from pale yellow-orange over bright red to almost solid black and from none to up to 19 spots, depending on temperature and food supply during their metamorphosis.

The multicolored Asian lady beetle was introduced multiple times into the United States from Asia to assist in controlling soft-bodied insects such as aphids and some scales. It was fairly successful and has adapted well to living and reproducing in the United States. And by now its growing numbers and further distribution tend to be a nuisance for homeowners because of the beetles wintering habits.

In their native Asian habitat, the beetles congregate in crevices and cracks of cliffs and rock faces and become inactive as soon as temperatures drop; here in Illinois however, cliffs and exposed rock faces are not very abundant and the beetles choose buildings instead. If foundations, siding, and screens are in good repair, then most beetles looking for hiding places in the fall will remain outdoors. And you may encourage them to do so by installing "lady beetle houses"(available in garden stores or easy to build) outdoors. However, if gaps exist around windows, doors, attic or crawl space of a building, many beetles will enter and congregate inside.

Because most rooms in a house are heated to a comfortable level the beetles never become inactive and during this time most homeowners come in contact with lady beetles indoors and the complaints range from unpleasant smell over stained walls to allergic reactions.

A very efficient method to collect and remove the beetles is vacuuming. You may use your common vacuum or a shop vacuum and insert a piece of cheesecloth or nylon-material into the front part of the hose in order to collect and remove the beetles. (please check out the following web site for details:

Another option is to attract the beetles with a light trap. These traps are commercially available, but you may consider building your own.

If you want to keep the trapped beetles in order to release them in spring, you should place them in the already mentioned "lady beetle house" outdoors or keep them in a container containing plenty of ventilation holes and store the container in an unheated and moist place like a garden shed or unheated garage.

The use of insecticides indoors to control wintering lady beetles is not recommended. Insecticide sprays are likely to have little effect on this hard-shelled insect that is not feeding indoors.

Buildings that had large populations of beetles found indoors should be examined, and all broken screens, cracks in the foundation, and gaps in the siding should be fixed to prevent a future influx.

Outdoors, these beneficial beetles should not be harmed. Their feeding on large numbers of aphids, scales, and other harmful insect pests makes up for the nuisance problems they can cause during winter.

February - March 2002: Starting From Seed | Can I Prune Now? | Lady Beetles "Housing" in Illinois| New Septic System Publications | Weird Weather

Past Issues

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