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Multicolored Asian Lady Beetle

- This lady beetle can be a nuisance sometimes -

Summary: This lady beetle (ladybug) was intentionally brought to the US to help control aphid pests. Ironically, it has been so successful that large populations sometimes develop that become pestiferous.

Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)

What are Asian lady beetles?

The multicolored Asian lady beetle (Harmonia axyridis), is not native to the US. The beetle was intentionally imported a number of years ago to control aphids that feed in trees. This lady beetle has been so successful, however, that populations have increased to the point that in some areas the beetles have become a nuisance pest. So, on the one hand, they serve a beneficial purpose as predators of pest aphids but they are also seen as pests themselves by some homeowners.

The main problem is that lady beetles congregate in large numbers and try to enter houses in the fall in search of a protected place to spend winter months. If they do gain entry they can be a pest all winter. They do no direct harm but some believe they contribute to indoor allergies and they can be messy.

misspellings and misnomers: asian lady bug beetle, ladybugs, ladybeetle

 
Harmonia axyridis; multicolor Asian lady beetle
Harmonia axyridis, the multicolor Asian lady beetle; photo by USDA/ARS; many color forms are possible, see the pdf file below.
 

What to do to with Harmonia

Try to prevent lady beetles from entering homes in the fall by sealing cracks, fixing broken screens, etc. These measures will have the added benefit of sealing out other pests as well as the weather.

If beetles get indoors sweep them up and deposit them outside. Some people even store them in the refrigerator for release into the garden in the spring; give them a little water in a plastic container. In either case don't resort to insecticides. Insecticides won't be very effective and they can cause respiratory problems too.

Remember, as pesky as lady beetles may be indoors, outdoors they really are good for your landscape and garden as natural predators.

Related information: [Harmonia axyridis Guide (pdf)]; Information and pictures of the various color forms of this "multicolored" beetle.

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Identification guides, reference and gardening books, etc.

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Jack DeAngelis, Ph.D.

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