Ladybugs In Homes

- The multicolored Asian lady beetle in homes -

Summary: The multicolor Asian lady beetle (ladybug) was intentionally imported into the US to help control aphid pests. Ironically, it has been so successful that large populations sometimes develop and become nuisance pests that invade homes.

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

The problem with ladybugs

Ladybugs, or lady beetles, are normally beneficial insects in that all active stages are predators of garden pests like aphids and spider mites. In other words, we want lady beetles in our gardens. The problem happens when adult beetles try to enter our homes in the fall with the purpose of sheltering there until spring.

Most lady beetles literally "head for the hills" in the fall and shelter in natural cavities. A new imported species, the multicolor Asian lady beetle, likes to spend winters at lower elevations and our houses happen to be very handy. If they gain entry they can be a nuisance pest all winter. They do no direct harm but some believe they contribute to indoor allergies and their droppings can be very messy.

misspellings: Asian lady bug beetle, ladybugs, ladybeetle

Harmonia axyridis; multicolor Asian lady beetle

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

What are Asian lady beetles?

The multicolor 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.

What to do to about Harmonia

Try to prevent lady beetles from entering homes in the fall by sealing cracks, fixing broken screens, and so forth. 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 health 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 Articles

Harmonia axyridis Guide Information and pictures of the various color forms of this "multicolored" beetle.

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