Do Asian lady beetles live in groups?
Asian lady beetles behave in an unusual way: when autumn arrives, they cluster by the thousands on the outside walls of houses, looking for a way inside. In the spring, they do the reverse.
Asian lady beetle: How to prevent an invasion
Published on July 31, 2026
3 mins reading time
In the fall, thousands of Asian lady beetles may seek refuge in homes to spend the winter. Learn how to recognize them, limit their entry and get rid of them effectively if they invade your home.
How to recognize the Asian lady beetle
The Asian lady beetle (Harmonia axyridis) is best identified by the “M”-shaped marking behind its head and the two white spots near it. Its colour ranges from yellow to black, including orange and red, with anywhere from zero to nearly twenty black spots. It is generally larger than its native cousins found in Quebec.
Introduced to the United States in the 1980s to control aphids, the Asian lady beetle later spread to Canada. Today, it can be found in many regions of Quebec.
Asian lady beetle: Helpful or harmful?
Helpful
- The Asian lady beetle helps control certain harmful insects, particularly aphids that attack plants.
- It’s also part of the food chain for many animals.
- It doesn’t sting, transmit disease or contaminate food.
Harmful
- It can enter homes in large numbers to spend the winter in the warmth.
- When disturbed or crushed, it releases a foul-smelling orange liquid that can leave yellow stains on certain surfaces.
- It may contribute to the decline of certain native species¹ by outcompeting them.
Good to know: In winemaking, the accidental presence of Asian lady beetles in grapes can sometimes affect wine quality.
Why do Asian lady beetles enter homes in the fall?
As winter approaches, Asian lady beetles gather by the thousands on the sun-exposed sides of homes in search of a warm place to shelter. They can then make their way in through cracks, windows and other exterior openings. In the spring, they repeat the same behaviour indoors as they try to get back outside to resume their reproductive cycle.
How to prevent a lady beetle invasion in the fall
The best way to limit their presence and protect your home is to seal entry points before they arrive in the fall.
- Caulk holes, cracks and crevices on the sides of your home most exposed to the sun.
- Keep door and window screens in good condition.
- Fit exterior ducts and vents with appropriate covers or screens.
- Check that door frames are properly sealed.
How to get rid of Asian lady beetles in your home
A vacuum is the simplest way to catch Asian lady beetles indoors. Afterward, empty the vacuum or dispose of the bag right away to prevent them from getting back out.
Some strong scents, such as peppermint, citronella, camphor, garlic or cayenne pepper, are sometimes used to repel them. However, their effectiveness varies and the effect is often temporary.
Using pesticides outdoors isn’t recommended. As the beetles decompose, their remains can attract other insects looking for food sources.
When to call a pest control specialist
If Asian lady beetles become a significant problem despite your prevention efforts, a pest control specialist can help you find a solution suited to your situation.
Good to know: CAA-Quebec’s Residential Advisory Services can guide you and recommend a reliable company.
FAQ – Asian lady beetle
It’s generally not toxic to pets, but ingesting a large amount can cause digestive irritation. Consult a veterinarian if your pet shows unusual symptoms. CAA-Quebec Home Insurance policyholders can speak with a technician or veterinarian free of charge through The Assistant for pet health.
It’s a defence mechanism against predators. When it feels threatened, it releases a foul-smelling yellowish or orange liquid.
No. The Asian lady beetle doesn’t sting and generally isn’t dangerous to humans. However, it may give a slight bite when handled.
To learn more about the Asian lady beetle
ESPACE POUR LA VIE MONTRÉAL
Asian lady beetle
PEST CONTROL TIPS
How to tell apart the main lady beetle species found in Quebec (In French only)
1. For this reason, the Asian lady beetle appears on the list of exotic species of concern (or potential concern) present in Quebec, compiled by Quebec’s Ministry of Forests, Wildlife and Parks.
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