Lady Beetles
Harmonia axyridis
NuisanceWhat it is
Predatory beetles, many of which are beneficial because they feed on aphids and other plant pests. Some species, especially multicolored Asian lady beetles, enter buildings in large numbers to overwinter.
How to recognize it
- Orange to red, about 1/4 inch long
- Anywhere from no spots to many
- A white "M" or "W" shape just behind the head
- Cluster on sunny, light-colored walls in fall
- Release a smelly yellow fluid when disturbed
Where you will find it
Sunny sides of buildings in fall, then attics, wall voids, and around windows. Outdoors they eat garden pests like aphids.
Found across much of the US.
Why it matters
Asian lady beetles gather indoors in large numbers, stain surfaces, and can bite.
Look-alikes
- Native ladybug: Usually bright red with black spots, and no white "M" marking. Rarely gathers indoors.
- Carpet beetle: Smaller and mottled, and it damages fabrics instead of gathering on walls.
What to do
- Vacuum them up and empty the vacuum right away. Don't crush them.
- Skip indoor sprays.
- Contact a professional in early fall, before they move in.
When to call a professional
- You get heavy numbers every fall.
- You want exterior treatment timed for early fall.
Questions
Do they bite?
They can nip, but it isn't harmful.
Why do they stain?
They release a yellow fluid when disturbed, which can mark walls and fabrics.
Are they bad for allergies?
For some people they can trigger allergy symptoms.
Related reading
- Beetles Swarming Your House in Fall? Asian Lady Beetles Explained
- Stink Bugs in the House: Why They Come In and What to Do
Related pests
Occasional Invaders
A broad category for pests that enter buildings incidentally but usually do not reproduce indoors. Examples can include boxelder bugs, lady beetles, millipedes, ground beetles, and other seasonal invaders.
Read more →Stink Bugs
Shield-shaped true bugs that release a strong odor when disturbed. Some species damage crops, while others enter buildings in fall to overwinter and become nuisance invaders.
Read more →Boxelder Bugs
Black-and-red true bugs associated with boxelder and some maple trees. They often gather on sunny exterior walls and enter buildings in large numbers to overwinter.
Read more →Clover Mites
Tiny reddish mites that feed on grasses and ornamental plants. They often invade buildings in large numbers around windows and foundations but do not bite people or damage household items.
Read more →This page is general information, not a diagnosis. Pests vary by region and situation, and an on-site inspection is the reliable way to know what you have.