ASIAN LADY BUG INFESTATION INFORMATION & FACTS

The multicolored Asian lady beetle (Harmonia axyridis), has become common throughout Ontario. It is well known for the annoying habit of accumulating on the sides of buildings and wandering indoors during the fall. Asian lady beetles are a beneficial biological control in trees during the summer, and in fields and gardens during the fall, but can be a severe household nuisance pest during late fall, winter and spring. Country areas, wooded residential and industrial areas are especially prone to severe problems. These little pests can spread over time and may be more difficult to rid as time passes.

These species of beetles are typically 1/3 inch in length and dome shaped. Their colouring is yellowish-orange to red with variable black spots on the back. Deep orange is the most common color. The 19 black spots may be faint or missing. There is a black shaped mark on the thorax.

Asian lady beetles, like other occasional invaders, are “outdoor” insects that create a nuisance by wandering indoors during a limited portion of their life cycle. They do not feed or reproduce indoors; they cannot attack the house structure, furniture, or fabrics. They cannot sting or carry diseases. Lady beetles do not feed on people though they infrequently pinch exposed skin. Lady beetles may leave a slimy smear and they have a distinct odor when squashed.

Asian lady beetles follow their instinctive behavior and fly to sunny, exposed surfaces when preparing to hibernate through the winter. The time of beetle flight varies but is usually from mid-September through October (depending on weather). Light colored buildings and walls in full sun appear to attract the most beetles.

Learn more about how to get rid of Asian lady beetles.