What Causes Ladybug Infestations?

Problems with ladybug beetles occur in the late summer or early fall when the beetles seek out our homes and commercial buildings as a place to overwinter. They invade again in the spring when the warmer weather outside tricks them into thinking it is time to once again get outdoors and resume their lives.

Homeowners often ask their pest management professional why ladybugs seem to be attracted to their house year after year. Ladybugs that find a good overwintering site will produce an attractant pheromone. This chemical attractant stimulates ladybug beetles to return to that site year after year. In addition, ladybugs will be attracted more to buildings that receive afternoon sun exposure on the south and southwest side, plus they seem to be more attracted to structures that have contrasting light and dark colors in the color scheme.

Homes and buildings located close to woods and fields also tend to be more heavily infested by ladybug beetles. The kind of construction materials (brick, wood, vinyl, aluminum) is not an important factor in attracting these insects.

Signs of an infestation

The most obvious sign of an infestation is the appearance of large numbers of ladybug beetles on the outside surfaces of structures, congregated in the cracks and gaps of the siding and inside the building on the walls and ceilings. In addition, the beetles may produce a yellow-colored secretion that is deposited on surfaces.