Lady beetles making house calls

Garrard Coffey
Agriculture and Natural Resources

Lady beetles are widely recognized as beneficial insects. In the fall, they congregate to spend the cold winter months in sheltered sites: rock piles, tree holes, etc. However, the multicolored Asian lady beetle has a nuisance side. It is attracted to prominent terrain features, such as a vertical rocky outcropping.

Following this visual cue leads many beetles to homes and buildings. After landing, the normally helpful insects crawl around searching for cracks or crevices to enter before settling for several months of inactivity. Some enter via gaps around windows, doors, and through ventilation openings. They will stay there during the winter and will remain active in the warm surroundings.

Adult Asian lady beetles are oval, convex and about 1/4 inch long. Their color can vary widely from tan to orange to red. Most have several black spots on the wing covers, although the spots may be indistinct or entirely absent on some beetles. Most beetles have a small, dark M- or W-shaped marking on the whitish area behind the head.

Lady Beetle Management

Vacuuming – Once the beetles are indoors, the easiest way to remove them is with a vacuum cleaner. A broom can also be used, but is more likely to result in staining when beetles emit their yellowish defensive secretion.

Sealing entry Points – Sealing cracks and openings is the most permanent way of preventing lady beetles from entering buildings.

Insecticides-Indoor Treatment – Insecticide foggers, “bug bombs” or sprays are generally not recommended for eliminating beetles indoors. A better approach is to take preventive measures to reduce beetle entry in subsequent years.

Insecticides-Exterior Barrier Treatment – While sealing cracks and openings is a more permanent way to limit beetle entry, the approach is time-consuming and sometimes impractical. If lady beetles are a perennial problem, many owners may want to hire a professional pest control firm.

Many companies apply insecticides to building exteriors in the fall which helps prevent pest entry. To be effective, barrier treatments should be applied before the beetles enter buildings to overwinter.

The University of Kentucky Extension publication, “Asian Lady Beetle Infestation of Structures” (ENTFACT 416) offers more information and management recommendations; and the University of Kentucky Extension publication, “How to Pest-Proof Your Home” (ENTFACT 641) can provide additional tips. For a copy of each publication, contact the Whitley County Cooperative Extension Service at 549-1430; visit the office currently located in Cumberland Regional Mall, 965 S. Highway 25W, Williamsburg; or email DL_CES_WHITLEY@EMAIL.UKY.EDU.

Source: Information, in part, printed from University of Kentucky College of Agriculture, Food and Environment publication, Kentucky Pest News, October 28, 2014, and the University of Kentucky of Kentucky Extension publication, “Asian Lady Beetle Infestation of Structures” (ENTFACT-416).