Prevent Lady Beetle Invasions to Your Home

Fall brings wonderful colors, the smell of harvest in the air, and the not so great annual invasion of multi-colored lady beetles. Generally in late-September through October the Multi-Colored Asian Lady Beetle begins to seek out shelter where they will spend the winter hibernating. They prefer cavities that stay cool dry and offer concealment. In there native range of Asia the adult beetle seeks out cavities in cliff faces. In Ohio, the multi-colored Asian Lady Beetle adults seeks overwintering sites oriented toward light colored conspicuous objects such as light colored buildings especially on south and southwest sides of walls warmed by the sun.

Before we condemn this beetle as a complete nuisance, keep in mind that the Asian Lady Beetle is an important predator that consumes large numbers of aphids and scale insects on trees, shrubs and agriculture crops through out the spring and summer months. However, their choice of an overwintering location (generally people’s homes) leaves much to be desired. People often express concern and aggravation with these nuisance insects. The beetle will periodically invade living spaces in response to the warm interior temperatures. On warm sunny days they may move about and fly within the home.

When Asian lady beetles are disturbed they defend themselves by exuding a yellow-orange fluid. This fluid has a foul odor and can permanently stain walls, drapes, carpet and clothing. Refrain from crushing or swatting to minimize the release of this fluid. Asian Lady Beetles can bite but generally are not aggressive. Theses “nips” or “pinches” do not usually break the skin. They do not carry disease nor do they have any toxin associated with their mouthparts.

The best management recommendation is to prevent the beetles for entering the home or building. Outdoors check for and seal all obvious cracks and spaces where beetles can gain access. Check attic screens for holes, caulk wherever a utility pipe, telephone or cable enters the siding and make sure the weather seal on doors and windows is tight.

Chemical treatments can provide protection to help prevent pest entry. The pesticide typically is applied to outside walls and siding, as well as around eaves, attic vents, roof overhangs, and doors and windows. Pre-test a small area to ensure that the chemical treatment does not cause staining or discoloration. If using a pesticide, Ohio State University Extension researchers recommend using a pyrethroid insecticide product. Examples of pyrethroid active ingredients include: bifenthrin, cyfluthrin, cypermethrin, deltamethrin, etc.

Inside the home the use of a vacuum is the best defense. In small numbers, you may find the use or sticky tape helpful with capturing the flying beetle. Vacuuming is the most efficient and rapid technique. Be sure to empty the sweeper bag or receptacle immediately as the odor from the beetle can be quite unpleasant. Ohio State University’s official FactSheet on Multi-Colored Asian Lady Beetles is available at http://ohioline.osu.edu/hse-fact/1030.html