Asian Ladybugs: Friend or Foe?

— Written By Susan Condlin and last updated by

Ladybugs are familiar insects in and around the home garden. Larva and adults consume hordes of aphids, scales, and other soft-bodied insects, providing chemical-free control! As weather becomes cooler, ladybugs start looking for a warm place to spend the winter and sometimes become a nuisance indoors.

First off, the ladybug is actually a lady beetle. According to entomologists, the ladybug is not a true bug; instead, it belongs to the beetle family. Bug or beetle, I think you know the insect I am referring to.

The ladybug that is infamous for invading home is the multicolored Asian ladybug. This insect is not native to the United States (although we do have native ladybug species in the States). The USDA, as an attempt to naturally control soft-bodied insects, released the Asian ladybug.

The multicolored Asian ladybug is variable in appearance. Most beetles are about ¼ inch long with yellowish, orange, beige, or reddish orange forewings. There are usually ten black spots on each forewing; however, the number of spots is variable too.

Now that fall has set in, these ladybugs start looking for a protected place to spend the winter. Suitable locations often include the sunnier or warmer sides of buildings and light-colored buildings, although many other buildings may pass as suitable. Research suggests that the beetles use chemical cues to find the crevice and may explain why the insects may return to the same site repeatedly.

Ladybugs can fit through tiny gaps or cracks in the siding or around door and window casings. Through these cracks, the beetles can get into your home. Many times, the adults will pass the winter in wall voids. Once inside a heated home, the ladybug will not live very long.

These beetles will not damage the structure of your home nor will they chew holes in walls or fabric. Primarily the Asian ladybug is a nuisance; however they may release a smelly, yellow liquid if agitated or smashed. This liquid can stain fabric and painted surfaces.

Pesticides are not very useful in fighting a ladybug invasion. Repeatedly spraying pesticides indoors is not safe for humans or pets and may not control the problem.

Exclusion is the best long-term approach to controlling ladybugs in the home. Make sure there are no gaps around the door. Install weatherstripping and seal utility openings. Caulk around windows and doors.

Inside the home, vacuuming can be an effective way to clean up the mess of insects. Insert a women’s knee-high stocking into the extension hose and secure with a rubber band. The stocking will collect the beetles and provide for easy disposal. If you do not use a stocking, you will need to empty the bag soon after vacuuming because the bag will begin to smell.

Once you have vacuumed the beetles, you can choose to release the live beetles outside (they may find their way back in your house), freeze the beetles to kill them, or keep them in the refrigerator to release in the spring (many will die in the refrigerator).

Ladybugs are a beneficial insect when they are feeding on insects outside. Sometimes, they will find a way indoors and become a nuisance. For the best long-term control, examine your house for cracks or entryways and seal them. For more information on ladybugs, reference ENT/ort-107: Multicolored Asian Lady Beetle Inside Homes or contact our Center at 775-5624.

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