printer friendly page

Multi-Colored Asian Lady Beetles (Harmonia axyridis)

During Indian Summer, right after the first frost (and again in February and March), homes Multi-Colored Asian Lady Beetle.  Photo by Bet Zimmermanmay be invaded by hundreds or thousands of Multi-Colored Asian Lady Beetles. These beetles, also called the Halloween Beetle(because of their pumpkin color and timing) or Japanese or Asian Lady Beetle/Ladybug, can be pale yellow, brown, bright orange red, black or mustard in color; with zero to 20 spots, depending on what they've been eating (red for aphids, yellow for pollen), and temperatures during pupation.They were introduced by the U.S. Dept. of Agriculture in 1979-1980 (first recorded in CT in 1994) as a biological control. They will dine on more than 50 species of agricultural/landscape pests such as aphids, scales, and psyllids, including the red pine scale, balsam twig aphid, and pine bark adelgid. An adult, which can live 2-3 years, is capable of consuming 90 to 270 aphids a day.Unfortunately, because of their habit of swarming homes while looking for a place to overwinter, they can become a nuisance. They crawl inside through cracks and crevices and often cluster in corners by window or door frames. While uncommon, some people have reported being nibbled on, or experiencing an allergic reaction to the beetles. Fortunately, they will not reproduce indoors, nor will they eat wood, building materials, or human food.

Do not use any type of aerosol fogger or "bug bomb" in an attempt to control lady beetles. The active ingredient has very limited effectiveness against lady beetles, and humans are unnecessarily exposed to chemicals in indoor environments. Also (ugh), such treatments can cause additional, persistent indoor pest problems because scavenging pests (i.e., ants, carpet beetles and larder beetles, etc.) are attracted to feed on accumulated dead insects. The best techniques for managing lady beetles are the following methods:

Before autumn arrives, seal cracks and openings around windows, doors, siding, and utility pipes with a quality silicone or silicone-latex caulk or weather stripping. Larger gaps can be sealed with urethane foam, glass wool or stainless steel wool, etc.

Keep them outside

  • Install tight-fitting door sweeps or thresholds at all exterior entry doors. Around garage doors, install a rubber seal rather than vinyl, which seals poorly in cold weather.
  • Install insect screening (20-mesh maximum) over attic and exhaust vents.
  • Replace and repair damaged door and window screens using regular window screening (about 18x16 mesh size).
  • They appear to be attracted to light (white, gray, yellow) colors on the sunny side of the house, so if you're really desperate, repaint the house a dark exterior color.

Collect them indoors

  • Gently collect beetles using a broom and dustpan and release outdoors.  Duct or sticky tape can also be used to collect them, but obviously they can not then be released.
  • Use a vacuum cleaner or shop-vac to "bag" the beetles inside a knee-high nylon stocking that has been inserted into the extension hose or wand and secured with a rubber band (see drawing). As soon as the vacuum cleaner is turned off, remove the stocking so that the captured beetles can't escape. As you remove it, the rubber band closes around the stocking, "bagging" the lady beetles. Then discard the contents of the stocking.
  • Don't crush or swat them--the beetles may discharge a stinky yellow fluid that can stain walls, paint, and fabrics. (All lady beetles do this reflex bleeding from their leg joints when alarmed - it's a protective mechanism to prevent consumption by birds. Even Renfield the Cat won't touch them!)

Repel or trap them

  • Camphor may repel them short term. Put camphor cakes or crystallized camphor in a knee-hi nylon stocking. Knot the stocking and hang it on the outside of the house near known entry points, or put cotton balls containing a few drops of camphor essential oil in the corner of the windows. Re-apply oil often. Camphor cakes can be found on the web at http://www.kilianhardware.com. Camphor crystals can be obtained from Stony Mountain Botanicals, 155 N. Water St., Loundenville, OH, 888-994-4857, http://www.wildroots.com.
  • Make or buy a special trap. Traps should be placed in the room that is most infested, and operated in a dark room/at night, and placed in the room that is most infested.  Leave the light on all night. Put cornstarch, talc or baby powder on the wings/sides of the trap so the beetles drop easily into the collection container, and empty the container often.

More Information and References:

Conservation Commission
Ladybug! Ladybug! Fly away home. Your house is on fire. All your children are gone. All except one, and that's little Ann, for she crept under the frying pan.

- Children's nursery rhyme, author unknown