Asian Lady Beetles

Park Service does not release Asian Lady Beetles

The Asian lady beetle is a predatory lady beetle native to eastern Asia. Lady beetles are often used as a biological control agent targeting soft-bodied insects such as aphids and scales. An adult lady beetle is capable of eating 90-270 aphids per day. Lady beetles are now present across much of North America, with reports as far west as Oregon. In their native Asian environment, lady beetles stay in cracks and crevices of cliffs in the winter, but in many areas of the United States, these beetles become a nuisance when they gather in buildings (because of the lack of warm cliffs), often emitting a noxious odor and yellowish fluid when alarmed. The population boom has probably been caused by the massive abundance of prey and a lack of natural enemies. The Asian lady beetle is also known as the Halloween lady beetle and the Japanese lady beetle.

Myths and Misconceptions about the Asian Lady Beetle

The National Park Service has never released Asian lady beetles in or near Great Smoky Mountains National Park. The Park Service has recently released tiny black beetles that prey on hemlock woolly adelgids (which kill hemlock trees), but they are tiny, the size of a pinhead, and do not congregate in homes during winter.

  • Asian lady beetles do not reproduce in structures. Mating occurs after the beetles leave their hibernation site.
  • The beetles do not carry diseases that affect humans.
  • The beetles do not eat wood or building materials.

Why was the Asian Lady Beetle Brought to the United States?

From the 1960s to 1990s, federal, state, and private entomologists released the insect in a number of places to control agricultural pests, especially of pecans and apples. Large numbers were released in Louisiana and Mississippi. In addition, accidental entries of Asian lady beetles have occurred via imported nursery items at ports in Louisiana, Delaware, and South Carolina. Asian lady beetles are also sold by gardening suppliers.

 

Managing Lady Beetles

The best way to prevent being bugged by lady beetles is to prevent them from entering your home. This may require sealing around windows, doors, and other entry points, such as around utility pipes; installing insect netting over attic and exhaust vents, and replacing damaged door and window screens. An exterior home pesticide treatment has also recently become available from commercial pest management companies.

If lady beetles do get into your home, vacuuming is a quick and efficient method of gathering the beetles. After vacuuming, simply remove the beetles from the vacuum, place them in a bag, seal or tie the bag shut, and dispose.

There are commercially made traps and pesticides available, however bug "bombs" or aerosol foggers are not recommended to control lady beetles because they do not affect the majority of the beetles that are hidden inside walls. Dead beetles left by interior pesticides may also invite invasions of more destructive insects later on.

How to Identify the Asian Lady Beetle

The Asian lady beetle appears in many colors from pale yellow-orange to bright red-orange. The adults have a mostly oval body shape about 1/4" long. The Asian lady beetle is identified by the telltale "M" or "W" shaped mark on the whitish area behind the head. All Asian lady beetles have this mark; lady beetles native to the United States do not. The number of spots on the wings tends to vary from beetle to beetle.

For More Information Please Visit:
http://www.ars.usda.gov/is/br/lbeetle/

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