Multicolored Asian lady beetle (Harmonia
axyridis)This insect has a wider range of colors and spot numbers
than other lady beetle species. Wings range from black to mustard; spots number
zero to many. The most common U.S. form is mustard to red with 16 or more black
The Multicolored Asian Lady Beetle
Agricultural Research Service, USDA
October 30, 2000
The multicolored Asian lady beetle (Harmonia axyridis) is native to
Asia but occurs in many areas of the United States. This beneficial insect was
imported and released as early as 1916 in attempts to naturally control certain
insect pests. But the first populations were not found in this country until
1988 in Louisiana near the busy port of New Orleans.
Over the years, federal, state and private entomologists released the insect
at a number of locations. But it was not detected in these places until some
years after it had became established in Louisiana. In addition, accidental
entries have occurred via imported nursery items at ports in Delaware and South
Carolina. Thus, it is uncertain whether the beetle's establishment resulted
from planned releases, accidental entries or both.
The multicolored Asian lady beetle is similar to other familiar lady beetles
commonly found throughout the United States. Like the familiar lady beetles,
the multicolored Asian lady beetle feeds on insect pests in orchards and
forests but may also occur on row crops and in gardens.
Lady beetles have four distinct life stages: egg, larva, pupa and adult. The
multicolored Asian lady beetle adults begin laying eggs on host plants in early
spring. Eggs hatch in about three to five days, and larvae begin searching on
plants for aphids and other soft-bodied arthropods on which to feed. Adults and
larvae typically feed upon the same prey. Larvae molt four times, becoming
larger after each molt, and enter an immobile pupal stage after the last molt.
After several days, the adult beetle emerges from the pupal case.
Development time from egg to adult requires about 15-25 days depending on
temperature and food availability. Later in the fall, near the time of killing
frosts, the adult beetles seek shelter to spend the winter.
This variably colored and spotted lady beetle is an effective, natural
control for harmful plant pests such as aphids, scale and other soft-bodied
arthropods. Still, its tendency to overwinter in homes and other buildings,
sometimes in large numbers, may make them a nuisance to many persons.
If agitated or squashed, the beetles may exhibit a defensive reaction known
as reflex bleeding, in which a yellow fluid with an unpleasant odor
is released from leg joints. This reaction generally prevents predators, such a
birds, from eating lady beetles. But in the home, the fluid may stain walls and
Multicolored Asian lady beetles have become a problem in some regions of the
United States. It is probable that their introduction into new habitats in the
United States freed these lady beetles from some natural population checks and
balances that occur within their native Asian range. It is likely that these
natural controls will catch up to the lady beetles in time and curtail their
booming population. Additionally, a period of time may be required for checks
and balances of our native lady beetles to adapt to this newcomer.
Multicolored Asian lady beetles are beneficial insects. Their natural
control of aphids in pecan orchards has decreased insecticide use against those
pests. Additionally, they have controlled aphids on some ornamental plants.
Still, these lady beetles are unwelcome guests for many homeowners.
What These Insects DoAnd Don't Do
Lady beetles are not structure-damaging pests, unlike insects such as
termites and carpenter ants. Lady beetles do not chew or bore holes in walls or
eat carpet or furniture. They do not lay their eggs in homes.
Multicolored Asian lady beetles are attracted to lighter colors: whites,
grays, yellows. So, light-colored houses, especially on hillsides in forested
areas, might serve as homing beacons.
Once the lady beetles enter the walls of a building through cracks and
crevices, they may or may not proceed to the interior of the building. Most
stay in the wall spaces.
During warm days of late winter and early spring, overwintering beetles in a
wall space may become active. In their search for an exit, they may enter the
home's living areas and become a nuisance. Warmer temperatures or lighting in
the living areas may attract these active beetles as they search for an exit.
Prevention and Control
Preventing the lady beetles from entering is the best approach to keeping
them from becoming a household nuisance in fall and winter. Caulking exterior
cracks and crevices--before the lady beetles seek overwintering sites-- is the
best way to keep them out. This will also keep out other unwanted insects such
as wasps, and will save homeowners money on energy costs.
Lady beetles that enter wall spaces in the fall may remain there, without
entering living areas, until they depart in spring to search for food. But some
may become active on warm days in late winter or early spring and move into
Sweeping and vacuuming are effective methods for removing these lady
beetles from living areas. Using insecticides indoors for control of the lady
beetles is not typically recommended unless the infestation is very heavy, and
professional pest control advice should be sought.
Lady beetles that enter living areas are typically attracted to light. A
trap for indoor use that uses light to attract lady beetles and other flying
insects was developed by entomologist Louis Tedders (retired) and colleagues at
the Southeastern Fruit and Tree Nut Research Laboratory, Agricultural Research
Service, Byron, Ga. The insects become trapped in a removable bag. Use of
insecticide is unnecessary. A patent application was filed, but a patent was
Detailed technical instructions and diagrams for constructing
the trap are available on an ARS web site in PDF (portable document format) at:
For more information
You can request additional information and guidance from
your state and local Cooperative Extension agents and scientists. Check your
local directory for the Cooperative Extension telephone number.
On the Internet, you can find Cooperative Extension contacts at state land-grant universities by following the state links at the "State Partners" page of the web site of the USDA National Institute of Food and Agriculture. The "State Partners" page is at
A March 1995 story in
Agricultural Research magazine discusses
Harmonia and several other non-native lady beetle species.
An ARS scientific research contact is Ted E. Cottrell of the
Fruit and Tree Nut Research Laboratory, Byron, Ga.,