The multicolored Asian
lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)
was first
introduced
in California by USDA agricultural research scientists as a
biological control agent.
This introduction was deemed unsuccessful.
However, it was reintroduced in the eastern United states in
the late 1970’s and early 1980’s to control soft-bodied insects like
the pecan aphid and pear psylla.
Since its introduction it has spread throughout most of North
America.
introduced
in California by USDA agricultural research scientists as a
biological control agent.
This introduction was deemed unsuccessful.
However, it was reintroduced in the eastern United states in
the late 1970’s and early 1980’s to control soft-bodied insects like
the pecan aphid and pear psylla.
Since its introduction it has spread throughout most of North
America. Adult beetles are domed, round to oval in shape typical of other lady beetles. The name “multicolored” refers to the many color forms of the adult lady beetles. Coloration variants are shades of yellow, orange, and red; with or without black spots on the wing covers.
This species can be recognized and distinguished from other lady beetles by the following
characteristics.
On the white pronotum (the middle body segment between
the head and abdomen) there are several black markings,
which tend to fuse into a regular to irregularly shaped
“M” or “W” depending on your vantage point.
Life
cycle:
The life cycle from egg to adult requires about a
month or so, depending on the weather.
Eggs hatch in 3 to 5 days.
The larval stage lasts up to 14 days, during
which time they consume large numbers of aphids,
scale insects and other soft bodied insects.
Pupation lasts 5 to 6 days followed by adult
emergence.
The adults are rather long lived with some beetles
living up to 3 years.
At least two generations with a partial to
complete third generation, occurs each growing
season. In
the fall when the host plants begin to dry and
cooler weather approaches adult beetles begin to
seek overwintering sites.
They are attracted to vertical walls or
cliffs where they seek shelter in cracks and
crevices.
Once one lady beetle lands, many others may follow
in an aggregating behavior.
Behavior:
The feeding habits of the
multicolored Asian lady beetle (MALB), are for
the most part not well documented in North
America.
They are primarily arboreal and spend a great
deal of their time in the upper canopy of trees.
Thus, we have little information on their
feeding activities.
In 2001 the soybean aphid was quite
abundant throughout the Midwest and the lady
beetle population exploded causing numerous
complaints from home owners and fruit growers.
Control:
Since the MALB is not a native
species, few diseases or parasites have
been associated with this beetle.
Adult beetles have been
associated with vectoring fungal
pathogens and therefore their
aggregating nature may be favorable to
the dissemination of bunch rot and other
diseases from one grapevine to another.
Current pesticide recommendations may be found Here