Blue Ridge Country - November/December 2017 - 12
She's No Lady
Why do Asian lady beetles invade Blue Ridge homes in winter?
by Nancy Henderson
If pesky swarms of black-spotted, orange insects are invading your home, like they do every year, take heart, says
Lee Townsend, extension entomologist at the University of Kentucky. It won't always be like this.
"When they first show up, the first few years they're
around, they tend to just be out of control in overwhelming numbers," Townsend says of the Asian lady
beetles that appear in droves in late fall and winter.
"Then things tend to settle down. You'll see a few, but
not the massive infestations."
A native of Asia, the hardy bug with few natural enemies presumably hitched a ride on a Japanese freighter
that docked at a Louisiana port in the 1960s. Coincidentally, pest control experts were already releasing them
in Georgia, South Carolina and other states to get rid
of insects that were damaging pecan groves and apple
orchards. The first attempts were unsuccessful, but
the Asian lady beetles were soon chomping their way
through the Southeast and beyond.
"It likes forested areas, and the Blue Ridge region is
forested," says Townsend. "So it's just an ideal habitat
for the Asian lady beetle to thrive."
By the 1990s, the ladybugs had spread like kudzu,
taking over as both a beneficial import and an annoyance. "It's got kind of a split personality in terms of being very helpful for some things but a nuisance in the
fall," Townsend says. "And that basically has to do with
its behavior for spending the winter."
All adult lady beetles overwinter in large clusters,
with most indigenous species gathering at the base of
trees where they're not readily noticed. The Asian type,
on the other hand, is visually attracted to vertical surfaces and contrasting colors. "So a light-colored house
on a hill, surrounded by woods, is ideal for them," says
Once they land on a building, the insects crawl into
cracks and crevices around window frames, doorways or
exterior attic entrances. They are most active in late afternoon, when the temperature is warmest and the sun
hits the structure's surface from the west and south.
"For us [in Kentucky], it's around Halloween when
we tend to see the beetles really start to fly to their wintering sites," says Townsend.
Asian lady beetles pose several problems. They can