What are all those little
bugs?
If you live
in the United States, your home is probably being invaded by swarms of lady beetles.
Most of us thought these were the harmless "lady bug". But we were
wrong!
Many people
are wondering what they are and what to do about them. Here are the
answers from the Missouri Department of Conservation.
Over the last
few years, many Missourians have been encountering thousands of lady
beetles "swarming" around and inside their homes. This is not some bug
that's gone berserk, but actually an insect that is new to Missouri. The
multicolored Asian lady beetle was originally released into some southern
and eastern U.S. states several years ago as a predator to control aphids
on trees. None were released in Missouri, but the beetles have spread here
from other areas.
There are
about 400 species of lady beetles in the U.S. Most of these are native to
the U.S., and because most feed on insects that attack plants, they are
generally considered to be beneficial insects. However, the Asian lady
beetle has become a major nuisance because of its swarming behavior. These
insects congregate in the fall as they try to find sheltered places where
they can hibernate during the winter. Then on warm days in early spring
they congregate again in huge numbers as they come out of their over
wintering sites.
In their
native range in Japan, Asian lady beetles swarm around cliffs to search
for crevices for over wintering sites. However, houses and other buildings
seem to be attractive alternatives to cliffs. These beetles enter homes by
slipping through cracks around doors and windows or through attic vents.
Lady beetles do not reproduce indoors during their hibernation period.
They do not harm humans or pets, although at times they can give a bit of
a nip by biting.
The best thing
you can do for this problem is prevention. Caulk up all crevices around
doors, windows, and utility pipes. Make sure you have tight-fitting
screens on windows and attic vents. You should especially concentrate on
openings on the south and west sides of the house, because those are the
warmer areas where lady beetles are more likely to gather. If you already
have lots of beetles inside your house, about the only thing you can do is
vacuum them up and dump them back outdoors, preferably in a sheltered
place a long distance from the house. Avoid squeezing or crushing the
beetles, because they can emit a fluid that can stain carpets or drapes.
Spraying with insecticides is usually not effective, and trying to use
enough insecticide to have some effect just adds a high level of toxic
materials to your home.
The Asian lady
beetle has been introduced into the U.S. several times since 1978. Since
then, they have spread to many parts of the U.S. and Canada. They were
first found in Missouri in 1993 in Carter and Wayne counties, but have now
spread throughout much of the state. It is difficult to predict what
impacts we will see in Missouri as the Asian lady beetle becomes well
established here. Eventually native predators may provide some measure of
control on lady beetle populations. Recent research in North Carolina
indicates that as much as 25% of lady beetle populations were parasitized
by a tachinid fly.
So if your home is being covered by these
new "Lady Bugs", you should consider this practical guide to pest control
that is safe for both the user and the environment.
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