The ‘When’ in
Asian Lady Beetle Control
Tim Gibb, Insect Diagnostician, Department of
Entomology, Purdue University
Most every Hoosier
has had some experience with Asian Lady beetles or ‘ladybugs’ and
it has not always been considered positive. In some cases
literally thousands of annoying and smelly lady beetles are found
flying and crawling inside a home or garage during late fall or
winter. One common name of this beetle is the
Halloween lady beetle. This may be an appropriate name for
two reasons. First, with a little imagination, some of the
beetles are reminiscent of pumpkins (see first picture).
Granted, some are reddish and many bear any number
of different spots but still there are some that are solid orange
and rounded, much like the top of a pumpkin.
Secondly, and perhaps more convincingly, the
timing of Asian lady beetle occurrence near homes is coincidental
with the Halloween season. The beetles congregate in late
fall and a particularly troublesome at tall, light-colored buildings
where they first appear on the southwest-facing sides close to
In most years congregating begins in mid October
and usually reaches its peak by the end of the month. Congregation behavior in
the beetle is usually initiated by any cold weather event in October
that is followed by very warm temperatures. During the ensuing
warm days, beetles begin to gather by the hundreds of thousands
around homes, creating a serious nuisance.
Knowing when beetles will appear and being
ready for them is half the battle with these pests. Specific
control options depend, to a large extent, on the number of beetles
and the level of tolerance by occupants in any given home.
Sweeping them up and disposing of them may
be the best option for a few beetles. Vacuuming
also will work and nozzle extensions will allow access to those
on the ceiling or in hard to reach places.
Sometimes, chemicals can be used to assist
homeowners in controlling Asian lady beetles. Using pesticides
as a perimeter treatment during late fall will help prevent beetles
from getting into the home. Choose materials
that will leave a long lasting residue. Wettable powders, micro-encapsulated
and suspended concentrate formulations seem to work best. On the outside
of the home, pest control operators have used long-lasting/rapid knockdown chemicals
such as Demand or Suspend with excellent success. Talstar, Tempo, or Demon
may also be used. These materials may afford protection for up to 1 month,
depending upon the site of application. Homeowners may use Sevin or Malathion
at rates labeled for “household invading” or “occasional” pests,
but must be ready to re-apply as needed. In either case,
the key to control is to apply the chemicals to the outside of
the home in October while the beetles begin to congregate but before they enter
In most circumstances, a combination of several control methods
is the best answer to Asian lady beetle problems. Preventing beetles
from entering the home is the best and most effective control practice.
Sealing them out by caulking cracks and around utility service
openings, fixing broken window screens and door jams, plugging
cracks in the foundation or roof, and other similar exclusion-type
activities will help prevent the lady beetles from entering in
the first place. Physically removing the beetles as described above
with a vacuum or sweeping them out is always a good control method.
A combination of several control methods is
the best answer to Halloween lady beetle problems, but if you
choose to use pesticides as a perimeter treatment, they must
be in place 2 – 3 weeks
before Halloween arrives, in order to be effective.