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 wooded areas.

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 the home.

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.

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