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Timothy J. Gibb, Entomology Department, Purdue University
|Asian Lady Beetles on Siding
(Click on small image to view a larger image.)
Who is not sick and tired of living all winter long with "lady beetles"?. Many Hoosiers have complained about "lady bugs" making a nuisance of themselves all winter long. They swarmed homes in the fall, reappeared several times inside the home during the winter whenever temperatures warmed up, and now they are at it again, making a nuisance of themselves once more. They fly around lights and crawl across ceilings, and emit a foul smelling odor when handled. Even outside now they are buzz around porches and doorways and bump into people working in the yard. Desperate Hoosiers are asking "What chemicals can be used to finally kill the little buggers?". Revenge will be sweet !! As much as I hate to burst a bubble, the correct answer will afford no revenge. While it might make one feel good to spray some kind of lethal insecticide, see them fall to the ground, flip onto their backs, put all six legs up in the air, twitch their little antennae one last time before finally dieing, now is not the best time of year to control lady beetles.
Someone smarter than me once said "To defeat your enemy, you must first know your enemy". I don't know what that means to a military strategist exactly but what it means to lady beetle management is that one must first understand the life cycle of the beetle. Here are the pertinent facts. First, remember that ladybeetles pass the winter as adults. In the Fall time, they are attracted to light colored buildings and especially to those areas that are illuminated by the sun. For this reason, beetles usually first appear on the southwest-facing sides of light-colored buildings close to wooded areas. Once several beetles have settled on a suitable site, they release an air-borne, chemical, signal which attracts even more beetles. Congregating begins in mid October and seems to reach its peak by the end of the month. During this congregating activity, hundreds of thousands of beetles may appear around homes. When outside temperatures fall, the beetles move into tight cracks and crevices such as under siding or in wall voids, or cluster tightly into the corners of attics or garages. Once there the beetles eventually find their way through cracks and crevices, natural breaks in window sills, door jams or foundations. There the beetles essentially laze about in a hibernation-like mode, not eating nor moving much, for several months. When out of sight during the winter months, homeowners are often fooled into believing that the beetles are gone. That is, until the first warm days of late winter or early spring, when the beetles seem to come to life again and begin crawling about.
The beetles are now, Spring of 2002, looking for ways to get back outside where they can fly off to trees or wherever they like to live during the summer months. Be patient while they are finding their bearings. Assist them in their efforts by sweeping them out. Keep in mind that it is the Fall time that we need to remember the headaches we endured this winter. October is the time to control the beetles by preventing them from entering the home. Stay tuned for 'revenge' recommendations in September.
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Last updated: 17 April 2002/tlm.
The Plant & Pest Diagnostic Laboratory at Purdue University.