Purdue News

April 3, 1998 Asian ladybugs invade homes, thanks in part to mild winter WEST LAFAYETTE, Ind. -- This winter's mild weather has brought thousands of orange ladybugs into homes in Indiana. Not many people consider them welcome guests. According to Tom Turpin, professor of entomology at Purdue University, the invasion of the Asian ladybugs is something new for Indiana. "These beetles have only been in Indiana for a few years," Turpin said. "For some reason there was a large population of them last summer, and with the mild winter we had, many of them came out of hibernation early. "At my house I don't know if there was a day this winter when I didn't see one of them. That's very unusual." Unlike the more familiar ladybugs, the orange Asian ladybug often likes to overwinter in structures. The problem is that after they have nestled into a seam in the attic, they can't find their way outside again when the weather warms up. "It's like a dog that gets into a yard through a hole in the fence and then can't find its way back out again," Turpin said. "It was much worse this winter because there were many more warm days when the ladybugs would come out of hibernation and begin wandering around." The Asian ladybugs do not feed on or damage anything in the home. They do not bite people or pets, do not infest stored food, and do not destroy household furnishings. "They don't breed inside, either, so all of those that you might find have come in from the inside," Turpin said. To get rid of them, Turpin suggested vacuuming them up. "However, be sure to empty the vacuum bag after each time because live beetles can sometimes find their way out of a vacuum left in the closet," he said. "You know, organic gardening companies sell ladybugs at a fairly high price for biological control of pests in gardens. You could look at that pile of beetles as saving you money. You should just take them out and put them on the garden where they belong." Turpin said the Asian ladybugs were first introduced into several states in the United States by the federal government several years ago as a natural way to control aphids and scale insects on trees. "The government tried three times to introduce them for control of aphids on pecan trees, and each time they all died," Turpin said. "Then some of them came in accidentally through the port in New Orleans and they spread across the country. Our beetles appear to have sprung from the accidental introduction in New Orleans." The Asian ladybugs are different from the familiar red native ladybugs because they will invade buildings. Although the native ladybugs overwinter individually under bark or in leaf litter, Asian lady beetles prefer to cluster together in huge numbers on the sides of homes and other buildings. Eventually, as the temperatures drop, they work their way into the building through small cracks or crevices. According to Turpin, Asian lady beetles are most attracted to light-colored buildings, especially those close to trees or woods. He suggested that homeowners can take these steps to prevent the ladybugs from getting inside their homes and garages: Seal out the beetles by caulking cracks, crevices and utility service openings; fixing broken window screens and door jams; and plugging cracks in the foundation or roof. Use pesticides as a perimeter treatment. Turpin recommended using long-lasting materials such as wettable powders or micro-encapsulated or suspended-concentrate formulas. "You should apply these pesticides by late October or early November," he said. Turpin said that when the ladybugs invade homes, they can do so by the thousands. "I had one call from a couple in Bloomington, and they were telling me that they had thousands of beetles in their homes, and it turned out that the wife was an accountant and after she swept them up each day she counted them. She had about a thousand a day, so they really did have a big infestation." According to Turpin, the Asian ladybug can range from almost red to orange to brown, and may or may not have spots. "They are very diverse morphologically," he said. "They're kind of like people, because they all look different from each other." With typical humor, Turpin also noted that the name ladybug is something of a misnomer. "Half of them are males," he said. Source: Tom Turpin, (765) 494-4568; e-mail, Tom_Turpin@entm.purdue.edu Writer: Steve Tally, (765) 494-9809; e-mail, tally@aes.purdue.edu Purdue News Service: (765) 494-2096; e-mail, purduenews@purdue.edu To the Purdue News and Photos Page