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Asian lady beetle (Photo by USDA) |
Asian lady beetles, everyone's least favorite harbinger of fall, are also an invasive species. Although these beetles aren't as destructive as the emerald ash borer or as decimating as soybean rust, they still cost homeowners money.
“The key to controlling Asian lady beetles is to keep them out of the house in the first place,” says Tim Gibb, Purdue Extension entomologist. “Putting a preventative insecticide on the outside of the home in the middle of October will do wonders in keeping the pests from appearing inside the home later.”
Gibb says it takes about $30 to purchase enough insecticide to treat a home, but not treating can be more costly in terms of time and frustration. If left untreated, beetles can congregate by the thousands inside homes. When they do get inside, Gibb's best advice is to vacuum them up.
Marshall County resident Doris Barden battles Asian lady beetles every year. “I was vacuuming those things out of my windows and off the walls, light fixtures and the ceiling,” Barden says. “I would do it when I got up in the morning, when I came home from work and throughout the evening. For the couple of weeks when they were really bad, I probably vacuumed an hour-and-a-half each day, but it felt like three hours.”
Gibb says Barden's two-story white home is an ideal attraction for the beetles. “Their native habitat includes high cliffs,” Gibb says. “After feeding during the summer, the beetles would head toward these tall outcroppings or cliffs and get into the cracks and caves to pass the winter. We don't have many cliffs in Indiana, but we do have tall, two-story homes that are light-colored, with windows and shadows that look like cracks or caves to the beetles.” Rural homes that fit this description often appeal even more to beetles because of their proximity to fields and forests that harbor aphids, the beetle's main food source.
The Asian lady beetle is a little different from other invasive species, because it was purposely introduced. Gibb says the U.S. Department of Agriculture introduced it to control aphids at several locations during the 1990s.
By many accounts, the introduction was a success. “These beetles actually do their job,” Gibb says. “We get good aphid control, but what we didn't bargain for is the obnoxious overwintering behavior.”
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