Asian lady beetle infestation is upon us
They are out there all summer, living in the woods and fields, and now they want a snug place to spend the winter.
Your house, cabin, camper or deer shack will do just fine, thank you.
Orange Asian lady beetles, the little buggers who have replaced ladybugs across much of the landscape, are making their annual trek from the outdoors to indoors, and the infestation seems worse than ever.
"We've had them before, but never this bad. It's been pretty nasty," said Dan Woodhull of South Range, who had hundreds of the beetles in his house in recent days.
Reports of beetle outbreaks are coming in from across the region.
"It does seem particularly bad this year. We'll have to wait and see if this is just an early rush or if there really are this many more of them,'' said Larry Weber, a naturalist. "I left my vehicle sitting out overnight and I had a bunch of them that tried to get into it, all around the door seals."
Asian lady beetles are much the same as field mice, Weber noted, always around but mostly unnoticed until they try to get indoors this time of year.
Experts say the beetles are pushed by diminishing daylight hours to seek winter cover. But they also swarm and fly most often on warm, sunny fall days following the first cold snap—which may be why so many people reported infestations over this past weekend.
"I noticed them for the first time over the weekend. I'm getting a lot of calls on them," Minnesota Department of Natural Resources entomologist Val Cervenka said.
Amanda Glowacki at Guardian Pest Control said many people are calling to say they are grossed out by such large numbers of the orange bugs.
"We've been getting a lot of calls on them this year. That's what nearly all of our calls have been for the last couple of weeks," she said.
Marty Johnson, a technician at Guardian, said he offers an exterior "ground to eaves" chemical treatment for homes that often also reduces beetle numbers inside the house, too. It costs $200. He also offers interior treatments.
"I had them all over my house this weekend, too," he said.
Experts say the best way to get rid of Asian lady beetles is to vacuum them up, but then empty the vacuum or it may start to smell bad. To keep them out of your house, seal up even tiny cracks, around doors and windows, where cable, pipes or wires enter homes, and under fascia, soffits and eaves.
"But they will still find some way to get in, it seems," Weber said.
Woodhull said he turned on his home's air conditioning so the beetles huddled together, and then sucked them up with a vacuum.
The first Asian lady beetle infestation it he U.S. was reported in Louisiana in 1988. Since then the beetle has expanded across the U.S. and parts of Canada. There's still debate if the outbreak was caused by beetles that were intentionally released to see if they might help control plant pests, or if the beetles spurring the outbreak hitchhiked on a freighter that docked in New Orleans. The first big U.S infestations occurred in the 1990s. The first major northern Minnesota outbreaks were in the early 2000s, Weber noted.
Native red ladybugs are considered beneficial because they live on flowers and plants and eat other pests and don't swarm into buildings. But the orange Harmonia axyridis—native to China, Korea, Russia and Japan - can swarm in large numbers, crawl around on windows, walls and ceilings, and sometimes emit a noxious odor and yellowish staining fluid before dying, according to University of Minnesota Extension entomologists. The bug experts say Asian lady beetles are attracted to illuminated surfaces. They tend to congregate on the sunnier, southwest sides of buildings illuminated by afternoon sun.
They don't eat wood or cause damage, experts say, and don't spread disease. But some people say the orange beetles can bite.
Weber, however, says it's more of a pinch. "I don't think they can really break the skin, like a true bite, but they might annoy some people by pinching their skin."
Others report incidents of asthma or allergy outbreaks after an Asian lady beetle infestation.
Asian lady beetles generally lay eggs outdoors under leaves, but may lay eggs inside, too. The average time from egg to adult is about one month and there are multiple generations per year. Individual beetles can live up to three years. They appear to have few if any natural enemies in North America.
Some folks who noticed them in and around their place this fall may see them again when temperatures warm in spring. Awakening beetles may emerge from behind baseboards, walls, attics and suspended ceilings. Because the beetles are attracted to light, they often are seen around windows and light fixtures.