Asian lady beetles are on the march, right into Kansans’ homes
MANHATTAN, Kan. – Over the next few weeks many homes in Kansas – especially in rural areas – will be invaded by an intruder. What is it? Why is it here? Is it harmful and how can I stop it? The intruder is the multicolored Asian lady beetle.
“They are bright orange with spots, but they have kind of a dark black inverted W right behind the head on the thorax,” said Jeff Whitworth, entomologist with K-State Research and Extension. “If you see those things it is the multicolored Asian lady beetle.”
The beetles have mouthparts intended for chewing, but they can bite people and animals. People working in farm fields where aphids are present have a greater chance of being bitten.
“What we are seeing this year is something we haven’t seen for five or six years,” Whitworth said. “The last time there was an outbreak of soybean aphids in 2008 we saw a buildup of these multicolored Asian lady beetles at the same time because they are feeding on aphids.”
The beetles were originally imported into the United States by the U.S. Department of Agriculture as a biological control. They are considered a beneficial insect, particularly in alfalfa, soybeans and sorghum where they feed on different aphids, which damage the crops.
“Last year and this year we had a buildup of sugar cane aphids which has led to massive populations of the multicolored Asian lady beetle,” Whitworth said.
“The Asian lady beetle does not eat crops,” he added. “They only eat the bugs that eat the crops, especially aphids. Right now there are still a lot of them in sorghum fields because that is where the aphids are.”
As the aphids disappear and the days get shorter, the beetles will move to homes, sheds and garages in rural areas. Most often they can be seen gathering on the south and west side of the building.
“We have a lot of them accumulating in houses right now, but we have more to come as sorghum is cut and the sugar cane aphids die off or migrate,” Whitworth said. “They (Asian lady beetle) are beneficial for the most part but they can also be a nuisance.”
“I often get calls asking if there is anything that will eat these bugs,” Whitworth said, adding that ironically that dogs seem to like to eat them. They are not there to feed on the animal and they don’t carry any diseases. They are just a nuisance.
He recommends removing the insects and caulking over cracks. Make sure all screens fit to keep the beetles from entering homes and other buildings. If they do get in, they can be removed with a vacuum. If the vacuum does not kill them, they can be released outside.
The beetles aren’t on the label of a pesticide, Whitworth said, because they are not considered an agricultural pest. However, if you use any crack or crevice treatments for spiders and the residual is around, that will kill the lady beetles, too. If you remove them and put a crack and crevice treatment around your house it will help.