On those wonderful, warm sunny autumn days when people enjoy being outdoors, the multicolored Asian lady beetles enjoy swarming indoors. Walls, windows, doors and ceilings with southern and western exposure often teem with the small beetles as they emerge from their hibernation sites to enjoy the sun's warmth.
"They're harmless," says Stacy Hambleton, Oregon County Extension agent. "But they are a nuisance when they come inside."
The Extension office handles several calls on days when the lady beetles are swarming. James Quinn of Quinn's Pest Control in Alton said he also receives calls about the beetles.. Both recommend vacuuming as the best method of removal.
Quinn cautions that because of the smell they give off when squashed, one should sprinkle some baking soda on the floor, vacuum that, then go after the insects and empty the bag outdoors immediately. There are no chemicals that can totally control them, said Quinn. "For every one you kill, 50 more show up for the funeral," he said.
Along with being a nuisance when swarming, "They will 'nip,' bite, taste -- however you would like to describe it. They are a predatory insect with chewing mouthparts. I describe it as testing to see if you are edible. They do not 'feed' on humans or mammals or plants," said Mike Brown, state entomologist of the Missouri Department of Agriculture.
The beetles (also called lady bugs or lady bird beetles) were introduced into the United States in the late 1970s as a biological control agent. Quinn said they began to appear in Oregon County in 1997. They are a beneficial insect because they feed on aphids, mealybugs, scale and other soft-bodied insects that infest crops and plants. In their native home (Japan, Korea and other parts of Asia) the beetles usually overwinter (hibernate) in cliffs. Light colored buildings have become their hibernation choice in their new home.
The beetles enter buildings through small cracks, vents and poorly fitting window screens and doors. Hambleton recommends caulking outside cracks around doors and windows, putting screens on vents and replacing torn or ill fitting window and door screens. If vacuuming is not practical, Hambleton said sprays containing pyrethrins or pyrethroids may be used in the house, and insecticides such as Sevin may be used for outdoor control.
For those who would like to report beetle sightings, the U.S. Department of Agriculture has a web site for tracking them: http://www.pmcenters.org/northcentral/MA....