Each fall, it is common to see large numbers of multi-colored Asian lady beetles (orange is the dominating color) clustered around and invading homes. The beetle originated in Asia. Its spread is believed to be related to organized releases as biological control agents for aphids during the 1970s and 80s. Today the beetle is widespread.
Generally, these pests are harmless nuisance pests. However, serious problems can occur in such locations as doctors’ and dentists’ offices. Repeated exposure to the beetles has caused allergic reactions in a small number of people.
If provoked, the beetles can bite or bleed from their joints, giving off a foul odor, which is why birds will not eat them. They can also stain carpets, walls or curtains.
While it looks much like your average ladybug — oval, convex, 1/3-inch long and pale orange in color with various numbers of black spots on the wing covers — an M-shaped marking on their pronotum separates this beetle from the beetles we have grown up with.
The beetles can live for two or three years, and do not breed inside homes. When cool weather approaches, they move into protected areas, like leaf litters; underneath rocks, boards or logs; and caves, after the first frost. Those that move inside buildings for overwintering usually select the west or southwest side of a building as the initial congregation area and then move to higher locations.
Xing Ping Hu, an entomologist with the Alabama Cooperative Extension System, said, as with many insect pests, prevention is the key to keeping unwanted beetles from getting into homes. One of the best ways to keep them out is simply to take steps to block their entry before they get inside. Sealing and/or caulking homes’ entry points will help.
Here are some other ways to prevent beetles from entering your home:
* Make certain doors are tight-fitting.
* Install door sweeps or thresholds at the base of all exterior entry doors.
* While lying on the floor, check for light filtering under doors. Gaps of 1/16-inch or less will permit entry.
* Make certain windows and utility openings are properly sealed.
* Caulk cracks around windows (also around doors, fascia boards, etc.). Use a good-quality silicone or acrylic latex caulk.
* Check where pipes and wires enter the foundation and siding around outdoor faucets, gas meters, clothes dryer vents, and telephone, cable or satellite TV wires for gaps. Holes can be plugged with caulk, urethane expandable foam, steel wool or copper mesh.
Even the most tightly sealed homes may have problems with these insects getting inside. There are a number of insecticide sprays that can be applied to the outside of buildings during late September or early October to kill and repel the beetles before they get in. The most effective sprays are synthetic pyrethroids like permethrin, cypermethrin, cyfluthrin, delta-methrin and lamda-cyhalothrin. When shopping for these chemicals, look at the active ingredient of the insecticide. (Note: Enforcer® Asian Lady Beetle & Box Elder Bug Killer contains sumithrin and tetramethrin, also kills mosquitoes, can be used indoors and outdoors, and is available at your local Quality Co-op.)
If the active ingredient ends with "thrin," it is in the pyrethroid family and should work well in cooler fall temperatures. Concentrate applications of these products along doors, windows and overhangs on the south, west and east sides of the home.
Make sure the sprays will not stain siding. People may hire a professional pest control company to make the application.
When all else fails, a vacuum cleaner or broom is often the best response once beetles have come indoors. Just make sure to empty the vacuum outside because the majority of the beetles will still be alive and crawl back out of the vacuum cleaner.