Ahh, autumn in Ohio: brilliant fall colors, hayrides, jack-o-lanterns … and maddening swarms of Asian lady beetles. Yes, Asian lady beetles, the rub to an otherwise beautiful time of the year.
Praiseworthy in the spring and summer months for feasting on a variety of garden pests, the “good” beetle becomes the “pest” once Ohio’s weather begins turning cooler and the lady beetles’ search for shelter leads them inside our homes. Clearly, their inward trek is one fall migration most of us could live without.
Asian lady beetles – ranging in color from yellow to dark orange and sporting an average of 16 irregularly shaped spots on their domed backs – should not be confused with Ohio’s state insect, the convergent ladybug (actually a beetle, as well). Native to Ohio, our state insect is more polite and over-winters outside under logs, leaves and bark.
Like Houdini, Asian lady beetles seem to appear out of nowhere. Often congregating on ceilings, windows and around light fixtures, the lady beetle enters through small gaps or cracks in siding or masonry and through attic or foundation vents. They crawl in under defective weather stripping and, on warm days, take the easy route through open doors and windows.
Here’s the good news about Asian lady beetles, according to Barb Bloetscher, an entomologist with The Ohio State University. “They’re harmless, if annoying,” she says. This time of year Bloetscher takes a number of calls each day about the pesky pumpkin-colored home invader. She’s quick to assure callers that lady beetles do not reproduce inside houses and, in most cases, will not live to see another spring.
Additionally, Bloetscher and other experts say Asian lady beetles do not cause any structural damage to homes, like termites or carpenter ants, nor do they destroy fabrics.
This does not mean you want these critters in your house. Try sweeping them up in a dustpan and depositing them back outside, preferably near protected areas, such as rocks or a log. Use care, however, when removing these unwanted guests from furniture and draperies. When squashed, the lady beetle emits a greenish-orange fluid that can stain fabric and walls.
Not feeling so charitable? You can vacuum up the offenders, but make sure you empty the bag immediately. As the beetles die and decay, they can leave behind a permanent, unpleasant odor in the vacuum.
Slightly larger then their Ohio cousins, Asian lady beetles were imported to the United States to combat insect pests in trees. Bloetscher said that today, lady beetles have added a variety of agricultural pests to their diets, such as the soybean aphid.
Considered harmless to humans, the Asian lady beetle is a true friend to the farmer. In its lifetime, one lady beetle will eat thousands of aphids and other plant-damaging insects, thus promoting healthy plant growth and reducing the use of pesticides.
Love them or hate them, the Asian lady beetle certainly knows how to attract attention. Perhaps the best solution is peaceful coexistence: If you promise not to squash them, they’ll do you a favor and devour the tasty aphids threatening your houseplants!