Asian Ladybug, Fly Away Home!

When ladybugs first appeared inside our house, my husband and I took it as a sign of good luck. Little did we know that they were Asian ladybugs, and the Asian ladybug is bad news.

The ladybugs that showed up in our house weren’t as red as such beetles usually are, but we thought it was because they spent so much time indoors. So we carefully captured each one and turned it loose outside. When the weather turned bitter, we moved the bugs one by one onto the house plants, hoping they would find enough there to eat and drink.

But the beetles came faster than we could rescue them. Pretty soon I couldn’t vacuum the floor without sucking them up, which made me feel like a bad person. After all, ladybugs are a gardener’s ally and some folks spend big bucks to buy them.

One warm morning we awoke to find the living room windows covered with ladybugs. By mid-day they were all over the room. The same happened the next day, and the next. We couldn’t avoid stepping on them, and they made red stains all over the floor. They also left more spots than flies on the ceiling — the very ceiling we had just painted.

And, despite what the experts say, they have a stinging bite!

This, we decided, was too much of a good thing. Then we found a report from the University of Missouri: In the 1970s, the USDA imported the Asian ladybug (Harmonnia axyridis) from Japan because of its voracious appetite for soft-bodied insects. These beetles were released in southern states and in Washington, Oregon, and Delaware. You can tell they’re the Asian variety, the reported said, because they’re paler than common ladybugs.

Aha!

During fall, these bugs congregate and hibernate in walls, attics, and other dark, undisturbed places. In winter they move into houses to keep warm. “Once the beetle crosses that threshold,” says entomologist Darryl Sanders, “it becomes a pest.” Indeed, a Missouri family swept up a bushel-basket of ladybugs after hiring a professional fumigator.

Sanders claims screens and caulking will keep them out. Apparently he doesn’t have them in his house or he wouldn’t spout such nonsense. All the caulking in the world will not deter these buggers.

The problem, we determined, was the contractor-installed wooden trim around the windows, which covered large air gaps surrounding the windows. The air gaps were providing a nice warm place for the ladybugs to congregate in cold weather.

Gaps, of course, should be filled with insulation and wood filler strips (rather than caulk), not only to keep out ladybugs but also to minimize drafts. To solve the problem, we removed the wood sills and trim around the windows, filled the gaps, and replaced the trim with drywall returns. Now the windows have a nice modern look, are no longer drafty, and — best of all — keep the Asian ladybugs from invading our living space.

Ladybugs may be a sign of good luck, but Asian ladybugs are way too much of a good thing.