Imported Pests: Ladybugs and Stink Bugs
I'm not an entomologist. I am not an exterminator. In other words, I'm no expert on insects, but I think I'm an expert at looking for weird stuff going on in buildings. Of course, I'm always on the lookout for wood damaged by bugs like termites and carpenter ants. In the past decade, I couldn't help but notice a major increase in two specific types of bugs in buildings--ladybugs and stink bugs.
Now when I see something happening with increasing frequency on my inspections, even if it doesn't seem to have any impact on the building's structure and systems, I get curious and try to find some answers. Inevitably, when my clients see piles or swarms of bugs, they'll ask me for an explanation. If I can give them a reasonable answer, they think I'm smart.
I used to rarely see them inside of buildings. Now I regularly find piles of them on window sills, groupings on closet shelves and the occasional individual marching up and down walls. I was told it was because of the recent trend of gardeners going organic. You can purchase ladybugs from a garden supply or through mail order and then release them as a form of natural pest control (they eat the really little bugs that damage your garden plants). It sounds plausible, but don't go punch the little old lady planting bulbs next door. It's a much larger plot that likely lead to the "ladybug invasion."
Ladybugs: Not the Usual Suspects
It turns out that what I've been seeing aren't the typical ladybugs that I would find smiling on my daughter's sticker book. These are actually Asian Lady Beetles and if you look close, you'll see that they're not really red, but differing shades of orange. Some have black spots and some don't. They're originally from Southeast Asia. They were periodically released by the U.S. Department of Agriculture in an attempt to control aphids in fruit and nut trees. These releases occurred at a few various times during the 20th century in several Mid-Atlantic States, a couple in New England, several in the Southeast, one Midwest state, and two states on the West Coast. The USDA claims they were unsuccessful in establishing the beetle. Maybe I should check the immigration records at Ellis Island.
The good news is that they're really just a nuisance. They typically don't harm buildings, people, or pets and don't carry disease. They're most likely coming into buildings one or two months before winter really sets in. They're not breeding while in your home. They're just hanging out inside and exit in the spring to feed on aphids all summer.
I remember messing around with stink bugs as a kid. The bugs marching around boldly in our homes aren't the same species. This East Asian invader, the brown-marmorated stink bug, showed up in 2001 about 10 miles from where I now live. They quickly spread throughout Pennsylvania, New Jersey and then Delaware. They're now appearing in many other states, possibly even as far as the Pacific Northwest.
Just like the lady beetles, these bugs want to overwinter in our homes. They're not known to be harmful, just a nuisance when indoors. If you disturb them, they stink. Outdoors, they're much more than just a nuisance for gardeners and their plants--they damage fruit and leaves.
That's the official entomological phrase for the best method of dealing with these invasive pests. Both species of these insects can find their way in through some very small openings. Torn screens, gaps around windows and doors, gaps were siding meets the foundation, trim or chimneys and utility pipes/cable penetrations are some of the more common places that need attention to help keep these bugs outside.
William Kibbel III is a home inspector and restoration consultant specializing in historic residential and commercial buildings. He is vice president of Tri-County Inspection Company, serving Southeastern Pennsylvania and Central New Jersey.