The Beetles’ Fall Tour
No, not the Fab Four — more like the Fab Gazillion. Swarms of thousands to perhaps hundreds of thousands of Asian lady beetles, Harmonia axyridis, (those cute little ladybugs) are coming, not to a location near you, but to your location.
This tiny bug has a penchant for swarming in the fall looking for good overwintering sites. Across Asia from Siberia to Japan, those sites are mostly mountainsides, cliffs and rock outcroppings. Here in the good ole’ U.S. of A., those sites are too often homes, businesses and/or other man-made structures.
We will probably never learn our lesson bout messin’ with Mother Nature. Asian lady beetles were brought to this country in the late 1800s to early 1900s as biological control agents targeting pests like aphids and others. It seems it took the Asian beetle a little while to get established. The first established population was recorded in Louisiana in 1988. Since then they have spread across the U.S. reaching Canada in 1994.
When I first researched these little buggers back in 2001, I spoke with Jim Costa, professor and entomologist (we can now add author and director of Highlands Biological Station to his titles) at Western Carolina University. Costa noted that these ladybugs emit an aggregating pheromone in the fall. This pheromone is not especially intense but its effectiveness is multiplied by numbers. The bigger the swarm, the smellier the brew.
Homeowners are likely to first notice ladybugs on the outside of their home, flitting around windows or doorways or crawling on outside walls. But unless your home is airtight it is only a matter of time before you notice that spot on the wall above the kitchen window is moving.
What to do? If you consider exterior pesticide application by a professional pest control company, here are some things to think about. If you spray too early, the insecticide is not effective when the beetles arrive. If you wait until they arrive, many will make it into interior spaces and the spray will be ineffective. And, of course, you are increasing the toxin level around your home.
Interior application is even trickier. These little bugs are hard-nosed and hard shelled. They must be sprayed directly or crawl across treated surfaces for the insecticide to be successful. Once again, this increases toxin levels, and now, it’s inside your home.
One way to deal with ladybugs inside your home is to vacuum them. For those with a soft spot for these cute beneficial creatures, a handkerchief can be placed between the vacuum hose and the dust collection bag or area and the ladybugs can be trapped and relocated.
Whatever you do, you don’t want to agitate or squash these critters. This triggers a defensive reaction known as reflex bleeding. The ladybug emits a foul smelling, foul tasting (if you’re a predator) fluid that can stain walls and/or fabrics.