By Staff
Several weeks ago I wrote about the Asian lady beetles and what a nuisance they are when they ascend on our houses. A nearly equal nuisance is the box elder bug. They're those half inch long, flat bodied, black bugs with red stripes you're probably now seeing crawling all over the sides of your house. Like the Asian lady beetles they often accompany, box elder bugs gather in the fall to search for a secluded spot to spend the winter. The only thing that makes them a slightly lesser nuisance than Asian lady beetles is that box elder bugs rarely bite. Otherwise they cause all the same problems like staining the walls, ceilings and drapes with their excrement and, in the event of a mass die off in your house, stinking up the place.
As its name suggests, the box elder bug goes hand in hand with the box elder tree. This tree is the main food source of box elder bugs. The box elder has long been utilized as an ornamental tree. I've mostly noticed them in the vicinity of old homesteads and almost never out in secluded woodlands. From that I've always assumed box elders were not native to this country, but rather introduced from somewhere abroad, along with their accompanying box elder bugs. I was quick to blame this nuisance insect as yet another example of man mucking around with nature with detrimental results.
I recently discovered my assumptions were wrong. The box elder is native to North America. It's a member of the maple family and, in fact, its true name is ash leafed maple. Its nick name comes from the soft, white wood resembling that of boxwood, a Eurasian evergreen, and the leaves resembling those of the elderberry bush. It grows best in moist, fertile soils as found in our yards. It's a fast growing, fairly small tree which makes it desirable as an ornamental tree. Box elders are uncommon in woodlands because they're comparatively short lived and their low height allows them to be shaded out by other larger species.
That's not a problem for the box elder bug though. While box elder trees are their food of choice, they also feed on silver maple and several other maple species as well as ash trees if they get desperate enough. The box elder bug has a long, biting snout used to pierce the leaves, flowers and seed pods. It then sucks the juices seeping from the severed area so it does not damage the tree itself. They are capable of biting through human skin but very rarely do so. Perhaps they're high on the bug intelligence list and can reason that assaulting something a million times your size guarantees you'll be a squashed bug. Okay, perhaps not. Anyway, it's interesting that box elder bugs swarm all over female trees, those that produce flowers and seed pods, while only a few outcasts choose male trees for lunch. Juice from the leaves is the primary food source, not the flowers and pods, and no one has figured out why girl trees are preferable. Just one of those things, I guess.
Other than leaving unsightly excrement spots, box elder bugs do no damage to the house itself. However, it's somewhat disconcerting when they attempt to take over the entire house. Control is similar to that for Asian lady beetles. Seal up all the joints, cracks and crevices that provide them access into the house. Contact insecticides such as Sevrin kill them if you can get it where the bugs come in contact with it but that's easier said than done. Few of us care to hose down our houses with hazardous insecticides, anyway. Bug bombs are ineffective. Individual bugs can be vacuumed up but empty the bag outside immediately or they just crawl back out. Bugs on the walls and windows can be knocked off into a bowl of water which keeps them from flying away. I've heard that spraying individual bugs with a dish soap and water solution goofs up their breathing and kills them but I haven't tried that one. I've resigned myself to accepting them as just another of Ma Nature's less desirable children. Carpe diem.