“Home Invasion,” by Kathryn Schulz. The New Yorker, 3/12/2018.
If you only know a stinkbug as a dime-sized, flat, slow bug, you have not dealt with a home invasion by thousands of them. But you will. Eventually, you will. They are relatively new to America—only about ten to twenty years—but they have been busy making more stinkbugs.
Imagine coming home one night, flicking on the light, and seeing hundreds and hundreds crawling on the walls and on every surface. Look behind a picture, and find hundreds more. Shake out the drapes and still more fall out. They’re everywhere, on top of furniture, under furniture,
What are you going to do? Spray them with a strong, general pesticide? Not in your house. Squash them? That’s when they stink. The best you can do is shoo them outside and hope more are not coming in. Finally, when you think the last are gone, get in bed, turn off the light, and feel them drop on your face from the ceiling (they like heights and are attracted to warmth). For days after, you will find them inside of drawers, in piles of clothes, inside appliances, sharing your bath. The question is not if this will happen, but when.
(I would suggest sucking them up in a shop vacuum and opening it outside.)
My original technique for individual stinkbugs was as good as any. I grabbed them with my hand and threw them out the front door. My wife often said I should kill them, but killing them would not matter to such a huge population and would only stink up my hand.
First, a definition that is fun to know: frasses is insect poop. (Seventy years ago, my sister would love to call me that.) Then, a definition you need to know: “bug” is not synonymous with “insect,” but is a subset of insect. A bug is an insect that has developed mouth parts that pierce and suck, as opposed to mouths built, like ours, to chew.
A stinkbug, as its name says, is a bug, but it can eat a wide variety of things: 15 kinds of trees, such as birch trees, junipers, and maples, plus things we eat, too: broccoli, asparagus, tomatoes, eggplants, grapes, apples, and pears. And that is only the beginning. Scientists have discovered more than 250 other foods they will eat. The wide variety of food makes it difficult to quantify its damage, but no one disputes its significance. The loss in New Jersey peaches, the fourth largest producer, was 60 to 90% in 2010.
Its full name is: brown marmorated stinkbug (marmorated means veined or streaked like marble.) Just last year I crushed one to smell the stink people talk about. I found it to be pleasantly chemical or medicinal; not especially objectionable. But then, I’m a chemist. Most people equate the smell with cilantro.
The stinkbug is native of East Asia where it is kept in check by predators. They probably came to America in a shipping pallet. In 1998, a man from Allentown gave several to Karen Bernhard, an entomologist at Penn State for identification. She sent samples to Richard Hoebeke at Cornell, who properly identified them as the first stinkbugs found in the Western Hemisphere. That was in Pennsylvania. In 1999, they were found in New Jersey. By 2004 they were found in West Virginia and Delaware. The rest is history. They have since migrated as far as Europe, where France calls them the Devil’s thumbtack.
The stinkbug is resistant to pesticides for several reasons. Its waxy shell is difficult for pesticides to penetrate; its relatively long legs keep it standing above surfaces; it eats from the interior of plants where pesticides do not penetrate.
Stinkbugs can survive winters outdoors but prefer to move inside—in the hundreds, in the thousands. When one gets inside, it emits a pheromone that attracts others, and can be detected by other stinkbugs a year later. In the winter, they go into an insect form of hibernation where their activities slow down. This often means they dribble out into view a few at a time, rather than in a flood.
Numbers matter. Seeing a dozen geese fly across the fall sky in formation is far different from seeing thousands of them gathered in a field. One wildlife biologist in Maryland counted all of the stinkbugs he killed in his own home. He stopped after six months at 26, 205. Corn and soybean farmers have had to turn on the windshield wipers of their combines.
Despite the stinkbug’s size, they can penetrate any opening larger than 7 mm, which means it is virtually impossible to stinkbug-proof a home. They prefer heights. and tight, secluded places, such as in stacks of old newspapers or between folds of cloth. Inside, they will move more to the higher floors and search out a linen closet or folded blankets. During the winter, they settle down to a slow pace similar to hibernation where they need little food. Any pesticide designed for indoor use is almost certain to fail.
Some say the best way to kill them is to place them in a baggie and freeze the baggie. Not very practical, but what else can you do?
In East Asia, their numbers are kept in check by a predator, the samurai wasp, but importing predators has had more disasters than successes. No one, as yet, is suggesting that as a cure, although some people have suggested burning down their infected home.