Stink Bugs Do More Than Just Stink

Living in Virginia it is hard not to be acquainted with a relatively new pest that invades our homes and offends our olfactory senses.  That’s right, we’re talking about Halyomorpha halys. Of course to the rest of us, that means we’re talking about the stink bug.  This bug is also called the east asian stink bug, the yellow-brown stink bug, or the brown marmorated stink bug.  Whatever you call it, we can all agree that having these pests invade your home stinks!

Oddly enough this bug which is very common in our area, is a new resident of the mid-Atlantic region of the United States.  According to PestWorld.com, the first positive identification of a stink bug in the United States was of a bug collected in Allentown, PA in 1996 which was not identified until 2001.  It is presumed to have hitched a ride on a cargo ship from Asia sometime before 1996.  The bug did not become a significant pest until 2004, and Virginia is clearly ground zero for the invasion. The stink bugs have spread throughout the mid-Atlantic region with virtually no resistance since there initially was no natural predator of this invasive species.

To most of us the stink bug is just a smelly nuisance, but it turns out to be a much bigger problem for the agricultural industry.  According to an article in phys.org, it has caused millions of dollars in damage to Virginia crops: apples, grapes, soybeans, corn, tomatoes, green beans, and pepper plants.  Virginia Tech Associate Professor of entomology Tom Kuhar said, “This is the one insect that has been all encompassing in the sheer variety of plants it attacks. We have very few agricultural commodities that this bug does not attack.” 

Crop damage aside, the average homeowner experiences these bugs as they make a steady invasion of their homes and walk slowly along walls or buzz loudly as they fly past our heads.  Interestingly enough, the main time of year that stink bugs begin to invade our houses is around the fall equinox in October when the bugs are looking for places to winter.  Some houses have reported tens of thousands of the bugs in various crevices within their homes.  The bugs seem to love small cracks. 

Many websites are out there promoting products to trap stink bugs, but after my conversations with a professor of entomology from Virginia Tech who studies the bugs, I think the most promising idea for trapping the critters is a homemade solution involving layers of cardboard with small gaps between sheets.  Here is a good video of a man who walks you through exactly how to make a good version of this stink bug trap.  

Feeling overwhelmed?  Well, there is hope. A natural predator has been found. In 2005 scientists began an intensive investigation into the possibility of finding natural predators of the stink bug. The experiment was fairly simple:  put stink bug eggs on a card, place the card outside in various areas, and see if anything harmed the eggs.  In 2014, something surprising was found.  It turns out the natural predator of the stink bug from its homeland in Asia had independently made its way to America. This bug is a tiny bug the size of a grain of black pepper which has been given the common name by U.S. scientists, Samurai wasp (Trissolcus japonicus).  This bug seeks out stink bug eggs and lays its eggs inside of those eggs.  The wasp babies feed off the stink bug babies inside the egg thereby neutralizing the offspring of our smelly pest.  It is predicted that as time marches on, this natural predator will help normalize the stink bug population and reduce its negative impact on our lives. 

It looks like our new, smelly neighbor is here to stay.  So, we will just have to get used to the invasion of these little critters into our homes each fall and hope the tiny samurai warriors (wasps) continue in their successful campaign against them.  Just remember, next time you see that little bug plodding along your wall or buzzing by your ear, resist the urge to squish it…at least until you relocate it outside!

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