Monday, April 23, 2018

Invasion! Washington state under siege from the stink bug menace!

Posted By on Mon, Apr 23, 2018 at 4:37 PM

click to enlarge Invasion! Washington state under siege from the stink bug menace! (2)
Michael Bush photo
Memorize these markings well, citizen! They could mean the difference between feast... and famine.



We open on Karen Bernhard, a horticulture and entomology specialist with Pennsylvania State University, investigating a curious infestation in Allentown. For five years, homeowners had been complaining of bugs in their houses. The residents had seen stink bugs before, but not like this. Not this many. These weren't the usual stink bugs.

So Bernhard calls in the experts: She sends the bug to a Cornell, where a curator mans one of the largest insect collections in the world: And he finds a match. It was the same bug found in Harima, Japan, in May 1916: A brown marmorated stink bug.

Before that moment, there had never been a brown marmorated stink bug officially identified detected on our shores.

But it wouldn't be the last.


Today, there are so many stink bugs reports flooding in that Michael Bush, an entomology and pest management researcher at the Washington State University Extension - Yakima County,  can't keep track of them all.

"I kind of got overwhelmed," Bush says. "I’m sitting here, trying to wade through about 300 reports I’ve gotten since last month. That's probably two-thirds of what we’ve gotten in the last six years."
click to enlarge Invasion! Washington state under siege from the stink bug menace!
Starship Troopers GIF
The battle to defeat the stink bug could be brutal.

Some of that may be simply a result of increased media attention to the stink bug problem. But it's also evidence of just how far the pesky pest has spread.

"The closest find of brown marmorated stink bug a few years ago was in Portland, in Oregon," Bush says. "The first one found in Washington state was in [bordering] Clark County."

Stink bugs can fly, yes. But even more importantly, they can hitch a ride.

"These stink bugs are amazing hitch-hikers," Bush says. "They are attracted by warmth. They will get into cars and SUVs and RVs, there are some thoughts that that's one of the ways they have spread."

The cold months send even isolated stink bugs scurrying toward warmer areas, where they're likely to meet other stink bugs. Then they create a lot of stink bug babies.

By 2014, the WSU Master Gardeners had put out a poster: "Wanted: Dead or Alive," encouraging those who encountered the brown marmorated stink bug to send information to Bush.

On Feb. 20, 2015, the first brown marmorated stink bug was spotted in Spokane. By that July, a WSU entomologist found an egg mass writhing with 28 newly hatched brown marmorated stink bug nymphs.

"In 2017 we found nearly 30 individual brown marmorated stink bugs in Manito Park and in Riverfront Park,"  Bush says. Stink bugs, he says, love deciduous trees. So they love parks. 

So why are stink bugs a problem? First, there's the obvious.

"These things really earn their name. They stink," Bush says. "When they invade households, people find them creeping in around in their house. When they try to remove them, they stink. They stink in protest."

Injure them? Hurt them? Squish them? They still stink.

The exact nature of the odor is in the nose of the beholder, Bush says.

"I think it smells bad, some people don’t," Bush says. "Some people say it smells like rotten cilantro. Others say it smells like dead grass."

And while Washington's agriculture hasn't been impacted yet, the impact in other states has been concerning. The stink bugs come equipped with big long proboscises they stick into plants to suck up the juices of produce plants like tomatoes, apples, apricots or hazelnuts. In the process, Bush says, the stink bugs also vomit up a little bit of bug juice.

"When they do that, they do cause some deformation if it’s early in the season," Bush says.

The produce can rot inside. They can contaminate the plant, altering the flavor. They can also leave a thin layer of white film underneath the skin of the fruit

"People cut it open, and there’s this little white layer between the skin and the rest of the tomato," Bush says. "People tend not to like that when they see it."

Researchers across the country, including several from WSU, have been funded by a U.S. Department of Agriculture grant to research the problem, trying to figure out exactly how to stop the spread of the stink bugs.

So they're looking at pheromone-based traps. But one even cooler idea they're looking at? Basically, a miniature Kaiju battle, introducing another bug that can battle the stink bug. The samurai wasp, an exotic parasitic wasp out of Asia, lays eggs inside the stink bug eggs, which then devours the stink bug progeny from the inside.


The battle is already happening. A samurai wasp has already been detected in Walla Walla, Washington.

And if you see any brown marmorated stink bugs? Don't send the bugs to Bush. He's already overwhelmed. Instead, email They have graduate students tasked with dealing with this sort of thing.

click to enlarge Invasion! Washington state under siege from the stink bug menace! (3)
Washington State University graphic
Behold the terrifying march of the stink bug through Washington state's counties.

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About The Author

Daniel Walters

A lifelong Spokane native, Daniel Walters is the Inlander's senior investigative reporter. But he also reports on a wide swath of other topics, including business, education, real estate development, land use, and other stories throughout North Idaho and Spokane County.He's reported on deep flaws in the Washington...