Destructive stink bugs taking state by swarm

Brown marmorated stink bug. Note white bands on antennae. Photo courtesy of Steve Dilley.
Brown marmorated stink bug found in Olympia. Photo courtesy of Steve Dilley , who sent photos of the insect to WSU for identification. Note the white bands on antennae.

By Linda Weiford, WSU News

PULLMAN, Wash. – Brown marmorated stink bugs creeping across floors, clinging to curtain folds, perching atop countertops. One even flew out of a hair blower.

Since mid-March, Washington State University researchers have been scrambling to keep up with a surge of inquiries from concerned property owners.

“In three weeks, we received 300 emails and phone calls – mostly from the state’s west side,” said WSU entomologist Michael Bush of WSU’s Yakima County Extension. “We’ve never seen so much activity related to this bug — and so quickly.”

The majority of stink bug sightings are in in King, Pierce and Thurston counties, with sporadic reports coming from areas east of the Cascades, he said.

Responding to the high volume of queries, WSU has established a central email address for ‘citizen scientists’ to submit sighting reports. (See below)

“The bugs have used people’s homes to overwinter. Now that temperatures are warming up, they’re trying to make their way back outside,” Bush explained, noting that the jump in activity is worrisome to researchers and farmers alike because brown marmorated stink bugs feed on so many plant species.

Threat to agriculture

Native to Asia, marmorated stink bugs don’t bite, sting or bore into wood, which is why, indoors, they’re considered nuisance pests. Outdoors, they pose a major threat, gorging on vegetables, fruit trees, nuts and ornamental plants. The bugs emit a trademark odor resembling smelly socks when threatened or squashed.

Brown marmorated stink bug found in Olympia on March 25 and photographed by Steve Dilley in his garage.
Note the white bands on antennae. of brown marmorated stink bugs.

They inflicted millions of dollars in damage to agricultural crops in the Mid-Atlantic states in 2010, the same year they were first detected in Washington state. Since then, they’ve taken up residence in 21 counties, ranging from Spokane and Whitman on the east side to Kitsap, King and Clark on the west side.

WSU is one of 18 universities across the nation whose scientists are monitoring the insect’s spread and compiling data with an eye toward containing it.

“The more we learn about this stink bug species, the more amazed we are by its generalist feeding habits,” said WSU extension entomologist Elizabeth Beers, a member of a national scientist SWAT team. “Naturally, our aim is to keep them from damaging Washington’s crops and orchards,” she said.

Fight the invasion

Keep reporting sightings of brown marmorated stink bugs, Beers urged. First, distinguish it from other stinkbug species by thin white bands on their antennae.

Once identified as the brown marmorated variety, snap a photograph with your smartphone to include in an email. Then type your name, the date you found the stink bug, how many, and where — address or city. Then send to:

For property that’s heavily infested – meaning more than 50 – “if we can, we would love to come get your bugs for our research,” said Beers, who will dispatch entomology graduate students to pick them up.


Map highlighting the spreading infestation of the brown marmorated stink bug in Washington state between 2012 and 2017.
The brown marmorated stink bug went from inhabiting one Washington county to 21 counties in just five years. (Courtesy, WSU Tree Fruit Research & Extension)

Media contacts:

  • Elizabeth Beers, WSU entomologist, Wenatchee, 509-679-1010,
  • Michael Bush, WSU entomologist, Yakima, (509) 574-1600,

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