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Find stink bug eggs? B.C. scientists want to hear from you

The province is trying to understand the impact a parasitoid is having on the crop pest population.

Brown marmorated stink bugs (BMSB) have had a foothold in regions in B.C. since 2015 with no signs of leaving. Now, scientists hope people will report only egg sightings to them.

Tracy Hueppelsheuser is an entomologist with the Ministry of Agriculture and Food and explains how the stink bug was first detected in Chilliwack and Kitsilano.

“The bug is here to stay,” she says. 

Stink bugs can cause damage to crops. If you find them in your home, it's not their intended location. 

“Even if you see them walking around your house, they're not really feeding. They're not that active there,” Hueppelsheuser says. 

As temperatures warm up, stink bugs want to go outside and lay eggs on foliage. 

“We were kind of anticipating that the populations would gradually increase, and that's sort of where we are on that timeline,” she says. 

In 2022, the warm fall resulted in a large uptick in stink bug sightings in the Fraser Valley, Vancouver Island and the Interior.

Stink bugs are known to lay eggs by late June to August. The eggs will grow into nymphs and then become adults. 

Province wants you to report stink bug egg sightings

The ministry does have a project on right now looking for stink bug eggs, including ones that have been impacted by a parasite.

“What I'm interested in is if you find stink bug eggs,” says Hueppelsheuser. “We're trying to get an understanding of how widespread the parasitoid is.”

The public should be on the lookout for egg masses; if they turn black, that means parasites are in them. The parasites lay eggs in the eggs of stink bugs, she explains. 

“It's like an invasion of the body snatchers,” she says. “It kills the stink bug embryo and emerges as a new parasite.”

This results in some of the stink bug population being killed, but it isn’t taking the population down to a rate that the scientists want to see. 

Hueppelsheuser notes the stink bug eggs are normally pale green or white in colour and are found on the underside of leaves. 

“People will be looking for about 28 eggs for brown marmorated stink bugs and they’re tiny globes, about a millimetres in size,” she says. 

Should I report stink bug sightings?

People who see stink bugs in the Fraser Valley, Metro Vancouver, Vancouver Island and the Okanagan do not need to report stink bug sightings. 

“We already know that those zones have lots of stink bugs, we don't need to report it,” Hueppelsheuser tells Glacier Media. 

However, provincial officials are interested in hearing about stink bugs in other regions of B.C.

"Say you were from Revelstoke, or Kamloops or Dawson Creek and you happen to see something you thought was a brown marmorated stink bug. I would be interested in hearing about that," she says. 

How to get rid of stink bugs

If stink bugs are found inside a home, there are a few ways to dispose of them. 

Hueppelsheuser explains how one way to kill the crop pest is to put it in the freezer. After a couple of days it'll die.

“You can drown them in a bucket of soapy water if you want to,” she says, adding it will be difficult to kill all of them.

It's also OK to leave them alone.

“If I find them outside, I don't do anything about it now. There's just too many of them,” she says. 

She expects stink bugs to gradually increase every year, but it’s difficult to predict what 2024 will bring. 

“As far as forecasting, that’s a difficult one,” she says, noting 2023 was "bad" for stink bugs. “I would encourage people to just keep an eye out there.”

Stink bugs will feed on peppers, tomatoes, corn, beans, peas, apples and pears. Sometimes they’ve also been known to damage flowers (they're not a danger to people or pets).

“They can be a challenge, certainly if you’re trying to grow food or ornamentals in your garden.” 

How can I tell it's a stink bug? 

A distinguishing feature of a stink bug is its shield-shaped body. 

In 2023, a new stink bug was reported in B.C.’s Interior called the conchuela stink bug.

The bug has a distinct orange border around its body. 

“These groups of bugs were desiccating things like grapes or Oregon grapes, so Mahonia native fruit, and just sucking the juices right out of them and shrivelling them up,” Hueppelsheuser says. 

Reports from the Kootenays, Okanagan and Pemberton came into the ministry about the bugs. 

Sightings can be reported online via the B.C. government's website.

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