Samurai wasps ready to help BC solve its bedbug problem

Brown, smelly bugs caused a hell of a stink in British Columbia

The province’s Invasive Species Council recently issued a warning about stink bugs, which nibble on a wide variety of plants and are also looking to enter your home for the winter.

The number of British Columbians spotting the pests appears to be unusually high, but experts say that doesn’t necessarily mean they are worse this year.

« It’s hard to say this year if it’s worse overall than previous years, » said Paul Abram, a researcher at Agriculture and Agri-Food Canada, explaining that the number of bedbugs in certain cities or regions tends to change from year to year. in year. year.

Stink bugs threaten crops, orchards and vegetable gardens because they eat apples, grapes, peaches, berries, peppers, beans, tomatoes and nuts.

“What we think we’re seeing this fall is that because fall is so unusually warm, the stink bugs are much more active – so people are seeing them more,” Abram said in an interview.

Abram says he and his team at an experimental farm in Agassiz, British Columbia, are working to map the DNA of bedbugs in the province. Their research shows that the local species is more closely related to brown marmorated stink bugs in China than in Japan.

Bedbugs are present in Metro Vancouver, the Fraser Valley, Vancouver Island and the Kelowna area. The working theory is that they traveled with goods shipped from Asia when they started appearing in British Columbia in 2015.

The good news: one of their natural predators also seems to have hitched a ride.

« We first found the wasp [in B.C.] in 2019,” Abrams said, describing the parasitic samurai wasp as a “potential biological control agent” that has been used to control bedbugs in other countries.

Samurai wasps lay their eggs inside stink bug eggs and take about a month to emerge, killing the stink bug embryo. Abrams says it’s possible that when the insects traveled abroad, the wasps went with them.

He and his colleagues are monitoring wasps to see if they are killing enough stink bugs to really reduce their numbers in British Columbia. While he says they haven’t seen many samurai wasps in the year since their first discovery here, the last two years have been more promising.

« In 2021…we’ve seen at times up to 80% of stink bug eggs were killed by the wasp, » he said.

« And we’ve found him in multiple locations this year, including inside Kelowna as well as the Lower Mainland. »

Brown marmorated stink bugs, scientifically known as halyomorpha halys, pose a threat to crops and plants as they like to nibble on apples, peaches, grapes, berries, beans, tomatoes, and different types of nuts. (Warren Wang)

Province asks people to report and kill bedbugs

Katie Marshall, an entomologist and assistant professor in the department of zoology at the University of British Columbia, says if you see a stink bug, you should let the province know.

« The BC Invasive Species Council has asked British Columbians to submit reports if they see them, » she told CBC. The first edition.

Marshall says BC is trying to manage the stink bug population without disrupting other parts of the ecosystem, adding that the insects have caused « millions of dollars in damage » to apple and grape crops.

She also mentioned samurai wasps as an interesting piece of the puzzle and a potential solution. When it comes to destroying the pests people pick up on their plants, Marshall says there are several options.

« You can put them in soapy water and they’ll drown. My favorite method is to put them in the freezer and freeze them, » she said. « But you want to make sure they spend a good 24 hours in there. »

Hope for the future

Abrams says the B.C. Ministry of Agriculture and Agriculture and Agri-Food Canada also reached out to the public for help this summer, asking for volunteers to collect and deliver stink bug eggs.

That project ended at the end of August, but he says he’ll be back next year, as part of an effort to see how widespread the wasps are and gauge the impact they’re having on the BMSB population control.

samurai wasp
A samurai wasp inspects brown marmorated stink bug eggs as she prepares to lay her own eggs inside. British Columbia researchers hope the parasitic wasp can help reduce stink bug populations before the invasive species causes more damage to crops and gardens. (Warren Wang)

While other countries like the United States and Italy have bred and released samurai wasps to deal with major infestations, Abrams says doing this on a scale large enough to make a difference is « extremely expensive » and not possible in British Columbia.

« The hope is that the natural populations of these wasps will spread and sustain themselves and attack enough stink bugs to curb their populations, » he said.

Abrams says it will be some time before he and his colleagues can report definitive results.

« This type of ecological interaction, it often takes years to stabilize, » he said. « It’s going to be at least a few years before we know that. »


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