State agriculture officials will put up about 1,500 traps this year in a continuing effort to find and destroy invasive Asian giant hornets, with a primary focus on northern Whatcom County.
That's where the first nest discovered in Washington state — discovered in the cavity of a tree southeast of Blaine — was found and destroyed on Oct. 24. It was also the first nest found in the U.S.
As they gear up for another trapping season, officials are again asking for the public's help with two tasks:
— Keep your eyes open for what are popularly known as "murder hornets" and report sightings to the Washington State Department of Agriculture.
Overwintering queens will emerge in spring, starting in March, and start trying to create new nests soon after. Nests usually last a year, with males and workers dying in winter.
Last year, there were 31 confirmed sightings of Asian giant hornets in Whatcom County. Those sightings also were the first for Washington state and the U.S.
Sixteen of them came through reports from the public, officials said during a virtual media briefing on Wednesday, March 17, about the 2021 surveillance season.
"We had so much help from everybody," said Sven Spichiger, an entomologist with the Washington State Department of Agriculture.
So far, there have been no reported sightings of Asian giant hornets in Whatcom County in 2021.
— They're also calling on citizen scientists to hang up their own traps starting in July, especially those living in Whatcom, Skagit, San Juan, Island, Jefferson and Clallam counties.
In 2020, more than 1,200 people hung up traps and serviced them, helping agriculture officials with their surveillance and trapping efforts, Spichiger said.
Those were among the briefing's topics, which included discussions about surveillance and trapping plans this year for Washington state and British Columbia, which found and destroyed an Asian giant hornet nest in Nanaimo on Vancouver Island in 2019.
None were reported on Vancouver Island last year, officials said, and the area could be declared Asian giant hornet-free if none are reported in 2021.
On Wednesday, officials on both sides of the U.S.-Canada border also talked about cross-border collaboration and sharing of information.
"It is not just a British Columbia problem or a Washington state problem. It is a collective problem that we are trying to address," said Paul van Westendorp, of the British Columbia Ministry of Agriculture, Food and Fisheries.
As for the public's help, van Westendorp said that six Asian giant hornets were collected in British Columbia last year, specifically in the Fraser Valley.
None were found in traps set by B.C. government scientists, he said. All were reported by the public.
As for trapping efforts in Washington, state scientists will continue to use orange juice and rice cooking wine in their bottle traps.
Citizen scientists can continue to use that concoction this year, or switch to a bait made of one cup water to one cup of brown sugar, according to Spichiger.
The brown-sugar bait is cheaper and has the added benefit of allowing people to service their traps every two weeks instead of every week, Spichiger added.
What's at stake
Since 2019, the Washington State Department of Agriculture has been leading the push to find and destroy the invasive hornets so they don't become established. Those efforts have focused on Whatcom County.
"This is not a species we want to tolerate here in the U.S. and certainly not in Washington State," Spichiger said.
All of the hornets that have been found in the state so far have been found in Whatcom County.
Up to 2 inches long, the Asian giant hornet, or Vespa mandarinia, is the world's largest hornet species. They are identifiable by their large yellow/orange heads.
The hornets are known for their painful stings. They will attack people and pets when threatened. People should be extremely cautious near them, state agriculture officials have said, and those who have allergic reactions to bee or wasp stings should never approach an Asian giant hornet.
The hornets' native range is Asia. They also are known as the Japanese hornet, yak-killer hornet and the giant sparrow bee.
In North America, Asian giant hornets are feared for the threat they pose to honeybees and, by extension, the valuable crops in Washington state that the bees pollinate, including blueberry and other cane crops in the region that includes Whatcom County.
They also prey on local pollinators such as wasps, posing a threat to the local ecosystem.
When Asian giant hornets are in their slaughter phase, which they enter in the fall, they mark a honeybee hive, attack it, use their powerful jaws to decapitate the bees, and take the bees' young to feed their own. A few hornets can kill 30,000 honeybees and take out a hive within hours, and managed honeybees here have no defense against them because the hornets are an invasive species that the bees haven't had a chance to evolve with.
The hornets usually nest in the ground, although the nest found and destroyed near Blaine was in the cavity of an alder tree.
That nest was considered small and it contained 200 virgin queens, Spichiger said during the briefing on Wednesday.
It's not known exactly how the Asian giant hornet found its way to Whatcom County, but officials have said they suspect that an overwintering queen or queens hitched a ride in ballast or commodities on traffic between Asia and North America.
Report hornets
Washington state residents can report possible sightings of an Asian giant hornet to the state Department of Agriculture online at agr.wa.gov/hornets, via email at hornets@agr.wa.gov, or by calling 1-800-443-6684.
British Columbia residents can report to the Invasive Species Council of B.C. at 1-888-933-3722, online at bcinvasives.ca/report, or via the council's "Report Invasives" mobile phone app.
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