With winter nearing, Asian giant hornets are flying less and queens will soon hibernate, but there’s still time to find a second nest this year, Washington State Department of Agriculture entomologist Sven Spichiger said Nov. 10.
Traps remain up, and hornets theoretically are in their “slaughter phase” and could still attack bee hives, he said.
The department has destroyed one nest, containing about 500 hornets in various life stages. It suspects there are at least several more nests in northwest Washington. “It’s possible we could find another one this year,” Spichiger said.
The department sucked 85 hornets from a tree cavity Oct. 24 east of Blaine in Whatcom County. It was the first Asian giant hornet nest ever found in North America. A handful of the hornets have been found in British Columbia, but no nests.
“The real epicenter appears to be in your state [Washington],” B.C. provincial agriculturist Paul van Westerndorp told reporters in a video conference. “I do have dark suspicions we have some nests, too.”
At the same video conference, Spichiger described what entomologists found when they split open the tree and examined the nest. The worker hornets vacuumed out were only part of the haul.
In all, the nest had held about 200 queens. Some might have already left the nest, but only a few, Spichiger said. “It seems like we got there in the nick of time.”
The department, aided by the USDA, is out to eradicate Asian giant hornets, the world’s largest stinging wasps. The agencies say an all-out effort is called for because the hornets are murder on pollinators, particularly honey bees.
Since late last year, hornets have been found in a few spots in Whatcom County, all north of Bellingham. They had never been confirmed loose in the U.S. before. One bee hive was destroyed last year, but the department has not received any reports this year of hornets slaughtering bees.
“That is extremely encouraging to us,” Spichiger said. “We don’t expect that it’s over for the year, but feel very fortunate we haven’t experienced one here in 2020 yet.”
Spichiger said it’s possible someone smuggled in hornets to breed as food. He said Facebook friends in Thailand posted photos of fried Asian giant hornet brood. He said it looked tasty, but that few people would want to travel with live hornets.
More likely, a hibernating queen came as a stowaway and entered the country via international commerce, he said. “We’ll never know.”
Spichiger said he expects queens to be able to survive the Northwest winter, even a hard one. Research has found the hornets able to withstand harsh Korean winters.
“In general, they will pick a nest area that’s protecting them from danger, and they’ll get through the winter just fine,” he said.
Westerndorp said the hornets found in B.C. have been just north of the border, with the exception of one found about 10 miles to the north. The province and state will work together next year to eradicate the wasps, he said.
“The whole party will start up again early next spring,” he said.