In May of 2020, murder hornets first came on our radar when they were found in the Pacific Northwest. Social media took a hold of the story and made it sound like the next apocalyptic event. However, since then we found out the murder hornets were actually more detrimental to bees than to humans. This past weekend. Washington State Department of Agriculture entomologists successfully eradicated the first Asian giant hornet nest in the United States by vacuuming the hornets out of the nest Saturday, just two days after finding the nest in a tree on private property in Blaine, Washington.
In all, the entomologists with WSDA’s Pest Program removed 98 worker hornets. During the early morning extraction, 85 hornets were vacuumed out of the nest and collected, and another 13 live hornets were collected with a net while observing the nest on Friday.
“The eradication went very smoothly, even though our original plan had to be adapted due to the fact that the nest was in a tree, rather than the ground,” managing entomologist Sven Spichiger said. “While this is certainly a morale boost, this is only the start of our work to hopefully prevent the Asian giant hornet from gaining a foothold in the Pacific Northwest. We suspect there may be more nests in Whatcom County.”
Asian giant hornets, an invasive pest not native to the U.S., are the world’s largest hornet and a predator of honey bees and other insects. A small group of Asian giant hornets can kill an entire honey bee hive in a matter of hours.
Saturday’s operation began at about 5:30 a.m. with the team donning protective suits and setting up scaffolding around the tree so they could reach the opening of the nest, which was about ten feet high. The team stuffed dense foam padding into a crevice above and below the nest entrance and wrapped the tree with cellophane, leaving just a single opening. This is where the team inserted a vacuum hose to remove the hornets from the nest.
The work proceeded slowly at first, with very few hornets emerging. The team members used a wooden board and some smart whacks against the tree to encourage more hornets to leave the nest. This proved successful. When the hornets stopped coming out of the nest, the team pumped carbon dioxide into the tree to kill or anaesthetize any remaining hornets. They then sealed the tree with spray foam, wrapped it again with cellophane, and finally placed traps nearby to catch any potential survivors or hornets who may have been away during the operation and return to the tree. The work was completed by 9 a.m.
“We congratulate the Washington State Department of Agriculture for eradicating this nest,” said Osama El-Lissy, Deputy Administrator of the U.S. Department of Agriculture’s Plant Protection and Quarantine program. “Thanks to their expertise and innovation, this nest is no longer a threat to honey bees in the area. We are also pleased that the radio tags we provided worked so well, allowing state entomologists to tag and track a live Asian giant hornet back to the nest. It’s a strong example of our close cooperation in combatting this pest.”
In the coming week, the WSDA Pest Program intends to cut the tree down and open it to see how big the nest was. The entomologists also want to determine whether the nest had begun to produce new queens or not.
WSDA will continue setting traps through at least November in hopes of catching any more Asian giant hornets still in Whatcom County and potentially locating any other active nests.
The public still has an important role to play in detecting Asian giant hornets in Washington. The nest removed Saturday was found thanks to a report made by a member of the public in September. Every report of an Asian giant hornet leads the agency closer to finding a nest. It remains critical for the public to report every hornet they see each time they see one.
WSDA has been actively searching for Asian giant hornet nests since the first hornets were caught earlier this year. The first confirmed detection of an Asian giant hornet in Washington was made in December 2019 and the first hornet trapped in July of this year. Several more were subsequently caught, all in Whatcom County.
Click here to learn more about Asian giant hornets and Washington’s trapping and eradication project.