Asian giant hornets are entering their “slaughter phase,” and the Washington State Department of Agriculture has set up an emergency phone line for beekeepers to report in-progress attacks on hives.

State entomologist Sven Spichiger asked beekeepers to resist the urge to defend their hives. Instead, beekeepers should watch which direction the hornets go to help find the nest, the key to keeping the world’s largest stinging wasps from colonizing the U.S.

“Our slogan is, ‘Track it, don’t whack it,’” he said Oct. 2.

The agriculture department has documented 15 Asian giant hornets since late last year. All have been found in Whatcom County in northwest Washington. Murderous to bees, they had never previously been seen in the U.S. The hornets also have been found just north in British Columbia.

They’re a threat to agriculture because they swarm hives, decapitating worker bees and feasting on the brood. A recent study by Washington State University entomologists and WSDA entomologist Chris Looney estimates the invasive hornets could reach Oregon in 10 years and Central Washington in 15 years.

To prevent that, the department wants to find and eradicate their nests. The department had its first crack this week at tracking a live Asian giant hornet back to its nest.

Looney netted the hornet Sept. 29 as he talked to a homeowner just east of Blaine, where Asian giant hornets had been stalking paper wasps under the eaves and in the attic of the house.

The tracking effort the next day came apart when glue took too long to dry and a tiny electronic tracking device slid off the hornet. Entomologists tried tying the device to the hornet, but its wing had dipped into the glue, making it unable to fly and unable to lead entomologists to the nest.

The department had practiced gluing devices on another type of hornet, but the Asian giant hornet has less hair for the glue to stick to, Spichiger said.

The department will try to find faster-drying glue and test glues on the cadavers of Asian giant hornets, he said.

The department has set 30 traps in the area to catch another live hornet. Spichiger said he was “supremely confident” of another chance. “We do hope to have this nest located within a couple weeks at the latest,” he said.

Asian giant hornets nest in the ground and in the woods. Trees and brush could complicate tracking one all the way to its nest. “It may be a daunting task to find the exact location,” Spichiger said.

No beekeeper has reported an attack by Asian giant hornets this year. Spichiger said he anticipated hearing reports this month.

“The Asian giant hornet, this time of year, starts going into what we call the ‘slaughter phase,’” he said. “We’re gearing up to let beekeepers know this is the season to be on guard.”

Honey bees are native to Europe. Spichiger said he thought it was significant that the hornets were going after paper wasps, a native species. “We have now confirmed they’re also attacking some of our native pollinators,” he said.

Asian giant hornets like areas that have cool to warm weather, are wet and are inhabited by humans, according to research by Looney and WSU entomologists Gengping Zhu, Javier Gutierrez Illan and David Crowder.

Spichiger thanked the public for reporting hornets. The homeowner east of Blaine caught two hornets, leading to Looney netting the live hornet. In standard traps, the hornet drowns in a mix of orange juice and rice wine used as bait.

Spichiger described the hotline set up for beekeepers as “similar to 911.” To be used, he said, “if they’re experiencing a live hive attack.”

The number is (360) 902-1880.

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