State nets its first Asian giant hornet

By Robert Whale • August 7, 2020 5:30 am
Asian giant hornet (Vespa mandarinia) is the world’s largest species of hornet. Courtesy of WSDA
Asian giant hornet (Vespa mandarinia) is the world’s largest species of hornet. Courtesy of WSDA

The Washington State Department of Agriculture (WSDA) has trapped its first Asian giant hornet.

According to WSDA’s website, trappers found the hornet in one of the state agency’s bottle traps set near Birch Bay in Whatcom County on July 14, and submitted the contents for processing at WSDA’s entomology lab.

Entomologists identified the hornet during processing on July 29, making it the first murder hornet to be detected in a trap, rather than found in the environment as were the state’s five previous confirmed sightings.

“This is encouraging because it means we know that the traps work,” said Sven Spichiger, managing entomologist for the department. “But it also means we have work to do.”

WSDA’s next steps are to search for nests using infrared cameras and to place additional traps to catch live Asian giant hornet specimens. WSDA Pest Program staff will deploy special traps to trap hornets, but keep them alive. If they catch live hornets, the department will tag and track them back to their colony. Once located, the agency will eradicate the colony.

WSDA hopes to find and destroy the nest by mid-September before the colony begins creating new reproducing queens and drones. Until that time, the colony will only contain the queen and worker Asian giant hornets. Destroying the nest before new queens emerge and mate will prevent the spread of this invasive pest.

In addition to the traps that WSDA has set to catch Asian giant hornets, citizen scientists and other cooperators have placed more than 1,300 traps. Those interested in trapping can still build and set traps on their own property. Traps require weekly bait replacement and a commitment to mail the trap contents to WSDA if bees or wasps are collected. If a citizen scientist traps a live Asian giant hornet, they should call the WSDA Pest Program hotline at 800-443-6684.

Because the number of Asian giant hornet workers increases as a colony develops, residents should be most likely to see an Asian giant hornet in August and September. Anyone who thinks they’ve seen one should report it at agr.wa.gov/hornets. providing as much detail as possible about they saw and heard. Also, include a photo if you can safely obtain one, and if you come across a dead specimen, keep it for potential testing.