Latest scourge comes with a bad bite

As if the new coronavirus weren’t bad enough, another scourge from Asia is likely to affect some Whatcom County residents this year.

After receiving reports of Asian giant hornets in the areas of Blaine and Bellingham earlier this year, the Washington State Department of Agriculture (WSDA) now plans to track and trap this invasive species from Asia, which was not previously found in Washington state prior to December. WSDA received over 80 calls about Asian giant hornets following the publication of its initial report in December, although most of the sightings could not be positively identified without photographs.

According to WSDA, invasive Asian giant hornets are typically almost an inch and a half long and are distinguished by their large yellow heads. They nest in the ground, and although they are typically not interested in humans, pets or large animals, they can inflict a painful sting if threatened or if their nest is disturbed.

“Asian giant hornets do pose a threat to people because their venom is more toxic and they have more of it,” said WSDA public engagement specialist Karla Salp. “However, they will not generally attack people unless they feel threatened. Your biggest risk is if you were to step into an Asian giant hornet nest.”

In winter, mated and unmated Asian giant hornet queens hibernate in the ground before emerging in the spring, Salp said. When they emerge from hibernation, the queens start feeding on carbs, usually sap from trees including oak trees. They also lay eggs to create their own colonies, which can consist of many hundreds of workers, which look like queens but are smaller in size.

Once the number of workers grows, the workers start foraging for food in the summertime. They eat insects, with honeybees being their favorite type of insect. Last fall, a bee hive near Custer was wiped out, and WSDA experts believe this may have been the work of Asian giant hornets.

WSDA is now collaborating with beekeepers to set traps for the queens that emerge, Salp said. These “sap traps” consist of a sticky board with a mesh covering to protect birds. This summer, WSDA will also set traps for Asian giant hornet workers. These will be carb- or protein-based traps. The workers will be tagged and tracked back to their colonies so that the colonies can be exterminated.

WSDA is also conducting genetic testing of Asian giant hornets to determine if different populations are related or not. There is a possibility that Asian giant hornets were introduced into Washington and B.C. separately, Salp said.

In a March 20 bulletin, the B.C. Ministry of Agriculture urged residents along the U.S./Canada border to report sightings of Asian giant hornets to the Invasive Species Council of B.C. “Wooded habitat, like areas near the Canada-U.S. border, offer suitable hornet nesting grounds,” said the bulletin. “Residents along 0 Avenue may be the first to notice them.”

The bulletin noted that the Asian giant hornet was first found in B.C. in August last year in Nanaimo. The single nest was located and destroyed. In November, a single specimen was found in White Rock. On May 15, another specimen was killed in Langley, B.C.

On this side of the border, the best way to stay informed about Asian giant hornets is to join WSDA’s pest program listserv and its “Asian Giant Hornet Watch” Facebook group. Links to these resources, as well as an online form to report Asian giant hornet sightings, can be found at agr.wa.gov.

If you’d like to be part of the search for the giant hornet, view Bennett Blaustein’s trap-making lesson at bit.ly/3cfXVsJ