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Asian giant hornet bottle trapping and more to continue in 2022

An Asian giant hornet is seen leaving the first nest ever located in the US. (October 22, 2020). Still from a WSDA video

WHATCOM COUNTY, Wash. — Officials with the Washington Department of Agriculture (WSDA) say they will continue trapping and monitoring for the presence of Vespa mandarinia, more commonly referred to as Asian giant hornets (AGH) in Whatcom County this year. These hornets are known to attack and destroy honeybee hives with a few hornets being able to destroy an entire hive in a matter of hours.

Since a nest was discovered and destroyed in Nanaimo, British Columbia in 2019, there have been multiple sightings and captures in northern Whatcom County areas in and around Blaine. Live captures have been equipped with electronic tracking devices and followed to 4 nests located in nearby Alder trees, 1 in 2020 and 3 in 2021.

Confirmed AGH detections to date as of April 20, 2022 (nests indicated in yellow). Source: Washington State Department of Agriculture

WSDA recently posted job opportunities for AGH field trappers in Whatcom County and volunteer citizens continue to be encouraged to participate in the monitoring and trapping.

WSDA’s experimental trapping in the spring for the past 2 years has failed to capture a queen. Instead of trapping this year, citizens are encouraged to participate in a spring queen visual survey from April through May.

This year, WSDA is asking citizens to keep their eyes open and cameras close by in the event an AGH is seen this spring. In that case, citizens are asked to report these sightings and include photographs if safely able to do so.

In the spring, overwintering queens begin to emerge and are known to feed on carbohydrates like tree sap. After they emerge, mated queens will attempt to start a nest. In late May 2020, 1 deceased mated queen was detected in Custer. In June 2020, 1 deceased queen was found flattened in Bellingham. Both deceased queens were reported by citizens.

A new “adopt a wasp nest” program for citizens will begin in June. AGHs have been seen repeatedly attacking paper wasp nests over the past 2 years. WSDA officials are inviting citizens to “Adopt a Wasp” by committing to monitoring paper wasp nests on their property and reporting wasp and hornet activity through October.

Trapping for AGHs begins in July when the worker hornets begin leaving the nests to forage. A call for a citizen bottle trapping effort is expected to occur closer to that time. WSDA officials say, “Traps at this point are likely only to unnecessarily kill native insects with only a very remote possibility of trapping a queen.”

Over 700 hanging bottle traps are being prepared by WSDA to be used to detect worker AGHs as they forage. If a trap is confirmed to have captured an AGH, more traps will be placed in the immediate surrounding area in the hopes of trapping more in an effort to locate their nest.

In the past, WSDA has received reports of suspected Asian giant hornets visiting hummingbird feeders. The hornets are about a third to a half as long as a hummingbird. Anyone who suspects seeing an AGH at a feeder is asked to report it and, if safely able to do so, take a photo or video to be included in the report.

WSDA will have a booth at the annual Whatcom Farm Expo Saturday, April 23rd, from 9am to 2pm to provide more information about their AGH response and citizen opportunities to assist. A presentation is scheduled at 10:30am.

Washington Invasive Species Council AGH presentation (March 11, 2022)

AGH Timeline

  • September 2019, a colony of AGHs is found and destroyed by beekeepers in Nanaimo, British Columbia.
  • December 2019, a specimen found in Blaine was sent to WSDA and confirmed to be an AGH. Report of that finding resulted in learning about 2 previously unreported sightings in September in Blaine.
  • April 2020, WSDA issue trapping instructions for citizens who were interested trapping for AGHs and reporting the results
  • May 2020, WSDA confirmed an AGH queen sighting in Custer
  • June 2020, WSDA begins placing their own bottle traps in areas of previous confirmed sightings
  • June 2020, WSDA confirms an AGH queen sighting in Bellingham
  • July 14, 2020, a confirmed AGH unmated queen found in a Birch Bay area bottle trap
  • July 29, 2020, a confirmed AGH male found in WSDA bottle trap
  • August 19, 2020, a dead worker AGH is found in a beekeeper’s bottle trap
  • September 2020, a citizen reported and photographed confirmed AGHs sightings
  • September 2020, an AGH flew by and was captured with a net by WSDA staff visiting the property of the previous sightings – an unsuccessful tracking attempt followed
  • October 5, 2020, a citizen captured a live AGH – it was lost when released with a tracking device
  • October 22, 2020, 2 more live hornets found by WSDA in a trap – a successful tracking attempt led to an area where AGHs were spotted flying and soon after seen entering a nest in an Alder tree through an opening in the trunk
  • October 24, 2020, WSDA eradicate the nest located in the Alder tree – nearly 100 specimens collected
  • August 19, 2021, a live AGH was captured – a successful tracking effort led to a nest in an Alder tree
  • August 25, 2021, WSDA eradicate the nest located in the tree – 1474 total specimens, including larvae, were collected
  • September 8, 2021, a live AGH was captured – a successful tracking effort led to a nest in an Alder tree the next day
  • September 10, 2021, a live AGH was captured – a successful tracking effort led to a nest high in an Alder tree trunk the next day
  • September 11, 2021, WSDA eradicate the nest located on September 8th – 449 total specimens, including larvae, were collected
  • September 23, 2021, WSDA eradicate the nest located on September 10th – 777 total specimens, including larvae, were collected
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