On December 8, 2019, a Blaine, Washington resident reported finding a large, dead hornet on his property. The Washington State Department of Agriculture (WSDA) identified this specimen as Vespa mandarinia, the Asian giant hornet, and the National Identification Services (NIS) confirmed the identification. The Washington detection followed the eradication of a V. mandarinia nest in Nanaimo on Vancouver Island, British Columbia, Canada on September 18, 2019. These were the first detections of the Asian giant hornet in North America. Beekeepers have reported other observations dating back to October through public outreach campaigns by Washington State and British Columbia.
Vespa mandarinia Smith (Hymenoptera: Vespidae), the Asian giant hornet, is the world’s largest hornet and is a social insect native to Asia. The hornet is a pest of Apis mellifera L., the European honey bee, and causes losses to beekeepers in its native range. Vespa mandarinia is a social insect, with a large colony containing one queen and many workers.
Vespa mandarinia is a large hornet that is primarily a pest of honey bees.
Population dispersal is restricted to the spread of queens.
Eradication of this species focuses on eliminating queens. Strategies to achieve this vary depending on the time of season. Queens can be directly trapped and killed in the early spring and late fall. During the summer, nests can be located and destroyed.
Nests are formed in the ground and are challenging to locate. Methods for locating nests involve labor intensive strategies.
Some traps and baits for surveying V. mandarinia already exist. Other traps and baits have been used for closely related species. We recommend using traps and baits that have been previously successful for trapping V. mandarinia. However, we anticipate that resource constraints might dictate the best trap and bait combination.
Typical protective clothing worn by beekeepers will not prevent V. mandarinia sting injuries. The material must be much thicker to protect the wearer from V. mandarinia stings.
Beekeepers in the Bellingham area (Whatcom County - ground zero) have begun coordinating with WSDA to distribute traps in a grid pattern they are developing.
For those of you who want to put out traps (which may also work well for our native yellowjackets) the publication "USDA Pest Response Guidelines for Vespa mandarinia” has some diagrams of home-made traps that have been used successfully in Japan to help control the pest. The link to this document is shown below: