The emergence of the so-called “Murder Hornet” (Vespa mandarinia) in North America captured widespread media attention starting in late 2019. This invasive insect is the world’s largest hornet, with queens reaching nearly two inches in length. Originating from Asia, its discovery in the Pacific Northwest generated alarm due to its predatory nature toward honeybees. Public concern centered on the threat this large insect posed to human safety and agricultural stability. This report details the scientific response and provides a status update on the species in the United States.
The Initial Invasion and Alarm
The species was first confirmed in North America in August 2019 in British Columbia, Canada, followed by a finding in December 2019 in Washington State, near Blaine. The hornet earned its nickname due to its effective method of attacking European honeybee colonies. A small group of these hornets can enter a “slaughter phase,” systematically decapitating thousands of adult honeybees in a matter of hours. This predatory behavior allows them to harvest the bee brood (larvae and pupae) to feed their own developing young, threatening the beekeeping industry and agricultural pollination services. The official common name, Northern Giant Hornet, was later adopted by the Entomological Society of America.
The Scientific Eradication Strategy
The Washington State Department of Agriculture (WSDA) and the U.S. Department of Agriculture (USDA) spearheaded the multi-agency response. The initial strategy used extensive public and agency trapping to confirm the hornet’s range in Whatcom County, Washington. Specialized bottle traps baited with orange juice and rice wine captured foraging workers.
Finding the nests, often hidden in subterranean cavities or tree hollows, required a sophisticated approach. Entomologists utilized fine silk thread to tether miniature radio-frequency identification (RFID) tags to captured hornets. This technique allowed tracking teams, using specialized radio telemetry equipment, to follow the insects back to their colonies. This was the most effective way to pinpoint nest locations.
Between 2020 and 2021, this tracking led to the discovery and eradication of four nests. Nests were found in various locations, including a dead alder tree and cavities up to 15 feet high in living trees. Specialized teams wearing heavy-duty protective suits conducted the physical eradication, often vacuuming the hornets out of the cavity before sealing the entrance.
Current Status and Monitoring Efforts
The aggressive strategy proved effective, resulting in a major milestone for invasive species management. Following three consecutive years without confirmed detections, the WSDA and USDA jointly declared the Northern Giant Hornet eradicated from the United States in late 2024. The last confirmed nest was destroyed in September 2021, and no specimens were found during the trapping seasons of 2022, 2023, and 2024. This success was achieved through advanced scientific tracking and considerable assistance from citizen scientists who reported sightings and maintained traps.
Surveillance and monitoring efforts remain in place to prevent the species from re-establishing. The trapping program continues annually, particularly in Whatcom County, to ensure early detection should a queen arrive and found a new colony. Ongoing monitoring focuses on prevention, recognizing that invasive species can be reintroduced through international trade. The public is encouraged to report any sightings of large, unusual hornets to the state agricultural department.