The insect commonly known as the “Murder Hornet” is scientifically identified as Vespa mandarinia, one of the world’s largest hornet species. This invasive insect captured international attention due to its size and predatory habits. This article provides an update on the official assessment of the threat and the efforts that determined its current status in North America.
Arrival and Initial Discovery
The first confirmed detection of Vespa mandarinia in North America occurred in August 2019 on Vancouver Island in Nanaimo, British Columbia, Canada. Shortly thereafter, a dead specimen was found in December 2019 near Blaine, Washington, marking the initial US sighting. DNA evidence later determined these two separate introductions originated from different maternal lineages.
The species immediately concerned agricultural agencies and beekeepers because of its predatory nature toward European honeybees (Apis mellifera). A small group of these hornets can enter a honeybee colony and quickly slaughter thousands of adult bees, a process that can take as little as 90 minutes. This behavior, known as the “slaughter phase,” allows the hornets to occupy the hive and harvest protein-rich honeybee larvae and pupae to feed their developing young.
Tracking and Eradication Methods
Government agencies in both the US and Canada initiated coordinated, multi-year campaigns to locate and eliminate the invasive population. The first step involved establishing a vast trapping network, primarily relying on citizen scientists and public reports for initial detection data. Traps, often simple bottle traps baited with an attractant mixture like orange juice and rice cooking wine, were deployed across the affected areas.
Once live hornets were captured, teams employed radio telemetry to find the nests. Entomologists affixed tiny radio transmitters, or tags, to the bodies of captured live hornets. The hornets were then released and tracked using a directional antenna and receiver, allowing crews to follow the insects back to their underground or arboreal nest.
This tracking strategy led to the successful discovery of four nests in Washington State’s Whatcom County between 2020 and 2021. These nests were found inside the cavities of red alder trees, demonstrating the cryptic nesting habits of the species. The nests were then eliminated by vacuuming the hornets out and sealing the tree cavity to prevent any remaining individuals from escaping.
Official Status of the Threat
Following the removal of the four confirmed nests, intensive surveillance continued for three consecutive years without any further positive detections. The last confirmed nest was destroyed in September 2021, and no additional hornets were found in 2022, 2023, or 2024. The Washington State Department of Agriculture (WSDA) and the United States Department of Agriculture (USDA) formally declared the northern giant hornet eradicated from the United States in December 2024.
This declaration is based on the scientific consensus that eradication efforts successfully removed the incipient breeding population before it could establish a foothold. The criteria for declaring eradication of an invasive species require a minimum of two to three years of intensive monitoring with zero confirmed sightings. This extended period confirms that no new queens successfully overwintered and started new colonies, preventing the establishment of an invasive presence in the region.
Maintaining Vigilance Against Reintroduction
Despite the success of the eradication campaign, surveillance efforts cannot be abandoned due to the ongoing risk of reintroduction. The pathways by which Vespa mandarinia arrived initially, likely through international cargo shipping, remain active and present a constant threat. A single fertilized queen arriving undetected could restart the cycle of invasion.
Specialized trapping programs are maintained by agricultural agencies as a precautionary measure to detect any new arrivals as early as possible. Public involvement remains a safeguard, with agencies continuing to rely on community members to report suspicious sightings. This sustained vigilance, characterized by a low-level, long-term monitoring strategy, is necessary to protect North American ecosystems.