Vespa mandarinia
Several invasive hornets, including the Northern giant hornet (NGH), have been intercepted in ports throughout the Pacific Northwest. In 2019, NGH was confirmed in and eradicated from British Columbia, Canada. In December 2019, WSDA responded to a public sighting and captured this hornet near the border of Washington and British Columbia. During the 2020 season, citizen scientists, together with WSDA/WSU staff, placed over 2,500 hornet traps in northwestern Washington. In October of 2020, these traps helped WSDA locate and destroy the first NGH nest in the United States. Three additional nests were located and eliminated in 2021. WSDA continues to investigate any reports of the Northern giant hornet in Washington. No detection or confirmed reports of NGH occurred in Washington in 2022 or 2023. The pest will be considered eradicated if there are no confirmed detections in 2024.
Description and damage This hornet resembles our native yellowjacket wasps, but adults can be nearly 2 inches long. Adults have a distinctly yellow-orange head with prominent black eyes, black thorax and black/yellow striped abdomen. This hornet preys on other insects, gathers tree sap, and raids the colonies of other bees and wasps for protein spoils. In late summer and throughout autumn, this hornet will invade honey bee colonies and hives, decapitate bee workers and then feed on the colony brood and provisions. These hornets can sting humans and animals, but only when their nests are disturbed. If you suspect that you have a colony, do NOT attempt to remove or eradicate it. NGH will aggressively defend its own nest. Furthermore, this species of hornet will sting in self-defense, so do not handle any live specimen! The sting of NGH is more dangerous than that of other stinging insects in Washington since it can sting multiple times and deliver a larger dose of venom. Seek medical attention immediately if stung multiple times.
Biology and life cycle In its native range, this hornet nests and forms colonies often in underground chambers early in the spring. In Washington, all of the nests detected were inside of the voids of alder trees. During the summer, the nest expands in size and number. Between July to October homeowners are most likely to encounter foraging adults.
Pest monitoring If you suspect you have found a honeybee colony damaged by this species, or suspect you have encountered this large hornet, please report the finding to the State Department of Agriculture or local university Extension office. If safe, attempt to photograph the specimen and note what direction the hornet flies when it leaves. When confirmed as an invasive hornet of concern, these state agencies will respond and work with you to eradicate this pest as soon as possible.
For further information:
McGann, C. 2019. Pest Alert: Asian giant hornet. WA State Department of Agriculture Ag Briefs. https://wastatedeptag.blogspot.com/2019/12/pest-alert-asian-giant-hornet...