The Asian giant hornet has invaded the Pacific Northwest. It is a threat to honey bees, the honey industry, and people.

The bald-faced hornet (left) is the largest hornet in North Dakota, but much smaller than an Asian giant hornet (right).

A honeybee (HB) and bumble bee (BB) are much smaller than an Asian giant hornet (AGH). The Eastern cicada killer (ECK) is of comparable size but is not aggressive toward bees or humans.

Hornet populations explode this time of year.  

This includes the populations of the Asian giant hornet, a vicious pest that invaded Washington State in 2019. Scientists and citizens in Washington are currently monitoring over 1,400 traps to exterminate the new pest.  

These persons are concerned because Asian giant hornets (AGH) (Vespa mandarinia) are ferocious bee killers. AGH may swarm and capture a beehive in hours. First, the hornets slaughter and decapitate the adult bees. Then they feed the honey bee brood to their own young hornets. This ruthless behavior has given AGH the nickname of the “Murder Hornet.”

Asian giant hornets are massive compared to the bees and hornets in North Dakota. AGH are the biggest hornets on earth; the females reach about 2 inches in length. Wow!

Our honey bees are defenseless. Their stingers cannot penetrate the “armor” of these huge hornets.

Because of their large size, AGH can deliver more venom than other hornets. When threatened, they will aggressively defend their colony and can sting repeatedly. Beekeepers may be at risk since the stingers of AGH can penetrate through some beekeeper suits, delivering nearly seven times the amount of venom as a honey bee.

North Dakota is the #1 state in honey production. Asian giant hornets may become a threat to us and our honey industry in the future. As of today, we have very little to worry about.

 AGH has not been detected outside of the Pacific Northwest. Its populations have been very low and vigorous efforts are being made to destroy all nests.

AGH will not sting humans unless it feels threatened and has not attacked any humans in North America to date. 

Thank goodness for our bitter cold winters! It will be very hard for these foreign hornets to survive and become established here.

In case you see a giant wasp in North Dakota, it is most likely an Eastern cicada killer. It is comparable in size, but not aggressive. This “gentle giant” is a solitary wasp that makes holes in the ground. The females will kill cicadas and place them in the holes to feed their young.

Written by Tom Kalb, Extension Horticulturist, NDSU. 

Sources:

Beauzay, P. and J. Knodel. 2020. Facts about the Asian giant hornet. NDSU Crop & Pest Report. May 14, 2020.

Pliesch. 2020. 6 things to know about the Asian giant hornet. University of Wisconsin, Madison.

Washington State Department of Agriculture. Invasive hornets. https://agr.wa.gov/departments/insects-pests-and-weeds/insects/hornets. Accessed August 18, 2020.

Photos were made available under Creative Commons licenses specified by the photographers: Washington State Department of Agriculture, Bugwood.org; Washington State Department of Agriculture; Hanna Royals, Museum Collections: Hymenoptera, USDA APHIS PPQ, Bugwood.org.