Asian Giant Hornet

Close-up photo of Asian giant hornet, Vespa mandarinia. Photo by Karla Salp Washington State Department of Agriculture.

Producers wonder if the so-called “murder hornet” could injure themselves – or their ability to grow crops.

“Protecting honeybees and other native bee species is important for agriculture, including crop and forage production,” said Janet Knodel, North Dakota State University professor and Extension entomologist.

The bee industry and entomologists across the U.S. and Canada are asking producers and beekeepers to keep an eye out for the hornet, known as the Asian giant hornet.

“The Asian giant hornet is the world’s largest hornet, with females attaining lengths of nearly 2.5 inches,” Knodel said. It has distinctive markings, with a large orange or yellow head and black and orange stripes across its body.

The Asian giant hornet kills honeybees and feeds bee pupae and larvae to its young. However, the giant hornet feeds on other insects, as well.

“It takes only a few Asian giant hornets a few hours to kill adult bees and take over a bee colony,” she said.

The hornet is native to Asia, and in 2019, nests were found near Vancouver, Canada.

In the state of Washington, there were two verified reports of the Asian giant hornets in Blaine, Wash., in December 2019.

According to the ARS, a single Asian giant hornet specimen was found and verified in May 2020 near Custer, Wash.

Even in Asia, human deaths from the giant hornet are rare, and usually result from an allergic reaction.

“We want the Asian giant hornet out of the U.S. Any invasive species of insects are dangerous to our own insects, especially beneficial insects and pollinators,” Knodel said.

With honeybees, research has shown there is a crop yield benefit from bee hives being in the area.

“Producers like to use bees for the pollination of some crops,” she said. “You don’t always see a yield benefit from some self-pollination crops. Yet, even with oilseed canola, which is self-pollinating, producers have seen a yield benefit of up to 13 percent when bees are in the area, compared to those areas without bees.”

In Washington State, ARS scientists are working to trap and eliminate the Asian giant hornet.

Jacqueline Serrano, insect chemical ecologist with the ARS Temperate Tree Fruit and Vegetable Research Unit in Wapato, Wash., said the Asian giant hornet is especially dangerous in late summer because of the way it hunts down honey bees and other insects for protein to feed its young.

ARS has put out traps in Washington with lures that were developed with the Washington State Department of Agriculture.

“If the Asian giant hornet were to become established in Washington State, it could pose a serious threat to the beekeeping industry,” Serrano said.

Serrano is leading efforts to develop attractants for use as bait in Asian giant hornet traps in Washington.

“There are many different aspects of the Asian giant hornet’s chemical ecology, including feeding attractants and pheromones, that can be used to develop attractive lures,” Serrano said.

If her traps collect more specimens, ARS scientist will use those specimens to conduct genomic sequencing as part of the ARS Ag100Pest Initiative.

According to ARS, the Ag100Pest Initiative “focuses on deciphering the genomes of 100 insect species that are most destructive to crops and livestock and are projected to have serious bioeconomic impacts to agriculture and the environment.”

Hopefully, the giant hornet will never be spotted outside Washington, but the bee industry wants everyone involved in agriculture to be on the lookout.

Knodel recommends calling a local Extension agent if someone comes across any hornet that looks like it may be the Asian giant hornet and/or its nest.