Friday, August 5, 2022

Pest alert: Have you seen this huge moth? It just showed up in Bellevue

Karla Salp

The non-native atlas moth compared with large
moths found in North America. 
Washington State entomologists are asking the public to report sightings of the atlas moth after one was recently discovered in Bellevue. There are no known traps for atlas moths, so WSDA is hoping to determine whether there are additional moths in the area based on public reports. With this single atlas moth detection only, there is no evidence that an atlas moth population is established in Washington.

Residents are encouraged to photograph, collect, and report atlas moths if they are seen. The moths do not pose a public health threat and thus can safely be photographed, handled, and collected.

“This is a ‘gee-whiz’ type of insect because it is so large,” Sven Spichiger, WSDA managing entomologist, said. “Even if you aren’t on the lookout for insects, this is the type that people get their phones out and take a picture of – they are that striking.”

Washington State residents who believe they have seen this moth should send a photo to for identification and include the location where it was spotted. While there are no reports of atlas moth anywhere else in the U.S., if you believe you’ve found it outside of Washington State, please take a picture of it, note the location, and report it to the State Plant Regulatory Official or State Plant Health Director in your state.

The atlas moth found on a Bellvue garage
The moth was initially reported to WSDA via a University of Washington professor on July 7. WSDA entomologists identified it as an atlas moth and sent it to USDA for confirmation, which is the standard process for new pest detections. USDA’s Animal and Plant Health Investigation Service confirmed the specimen as an atlas moth on July 27 and it is believed to be the first confirmed detection of the moth in the United States.
Atlas moth compared to a man's hand

One of the world’s largest known moths with a wingspan of up to almost 10 inches, it is also a federally quarantined pest – meaning it is illegal to obtain, harbor, rear, or sell live moths whether adults, eggs, larvae, or pupae without a permit from USDA. USDA has more information about permits on its invertebrate pets web page. While there is minimal research about the moth, entomologists believe host plants may include apple and cherry.

“This is normally a tropical moth. We are not sure it could survive here,” Spichiger said. “USDA is gathering available scientific and technical information about this moth and will provide response recommendations, but in the meantime, we hope residents will help us learn if this was a one-off escapee or whether there might indeed be a population in the area.” 

Note: This blog was updated on August 17 to reflect that rather than being the world's largest moth, it is one of the world's largest moths.