Summer is here - time to put your Hornet Hunter hat back on

Karla Salp
Communications

Gov. Inslee dons a hornet hunter hat while 
touring the hornet detection area in 2022. Gov.
Inslee and the Washington Legislature have been
very supportive of the hornet eradication efforts.

July is finally here and you know what that means around WSDA: time to start trapping for hornets! Our hornet trappers are already out in the field setting hornet traps in Whatcom County.

Since the first confirmed detection of the northern giant hornet (Vespa mandarina, also known as the Asian giant hornet) in 2019, there has been overwhelming interest from the public to help eradicate this invasive pest.

WSDA has welcomed this community support, leading to a hybrid government-public response that has been revolutionary – and effective. More than half of the confirmed hornet detections in the state have come from public reports. Three of the four nests eradicated in the state were found as the direct result of public reports.

The community has played a game-changing role in WSDA’s efforts to eradicate the hornets from our state. Although we had no detections last year, we’re not out of the woods yet.

We still need you.

Hornet sighting reported
to WSDA via social media
in 2020.

Your eyes, ears, and traps are still needed to detect any hornets that might still be lurking in the state. Here are three ways that you can help.

1. Trapping. WSDA has established a Public Hornet Trapping project, which provides community members with information on how to build and check hornet traps and report any hornets that are caught. The traps are placed in July and are left up through November.
2. Watch a Wasp Nest. The public and WSDA staff have witnessed northern giant hornets repeatedly attacking paper wasp nests. These nests can easily be found under the eaves of many buildings. By joining the “Watch a Wasp Nest” program, you commit to spending five minutes a week observing paper wasp nests on your property and logging activity, including whether you notice hornets at the nest.
3. Report sightings. Helping detect northern giant hornets can be as simple as being aware of your surroundings. If you think you spot one, get a photo if you safely can. Report suspected sightings with as much detail as possible, including where the insect was spotted, what it was doing, and if it flew off, the direction in which it headed.

EVERY hornet report matters. Whether found while trapping, watching paper wasp nests, or just being observant when you are out and about, it is critical to report each and every suspect hornet sighting. We get hundreds – if not thousands – of false reports each year, but we gladly accept them because it means you are on the lookout and that means we receive the few but critical confirmed detections we need to eradicate the hornets for good. 

Watch a wasp nest to help detect northern giant hornets

Cassie Cichorz
Pest Program

Paper wasp on a nest in Washington State

Did you know you can help protect Washington from invasive species just by taking a walk around your house or barn once a week? 

Over the last few years, residents of Whatcom County and WSDA staff have noticed hornets attacking paper wasp nests. In 2021, WSDA tracked a hornet and observed it repeatedly visiting the same paper wasp nest. Each visit lasted five to ten minutes and the hornet removed paper wasp larvae.  

WSDA invites you to help watch for northern giant hornets (Vespa mandarinia). Join our community science project to locate active paper wasp nests, watch the nests weekly, and record your observations from June through October. WSDA will continue to invite residents to participate in public scientist trapping too.

Northern giant hornet attacking a 
paper wasp nest on a house in Whatcom County

Paper wasps (Polistes dominula) can grow to about three-quarters of an inch long and have a well-defined “wasp waist” that makes them easy to identify. Paper wasps are typically not aggressive and do not readily attack people, but they can sting if threatened. They form small colonies and build hanging, open-comb nests on building eaves, frames, abandoned cars, or branches of trees and shrubs. Paper wasp nests vary in size and are usually gray to brown in color. They are made up of many exposed cells that are less than an inch deep. Nests typically range from the size of a quarter to a coffee can lid, but can be larger.

Although we invite anyone in Washington to participate in adopting a paper wasp nest, we are particularly interested in observations from Whatcom, Skagit, Island, San Juan, Snohomish, King, Jefferson, and Clallam counties.

Paper wasps tending their nest

LOCATE

Starting in June, locate active paper wasp nests that you have access to and can monitor through October. Log the nest locations using the Watch a Wasp Nest Registration Form. After submission, you’ll receive an email confirmation which will include a unique Nest ID assigned to your nest location. You will need to save this Nest ID to use during weekly check-ins. Access the registration form.

MONITOR

Each week visit the nests. Watch for any hornet or wasp activity happening at the nest. WSDA asks you to monitor the nests for at least five minutes during the day once per week, but you can check the nests as long and often as you would like.

REPORT

After monitoring you will need to report each of your observations on the Watch a Wasp Check-in form. You will also need your Nest ID which was received in a confirmation email. Click here to access the check-in form.

However, if you think you spot a northern giant hornet (it will be significantly larger than the paper wasps), safely take a photo and report it at agr.wa.gov/hornets or by emailing hornets@agr.wa.gov.

Stay Connected

WSDA is dedicated to working with the public and to providing information on northern giant hornets.

• Join the Washington State Hornet Watch Facebook group.
• Join the Pest Program email listserv.
• Follow WSDA on Facebook, Instagram, YouTube, and Twitter. 

Cicada killer frequently mistaken as northern giant hornet

Cassie Cichorz
Pest Program

With summer here, people are outside enjoying nature and noticing insects! Citizens are on the lookout and reporting suspect giant hornets. WSDA’s team has been hard at work reviewing hundreds of reports of suspect northern giant hornets. Most of the insects reported are not harmful and play an important role in the environment. One insect, the western cicada killer (Sphecius grandis) seems to be trending as the most common native bug mistaken for a northern giant hornet (Vespa mandarina).

If you can familiarize yourself with some features of the look-alike insect in the spotlight, you’ll be able to identify differences. The western cicada killer is a very common native wasp that can be almost as large as a northern giant hornet. Cicada killers can be seen from late spring and throughout the summer.

Cicada killers can be up to two inches long, just like the northern giant hornet. Differences in their head, thorax, or abdomen will help you distinguish between the two species. The heads of cicada killers are narrower than their thorax, while the northern giant hornet has a head as wide as its thorax. The cicada killer has round eyes, unlike the angular eyes of giant hornets.

The thorax on a cicada killer is reddish in color, while the northern giant hornet’s is black. The cicada killer’s thorax and head are about the same color, unlike the contrasting head and thorax of the northern giant hornet. Both wasps have translucent, amber-colored wings.

You can also check the banding on the abdomen for differences. The northern giant hornet has horizontal lateral bands or striping on its abdomen. The cicada killer’s bands will drop down like teardrops, or have dots between the bands.

Female cicada killers are solitary and dig their nests in the ground. You will often find their nests around areas with lots of sunlight, and sometimes you will see a mound of dirt near the entrance. Cicada killers do not actively defend their nests normally. Males can be territorial, but they do not have a stinger.

Northern giant hornet nests can be underground or in tree cavities. Unlike cicada killers, hornets are social and live in large colonies – which they will vigorously defend. Away from the nest, hornets are typically non-aggressive unless provoked.

WSDA has other information on look-alike insects, including a poster guide available for use and download. Click here to learn more about identification. Cicada killers do not need to be reported, but if you suspect you’ve seen a giant hornet in Washington State or are not sure if what you have seen is one or not, get a photo and report it at agr.wa.gov/hornets.

With hornet trapping, finding nothing means something

Karla Salp
Communications

Trap contents from a brown-sugar-baited trap in
South Korea, including V. mandarinia and V. crabro

The first of July is a much-anticipated time for Washington’s citizen scientists. It marks the start of the Asian giant hornet (Vespa mandarinia) trapping season. For the past two years, citizen scientists have set hundreds of traps to help look for hornets throughout the state.

Yet very few of those traps have actually caught a hornet. Not catching hornets, however, is good – and provides meaningful information.

WSDA entomologists Sven Spichiger and Chris Looney recently returned from a trip to South Korea where they conducted or began various types of hornet research in partnership with some local collaborators in an area where the hornets are well established.

One of the experiments involved placing five traps - like those WSDA and citizen scientists have been using for the past two years - to look for the hornets. The traps used the brown sugar bait option – an option that was added in 2021 in addition to the orange juice and rice cooking wine bait option.

The mini-experiment suggested that when hornets are around, the traps will catch them. Although the traps were placed several weeks before peak worker hornet season, WSDA was able to trap two Vespa mandarinia and six Vespa crabro (European hornet) specimens from June 9 - 24.

When you run a trap and catch nothing, that is a great result! It suggests that there are no hornets where you live. So, even if you are disappointed that you’ve never caught a hornet, please consider being a citizen scientist again and help us monitor hornet populations in the state. Whether you catch a hornet or not, it provides the data we need to eradicate this invasive hornet.

Not up for trapping hornets? You can also join our Adopt a Wasp program, which only requires five minutes per week watching paper wasp nests on your property. 

This summer, "adopt a wasp" to help monitor for Asian giant hornets

Cassie Cichorz
Pest Program

WSDA invites you to help watch for Asian giant hornets (Vespa mandarinia) this summer. Join our new citizen science project to adopt a structure with paper wasp nests and observe the nests weekly from June through October. If you'd like to do even more, WSDA will continue to invite residents to participate in citizen scientist trapping for hornets too.

Over the last two years, residents of Whatcom County have noticed hornets attacking paper wasp nests. In 2021, WSDA tracked a hornet and observed it repeatedly visiting the same paper wasp nest. Each visit lasted five to ten minutes and the hornet removed paper wasp larvae.  

Paper wasps can grow to about ¾ of an inch long and have a well-defined “wasp waist” that makes them easy to identify. Paper wasps are typically not aggressive and do not readily attack people, but they can sting if threatened. They form small colonies and build hanging, open comb nests on building eaves, frames, abandoned cars, or branches of trees and shrubs. Paper wasp nests vary in size and are usually gray to brown in color. They are made up of many exposed cells that are less than an inch deep. Nests typically range from the size of a quarter to as wide as a coffee can lid, but can be larger.

Although we invite anyone in Washington to participate in adopting a paper wasp nest, we are particularly interested in observations from Whatcom, Skagit, Island, San Juan, Snohomish, King, Jefferson, and Clallam counties.

LOCATE

Starting in June, locate nests that you have access to and can monitor through October. Log the nest locations using the Adopt A Paper Wasp Registration Form. After submission, you’ll receive an email confirmation which will include a unique Site ID assigned to your nest location. You will need to save this Site ID to use during weekly check-ins. (Please do not register any sites before June 1.) Click here to access the registration form. When you register, you’ll have the option to sign up for weekly email reminders to check your wasp nests. You can also sign up for weekly text reminders by texting JOIN WASP to 1-800-443-6684.

MONITOR

Each week visit the nests, observe, and report online if any hornet or wasp activity is happening at the nest. WSDA asks you to monitor the nests for at least five minutes during the day once per week, but you can check the nests for as long and often as you would like. 

REPORT

After monitoring you will need to report each of your observations on the Paper Wasp Nest Check-in form. You will also need your Site ID that was received in a confirmation email. Click here to report and access the Check-in form.

However, if you think you spot an Asian giant hornet (it will be significantly larger than the paper wasps), safely take a photo and report it at agr.wa.gov/hornets or by emailing hornets@agr.wa.gov.

Stay Connected

WSDA is dedicated to working with the public and to providing information on Asian giant hornets.

·        Join the Asian giant hornet Facebook group.

·        Join the Pest Program email listserv.

Follow WSDA on Facebook, Instagram, YouTube, and Twitter. 

Asian giant hornets go to school

Karla Salp
Communications

A student examines a hornet larva

While Asian giant hornet queens are still snuggled up for the winter, WSDA’s Pest Program has no time to rest. Winter/early spring is when our entomologists review the previous year’s results and make plans for the coming season.

From the start, an important part of WSDA’s approach to ridding the state of this invasive pest has been public education and involvement, which is what brought outreach specialist Cassie Cichorz to visit a third-grade class at Skyline Elementary in Ferndale last Tuesday.

With a wagon full of hornet memorabilia, Cassie has been visiting classrooms around Whatcom County, bringing the hornet to children class by class. Her impressive collection includes hornets in various life stages, combs from nests, a hornet suit she uses during nest eradication, posters, and – always popular with the students – Asian giant hornet temporary tattoos.

Students giving a thumbs-up for their favorite 
Asian giant hornet life stage

Winter is the perfect time for Cassie’s classroom visits – it is a break from our fieldwork that coincides nicely with school schedules – especially those in areas most likely to encounter the world’s largest hornet.  

Cassie Cichorz calls on a student in the back
of the class while displaying hornets

A former school teacher, Cassie has the skill to effectively engage with students and share her hornet knowledge with school children, teaching them how hornets live, what they eat, how they develop, and the threat they pose to local honey bees. Students also learn what to do if they think they see one: tell an adult who can get a picture and report it to WSDA.

Cassie spent half an hour with the class. While telling them about the hornets, she passed around vials containing hornets at various life stages. Some of the students displayed an impressive knowledge of insect development, naming all of the life insect stages: egg, larva, pupa, and adult.

She also carried around a piece of comb from one of the nests that WSDA eradicated just a few miles from the school. The nest comb was “look but don’t touch” because of how delicate the paper comb is.

A student looks at pinned hornet specimens

Both students and staff were fascinated by the insects and most are excited about the opportunity to see them up close. One little girl was too excited to stay in her seat and kept sneaking up close to Cassie to better see the specimens she had even before they were passed around the room. And one staff member confessed that teachers who had already hosted Cassie in and her wagon of wonders in their rooms were sure to take a selfie with a hornet.

Cassie Cichorz lets students feel her hornet suit

While most students love the presentation, not everyone is so enthusiastic.

“Thanks, I’ll never sleep again,” one student said as Cassie packed up her wagon to head to the next classroom.

Schools in Whatcom County interested in the presentations can contact Cassie. She isn’t able to visit every school in the state, but there are many Asian giant hornet resources on our website, including math and science lesson plans appropriate for grades 6 – 10 from Scholastic. 

WSDA Pest Program trapping season wraps up

Karla Salp
Communications

Each year, WSDA’s Pest Program sets thousands of traps throughout the state to catch invasive species that could threaten agriculture. The program surveys for over 130 pests – most of which have not yet been detected in the state.

Japanese beetles

Dozens of Japanese beetles collected from a single trap

It was a record year for Japanese beetle (Popillia japonica) catches - unwelcome news to farmers and homeowners alike. There was one catch in Washington across the river from Portland, a few as usual near Seattle-Tacoma International Airport, but more than 24,000 in the Grandview area. Catching so many in Grandview this year was surprising considering that only three were caught in 2020 between Grandview and Sunnyside combined.

Japanese beetles devour a 
Grandview resident's roses

The overwhelming number of catches in the Grandview area has many implications. First, WSDA has proposed a 49-square-mile Japanese beetle quarantine to restrict the movement of soil, yard debris, and plant materials that could spread the beetles. Second, WSDA is planning an extensive, multi-year eradication program to try to eradicate the pest – no easy task given the number of beetles already in the area. Finally, WSDA will conduct extensive outreach and trapping in Yakima and Benton counties in 2022. 

Japanese beetles attack over 300 different types of plants including roses, hops, grapes, corn, lawns, and many other crops grown in area gardens and farms.

If there is a silver lining to this beetle infestation, it is that the city, businesses, schools, and people in the vicinity have been open and willing to do what they can to help with WSDA’s response to this invasive pest. Another positive: although nearly 100 traps were placed around area plant nurseries, no beetles were found at the nurseries.

Invasive moths

Male Lymantria dispar

Our trappers set nearly 23,000 traps statewide this year looking for Lymantria dispar – the moth formerly known as the gypsy moth (a new common name has not yet been established.) This moth has devastated forests in the Eastern U.S. where it is established – eating over 300 different types of trees and plants. When there are cycles of large populations, they can strip entire forests from the canopy to the ground, leaving an eerie winter-like scene at the beginning of summer.

This year was a low year for Lymantria dispar catches – only six were found in the entire state. Unfortunately, one of those moths was caught in Eastern Washington just north of Kettle Falls - which is unusual in itself as most moths are normally trapped in Western Washington – and it was also a more concerning variety – Lymantria dispar asiatica, formerly known as the Asian gypsy moth. Lymantria dispar asiatica eats a wider variety of trees (including evergreens) and the females can fly, allowing them to spread more easily.

Apple maggot

Apple maggot fly

Our apple maggot (Rhagoletis pomonella) program continued its work of safeguarding Washington’s global reputation for delicious – and pest-free – apples. The program’s work consists of trapping pest-free areas to ensure they remain pest-free as well as trapping around threatened orchards that are near known apple maggot detection sites.

The good news this year is that many of our main apple-growing regions had no catches at all this year: Adams, Asotin, Benton, Douglas, Franklin, Grant, Lincoln, and Stevens counties. Less encouraging was catching 120 apple maggots in Kittitas County and 843 in Okanogan County.

In areas where apple maggots have been detected outside of the apple maggot quarantine area, the county pest boards are responsible for taking aggressive action. WSDA and the Apple Maggot Working Group (an advisory council composed of state and local government, industry representatives, and researchers) began working last year to examine how best to address the growing apple maggot problem in the unquarantined area of Okanogan County. That effort will continue over the coming months.

Asian giant hornet

Asian giant hornet queen from the
third nest with part of her nest

Our Asian giant hornet (Vespa mandarinia) team had a busy season – finding and eradicating three hornet nests in August and September. Every nest was in a tree cavity, each demanding a creative approach to remove the nest. The most challenging nest was about 15 feet up a tree.

Public trapping and reporting again played a major role in locating the nests – two of the three were located after reports from area residents. Despite existing research indicating that the hornets predominately nest in the ground in their native range, all four nests eradicated in Washington over the last two years have been in tree cavities.

Our hornet program will continue for at least three more years. In order for the hornets to be considered eradicated, we must have three consecutive years with no detections. The biggest challenge to success is the lack of a highly-effective trap. While the traps we use catch hornets, they do not appear to be irresistible to them. USDA continues to work on a lure that will be more attractive to the hornets and we wish them much success!

Exotic wood-boring insects

Velvet longhorn beetle

Many of the pests we look for are never found. Such is usually the case with our exotic wood-boring insect survey. Imagine trapping for years and never finding what you are looking for. As disappointing as it may be not to find anything, that’s exactly what we hope the results will be as we look for potentially harmful new pests.

This year, WSDA put out over 400 exotic wood-boring insect traps at high-risk sites such as ports, shipping distribution sites, and transfer stations. Trapped areas and other high-risk areas are visually surveyed for signs of wood boring insect activity. One day, they found one.

“This is the first time in all of these years I have trapped a target species,” Don Kitchen, one of the members of the beetle survey team, said.

This past summer, the velvet longhorn beetle (Trichoferus campestris) was detected for the first time in the state in King County near Kent. WSDA responded by setting more traps and conducting visual surveys of the area, although no additional beetles were found. WSDA will continue to put out additional traps, conduct visual surveys of the area, and conduct outreach about the beetle in 2022.

The work continues

WSDA’s Pest Program has had a busy year – and this roundup covers just a handful of the pests they monitor. With their continued work and the help of the public looking for and reporting suspected invasive species, our state should be protected from harmful pests for years to come. 

Taking hornet nest removal to new heights

Karla Salp
Communications

WSDA's Pest Program uses a buck lift to access
the nest 15 feet up in an alder tree

Last week, WSDA’s Pest Program removed the third Asian giant hornet (Vespa mandarinia) nest of 2021, making it the fourth nest removed since the invasive hornet was first detected in Washington in December 2019. All of the nests have been in the same general area east of Blaine.

Most research on these hornets suggests that they normally nest in the ground and more rarely in trees. But so far, 100 percent of nests found in Washington have been in tree cavities. The entrance to this latest nest was over 15 feet above the ground. A thermal-imaging camera showed the nest itself was below the nest entrance.

The challenge posed by working on a nest so high up was compounded by the fact that the nest was also surrounded by dense trees and vegetation – especially blackberry patches as much as eight feet tall. The team of entomologists and others from the pest program had to use some new tools to eradicate this nest, including a rented bucket lift to raise them over the bulk of the vegetation so they could work safely at the nest entrance.

Just as in the other nest removals, once at the entrance, the team sealed up the tree and vacuumed most of the hornets out before sealing the entrance.

Inspiring Halloween costumes everywhere -
Dan DeVoe prepares to take down the tree with the nest

In addition to the height of the nest, it was also in a decaying alder tree. This made it risky to safely cut the tree down. A trail steward from the Department of Natural Resources was able to help. Wearing a bulky hornet suit, he cut the tree so it dropped right on target. Once the tree was down, he cut it into sections and split the tree open so the team could finish collecting the remaining hornets and the nest.

Queen and the nest

Here is what was found in the latest nest: 

• 10 combs
• 674 total cells
• 86 empty cells
• 128 eggs
• 202 larvae
• 261 capped cells
• 185 workers
• 0 males
• 1 queens
• TOTAL LIFE STAGES – 777

Luckily, none of the three nests eradicated this year have had new queens, meaning the nest was found and removed before the queens could emerge, mate, and left to start new nests next year.

Two of the three nests this year were found from reports made by local residents, and this is the critical time to find nests before creating new queens. If you think you see an Asian giant hornet, take a photo and submit a report at agr.wa.gov/hornets.

WSDA/DNR/USDA team that removed the 
third nest of 2021, fourth nest total

Video of activity at the nest as well as the nest removal is available on WSDA's YouTube channel. 

Hungry hornet babies – what’s on their menu in the PNW?

Karla Salp
Communications

While the scientific literature indicates what Asian giant hornets eat in their native region, scientists didn’t know what they would eat in the Pacific Northwest – until now.

This story starts at the end - examining the fecal matter, or frass, found in the cells with the Asian giant hornet larvae. To determine what the baby hornets had been eating locally, the WSDA molecular diagnostics lab ran DNA analysis on hornet frass.

The results showed some of what scientists expected – paper wasps and honey bees, for example. But some things – like cow (possibly from a discarded hamburger?) – came as a bit of a surprise. Take a look at what else the hornet larvae have been eating on the menu below.

Finding out what hornets were eating in Washington provides for more than just passing curiosity and a quirky graphic. This information gives a first glimpse at what insect populations could be harmed if the Asian giant hornets establish themselves here.

Visit agr.wa.gov/hornets to learn more about Asian giant hornets.

Top reasons to trap for Asian giant hornets

Karla Salp
Communications

Asian giant hornet bottle trap

With this being National Pollinator Health Week and only days away from the July 1 start for citizen scientist Asian giant hornet trapping, we reached out to our Pest Program and Asian Giant Hornet WatchFacebook group members to get their top reasons (some serious, others...not so much) to trap for Asian giant hornets.

• To help honey bees keep their heads. – Cassie C.
• So I can get some business cards made that say "Citizen Scientist" on them and pass them out. Duh. – Steve S.
• No species of hornet is native to Washington. Let's keep WA hornet-free. – Sven S.
• You might come upon a new odor you have never experienced previously! – Debbie V.
• It is a great way to get kids and kids-at-heart involved in a science project that really makes a difference. – Karla S.
• They are great for stir-fry. Best part is they are already soaked in orange juice and cider. – Lior H.
• I garden and don't want to have the AGH become commonplace for me or anyone else. – Georgia N.
• Because I don’t want my honey bee tattoo to be the only version I get to see in the future. – Becca S.
• I'm SEVERELY anaphylactic and need to stay as safe as possible, so knowing how close the AGHs are is critical to me. – Rhainy C.
• The hornet squad might come over and chest bump after removing the nest. – Rian W.
• Tired of getting "Ancistrocerus sp.", "Polycheirus sp.", "Andrena sp." on iNaturalist. I just want a nice unambiguous chonker insect that doesn't need a microscope to ID to species. – Peter L.
• Because if you trap one, the team in hornet suits might come. – Sven S.
• No packing and mailing in nasty OJ-soaked bugs this year! Unless it is AGH of course... – Karla S.

If these reasons have inspired you to participate in citizen scientist trapping for Asian giant hornets (or you want to trap anyway), get ready now by getting your supplies so you are ready to trap starting July 1. A list of materials and trapping instructions are available on WSDA’s website.

Answers to common questions about WSDA's proposed hornet quarantine

Amy Clow
WSDA Pest Program 

The Washington State Department of Agriculture (WSDA) is proposing to add all species in the genus Vespa (hornet) to the list of quarantined pests. The rule we are proposing would prohibit live life stages of hornet species from being sold, offered for sale, distributed, or knowingly moved throughout or received within Washington.

The proposal adds restrictions to “infested sites,” defined as all property within 20 meters of a nest containing any live life stage of hornet.

The Black Bellied hornet

WSDA will try to notify occupants or owners when their property is designated as an infested site. Until WSDA determines an area is not infested, people will need to get authorization to enter the area. This is to protect the public and prevent more infestation. The proposed rule would allow WSDA to grant access to an infested site to property owners, occupants, and others.

Some frequently asked questions

If a nest is detected on private property, will the owner or occupant be restricted from accessing or entering their property?

No. Access to property owners and occupants will not be restricted. Restricting access within a 20 meter area around the nest is a precaution to protect public health and safety, prevent further infestation, and ensure the nest is safely removed.

WSDA will remove the nest as soon as possible. Nest removal depends on the situation and factors such as weather, obstructions, and equipment availability. Generally, removal will take no longer than two weeks. 

Will yellowjackets or bald-faced hornets be included in the quarantine?

No. Yellowjackets and bald-faced hornets are not included in the proposed quarantine. Yellowjackets belong to the genus Vespula and Dolichovespula. Bald-faced hornets (Dolichovespula maculata) are a type of yellowjacket and not a true hornet (Vespa).

Why are all hornets being quarantined rather than only Asian giant hornet?

No hornet species are native to Washington State. Any hornet introduced here could upset our state’s ecosystem, such as spreading new pathogens and parasites to native wasps, bees, and yellowjackets. Washington’s suitable habitat for certain hornet species make it more likely they will become established once introduced.

Asian giant hornets on a notebook.

The recent detection of Asian giant hornet caught the attention of Washington state residents, but that’s only one reason for the proposed rule. It’s also needed because other hornet species have been detected in Washington and neighboring British Columbia (Vespa orientalis, Vespa soror, and Vespa crabro).

What risk do hornets actually pose?

Hornets pose a direct and indirect risk to agricultural crops in Washington State. They have been known to feed on fruit such as pears, peaches, plums, grapes, berries, and apples, making the fruit unfit for human consumption. Hornets attack honey bees and native insect populations. Managed honey bees and native insects are important pollinators vital to agricultural production. If hornets were to become established in Washington, our economy and ecology could be severely affected.

Hornets can also pose a risk to human health. The venom in their sting can be toxic. And unlike bees, they can sting repeatedly. A hornet sting can cause substantial pain, as well as tissue damage. In some extremely rare cases, death can also occur. Although hornets don’t generally target people, they can attack when threatened.

Visit agr.wa.gov/hornets for more information on the Asian giant hornet, or the WSDA rulemaking page for information on the proposed hornet quarantine rule.

A nest by the numbers - what WSDA found inside the Asian giant hornet nest

Karla Salp
Communications

A new Asian giant hornet ready to emerge

More than 500 Asian giant hornet specimens in various stages of development were collected when entomologists found the first Asian giant hornet nest in the United States.

But finding the nest was just the first step in the eradication. After the discovery of the nest site, WSDA entomologists had to safely remove hornets living in the nest, remove the tree, and finally split the tree open to reveal the nest inside.

After opening the tree containing the Asian giant hornet nest on Oct. 29, WSDA entomologists still had a lot of work to do to collect data about what the nest contained. Much like the election, the tallying took quite a bit of time and, to some extent, continues. 

Pupae in various stages of
development taken from the nest

The nest was just over 8 feet high in the tree and, once opened, was found to be about 14 inches long and 8 to 9 inches wide. Here are the preliminary results of what our entomologists found in the nest.

• 6 combs – There were six layers of comb in the nest. Combs are the structures that hold the hornet larvae as they develop. Part of the interior of the tree had been chewed away to accommodate the combs.
• 776* cells – The combs are made up of cells and each individual cell can hold a developing Asian giant hornet. *This number is approximate as there was some damage to the combs.
• 6 unhatched eggs – These eggs were all located in the last and smallest of the combs.
• 190 total larvae - The larvae are whitish “grubs” in uncapped cells. Many had fallen out of the combs into the tree cavity during the nest removal.
• 108 capped cells with pupae – Pupae are the next stage after larvae. Based on the size of the cells, most of the pupae found are believed to be pupae of new virgin queens.
• 112 workers – This total includes 85 workers that were vacuumed out of the nest on Oct. 24. All of the workers survived being vacuumed out of the nest.
• 9 drones – Drones are male hornets and they generally emerge from the nest before the new queens emerge.
• 76 queens – Most likely all but one queen would be new virgin queens. New queens emerge from the nest, mate, and then leave to find a place to overwinter and start a new colony the next year.

Despite multiple applications of carbon dioxide, removal of the workers, and storage in a cold facility, most of the specimens were still alive when the nest was opened.

Where we go from here

Nest reassembled in the tree

WSDA will continue trapping through at least Thanksgiving and possibly beyond, but will likely only track worker hornets. Our entomologists will not, for example, track new queens if any are captured as they are unlikely to return to a nest, but instead will attempt to locate a mate. Even if no other hornets were to be found, WSDA will continue to trap for at least three more years to demonstrate the area is free from Asian giant hornets.

WSDA’s Pest Program still hopes to eradicate Asian giant hornets from the Pacific Northwest in cooperation with our neighbors to the north in Canada. The effort will take require international cooperation, research for better detection tools, and the continued work of vigilant observers from the public to prevent Asian giant hornets from gaining a permanent foothold here.

If you may have seen an Asian giant hornet in Washington State, report it with a photo if you can get one at:

• agr.wa.gov/hornets
• hornets@agr.wa.gov
• 1-800-443-6684

If you believe you have seen an Asian giant hornet but live in another area, please report it to your state or province’s invasive species managers.

Additional photos of the nest examination can be found on our Box account. When using the photos, please credit the Washington State Department of Agriculture. You can also watch a recording of the press conference on YouTube. 

Stirring up a hornet's nest - safely

Karla Salp
Communications

For WSDA’s Pest Program, persistence has paid off.

Months of researching, planning, and trapping finally led to the discovery of the first Asian giant hornet nest in the United States. The nest was found inside a tree cavity.

After vacuuming 85 hornets from the nest last Saturday, the entomologists in our Pest Program completed the second phase of the project by removing the portion of the tree with the nest on Oct. 28. When they cut into the tree to get to the nest, two queens emerged.

Opening the tree and nest

Early in the morning of Oct. 29, WSDA Pest Program staff gathered at the Washington State University Puyallup Research and Extension Center where the cellophane-wrapped log holding the nest was placed in a walk-in cooler. The cool temperature was meant to help keep any live Asian giant hornets less mobile.

In preparation for splitting the log, the team partially removed the cellophane covering it and pumped more carbon dioxide into the tree. They used a circular saw to cut partway through one side of the tree to help the tree split evenly and create a spot to insert a metal wedge. Once the wedge was inserted, one of the team struck it with a sledgehammer, splitting the log open.

The team went into a flurry of action to collect Asian giant hornets that had remained in the log, many of them still alive, though none flying. Numerous adult specimens were collected and there appeared to be both new queens and workers in the nest.

Once the adults were collected, the team set about removing and analyzing the remainder of the nest. They found several larvae in the nest and many white-capped cells with developing adults.

They also found the radio tag they had lassoed to the Asian giant hornet that led the team to the nest. It appeared to have been chewed off.

Still time to trap hornets and find another nest in 2020

Over the next several days, WSDA entomologists will continue to analyze the nest and its contents. They will record data such as the number and caste of adult specimens, the number and size of the nest cells, overall nest size, weight and length of collected specimens, and more. All of the data will be made publicly available when it is complete and will be posted to our Asian giant hornet webpage at agr.wa.gov/hornets.

Although the first nest has been found, this is not the end of the story. Work continues for WSDA’s Pest Program as well as some citizen scientist trappers in Whatcom, Skagit, Island, and San Juan counties who are keeping their traps up until at least Thanksgiving. There is still time to find another nest this year and residents are still asked to report Asian giant hornet sightings (with a photo if possible) online, via email at hornets@agr.wa.gov, or by calling 1-800-443-6684.

WSDA staff left to right: Rian Wojahn, Chris Looney,
Sven Spichiger, Jessica La Belle, Cassie Cichorz, Karla Salp

More resources:

• Photos of the tree removal
• Video of the tree removal
• Photos of opening the nest
• Video of opening the nest
• Video statement on tree removal and opening nest 

Why don't we import Asian honey bees?

Chris Looney

WSDA Entomology Lab

Photo credit: Flickr user budak

While Eastern honey bees do have a defense against Asian giant hornets, importing them into the United States would do more harm than good. 

The Eastern honey bee, Apis cerana, is one of about 12 different cavity and open-nesting honey bee species that occur in Asia. Apis cerana is widely kept by beekeepers in Asia, but in commercial operations it has been mostly replaced throughout its range by the western honey bee, Apis mellifera. 

The western honey bee, which is native to Europe, Africa, and western and central Asia, has been widely adopted because of its ability to produce higher honey yields than A. cerana. Other factors that make A. cerana difficult to manage for large-scale commercial pollination and honey production include seasonal migration, and a tendency to “abscond” (abandon their hive) when disturbed.

There are other reasons to be wary of importing Apis cerana. Although Apis cerana has effective behavioral defenses against the Asian giant hornet, it is also host to multiple parasitic mites that can destroy colonies of A. mellifera. One of these, Tropilaelaps clareae, has not yet reached Europe or the Americas. Many entomologists believe that Tropilaelaps could be more devastating to U.S. honey bees than the Varroa mite, and annual nationwide monitoring of U.S. honey bee populations to prevent the establishment of this parasite is a high priority of USDA-APHIS.

Importing A. cerana might also provide a pathway for bee viruses to enter the U.S., creating a high risk to both managed Apis mellifera populations and native bee species. Finally, Apis cerana itself could be problematic. After being introduced to Australia and Papua New Guinea, it became highly invasive and displaced native bee species. All efforts to suppress it have so far failed.

Intentionally introducing A. cerana would pose a huge risk to U.S. agriculture and native bees, and is not currently a viable solution to managing Asian giant hornets even if they become established. It is also illegal under federal law.

As a final note, remember that beekeepers still raise western honey bees in places where Asian giant hornet is native. It takes more resources, but the industry is viable.

Contributed by Katie Buckley, Steve Sheppard, Brandon Hopkins, and Chris Looney