What PMPs need to know about the Asian giant hornet

The large yellow-orange head and dark eyes and dark thorax
distinguish the Asian giant hornet from similar large wasps.
Photo courtesy Washington State Department of Agriculture.

If ever there was an insect pest designed to generate fear and panic, it would be the Asian giant hornet, Vespula mandarinia. The largest wasp in the world, with a sting once described like a hot nail being punched through the skin, we should give this wasp credit. It is one scary dude (or more accurately dude-ess).

Adding to the hornet's fearsome reputation is it's impact on honey bees. One of the favored foods for the Asian giant hornet is the brood and workers of social wasps and bees, including honey bees. In the fall hornets start actively searching for bee and wasp nests.  Once a nest is discovered, the hornets overpower the inhabitants, bite off their heads and consume the brood and honey [in the case of honey bees].

Commercial honey bee apiaries are especially vulnerable to hornet attack because of the close spacing of hives.  An apiary can quickly turn into a scene of pillage and destruction as wasps move from hive to hive.

So that's the essence of the bad news that you can read in most media accounts of the hornet. Here are a few things every PMP should know about this hornet as you talk with your customers. 

Background

The largest wasp in the world, the Asian giant hornet is
1 to 1 ½ inches long with a ¼ inch-long stinger.  Photo
courtesy Washington State Department of Agriculture.

The Asian giant hornet was first detected in September, 2019 on Vancouver Island in British Columbia, about 200 miles northwest of Seattle, WA.  In December, three months later, a dead wasp was found in the small town of Blaine, Washington (100 miles north of Seattle) and reported to the Washington Department of Agriculture.  It was confirmed as the first detection of Vespa mandarinia in the U.S.  As of last February according to the USDA, so far a total of six sightings have been confirmed from British Columbia and Washington State (September through December).

You need to know. So far this wasp is only found in Washington State and British Columbia.  There is practically zero chance that anyone outside northwest Washington and southern BC will encounter this wasp this year.  Most of your experience with this wasp will be explaining to customers why they are not the first house in their state to get Asian giant hornets, aka "murder hornets" (more on identification tips below).

Spread

Asian giant wasps from Japan (A, B), India (C.) and Washington state
(D) show some color variability, but all have the distinctive yellow-orange
head with dark eyes. Photo credits: Yasunori Koide, Wikimedia Commons
(A); Alpsdake, Wikimedia Commons (B); Chief Red Earth,
https://indiabiodiversity.org (C); Sven-Erik Spichiger, Washington State
Department of Agriculture (D). Composite image from USDA
APHIS response guidelines 2020.

Researchers are still unsure how the Asian giant hornet made its way to North America, but suspect that mated, overwintering queens may have been transported in soil-containing plant pots shipped from Asia. A similar route of entry was responsible for introducing another Asian hornet to France a few years ago.  Recent genetic analyses suggest that the wasp was introduced on at least two occasions very recently.

You need to know. Human transport of the wasp has occurred but it is likely a rare event.  It is more difficult to transport a social insect, because it must be transported either as a mated queen or as an intact colony.  Individual hornet workers do not survive long if separated from their colony.  In my opinion, this means that, given reasonable precautions, we shouldn't expect rapid spread of this wasp throughout the states.  On the other hand, it is estimated that the wasps would be capable of surviving in plant hardiness zones 6 and above, which means that about 2/3 of the U.S. may ultimately be capable of supporting this hornet.

Activity

Like our smaller, ground-nesting yellowjacket wasps, Asian giant hornets build underground nests that survive for one growing season.  Queens leave the nest with the coming of cold weather and overwinter in protected hiding places until mid-spring when they emerge and hunt by themselves. Small colonies are formed and by early- to mid-summer worker wasps are produced and cooperative nest building proceeds. Not until fall do these wasps go on their campaigns of slaughter and occupation of bee hives.

You need to know.  Most people will face little risk of stings from Asian giant hornets.  These insects are aggressively territorial only when their nest is disturbed. Nests are usually found in wooded areas and only occupied by guard hornets from mid-summer through the fall. If their biology turns out to be similar to our native yellowjacket wasps, most nest encounters (and stings) will occur after the nest grows in size in late summer and fall (September and October). There is a more limited time frame in the fall (October and November) when honey bee hives are at risk from attack by wasps.  Fall will be the time to be most concerned about stings and beehive attacks from these wasps.

Identification

This may be the most useful information in this post, as most of a PMP's role will be reassuring the public that any big insects they see are NOT Asian giant hornets.

Since this is the world's largest wasp, the first thing is to measure its length.  Workers range from 20 to 40 mm-long (up to 1 ½ inches) and queens up to 45 mm (2 inches).  While coloration patterns can differ, the most distinctive and prominent feature is the yellow head that contrasts with dark eyes and thorax. See this useful chart published by the Washington State Department of Agriculture and this training slideset developed by USDA APHIS.

North American social wasps similar to Vespa mandarinia. (clockwise from left) A. European giant hornet (Vespa crabro); B. Bald-faced hornet (Dolichovespula maculata); C. Western cicada killer (Sphecius grandis); D. Eastern cicada killer (Sphecius speciosus); E. Pacific cicada killer (Sphecius convallis). From New Pest Response Guidelines for Vespa mandarinia, USDA APHIS, 2-2020.  

The closest relative of the Asian giant hornet is Vespa crabro, the European giant hornet. In the south and west, cicada killer wasps are the most common giant hornet look-alikes, reaching up to 1 ½ inches in length, but are generally more slender and lacking the large yellow-orange head and contrasting black eyes.

You need to know. There are lots of big insects that people will mistake for Asian giant hornets.  The chance of encountering one of these invasive hornets outside of Washington state is about zero right now. But be ready to put a name on the insects your customers will bring to you.

Hornet vs. Wasp

In this post I've used the terms hornet and wasp almost interchangeably. That is because hornets are a kind of wasp.  The term wasp refers generally to any member of the insect order Hymenoptera that is not a bee or an ant.  Most of the stinging wasps we think of as pests belong to the wasp family Vespidae.  The term hornet refers to vespid wasps in the genus Vespa.  In the U.S. we have only two species of hornet, the European giant hornet and (now) the Asian giant hornet. Despite its common name, the baldfaced hornet in the genus Dolichovespula is considered a type of yellowjacket wasp, so is not technically a hornet. 

You need to know. There are only two true hornets in the U.S., however, the smaller yellowjacket wasps and Polistes paper wasps are also social and will aggressively defend their nests like hornets and some bees.  Any of these species can be considered pests when their nests are built in areas where people travel or live.

Control

Japanese hornet-hunters wear special protective gear to excavate a nest.  These special suits are designed to be slippery so the hornet cannot hold on; and are made of tough fabric that keeps stingers from penetrating. Note the use of smoke to calm the hornets while removing brood for human consumption. Photo credit Nonaka, 2008. From USDA APHIS 2020.

A variety of approaches have been taken to control the Asian giant hornet, but none seem capable of eradicating the pest at this time.  The USDA APHIS recently published response guidelines for the Asian giant hornet which includes a summary of different control measures with pros and cons of their use. Pest management professionals who encounter this hornet should be aware that traditional bee protective suits are not adequate protection for the one-quarter inch stingers carried by this hornet. In Japan special suits are sold ($700-$900) to protect people exterminating or digging up hornet colonies for food.

You need to know. Killing individual wasps through baits or sprays will not control this species. Locating and exterminating the nest is what is being attempted in Washington state right now. Anyone who encounters a suspected Asian giant hornet should contact their state department of agriculture or a university entomologist.  Do not attempt to remove or kill a suspected Asian giant hornet nest without adequate personal protective equipment.

Reading your first scientific review paper

Feeling scholarly? Today might be the day to kick off your shoes, put up your feet, grab a favorite beverage and read a scholarly review paper.

The Journal of Integrated Pest Management is a relatively new, open access (meaning free!) publication put out by Oxford Press and the Entomological Society of America.  Its purpose is to provide a place for researchers to publish reviews of the literature concerning significant pests.

Most of the papers appearing in the JIPM summarize current knowledge about the control of an agricultural or horticultural insect, weed or disease pathogen.  But this month a paper of interest to pest management professionals was published on brown recluse spiders.

Rick Vetter and Stoy Hedges, both long-time friends of the pest control industry, have teamed up to write a paper on current practical knowledge about the biology, importance and control of Loxosceles reclusa, better known as the brown recluse. Although both authors are well-published, Hedges admits the paper marks an especially sweet accomplishment for him, as his first paper in a refereed scientific journal.

What's a refereed article?

If you're a PMP and never read a scientific journal paper before, this could be a good one to start with.  But first, just what is a "refereed" journal article? If you've ever heard the old line, "publish or perish" as applied to college professors, the term publish generally refers to refereed journal articles or scholarly books. The "perish" in the saying is almost literal and refers to holding onto or losing your job as a professor. To avoid perishing professionally, it is almost universally true that professors must write refereed articles.

A refereed article is first and foremost a scholarly paper, written by someone who has become learned through study and/or research. Scholarly papers are not meant to entertain, but to precisely explore, inform or enlighten a reader on a topic.  Scholarly papers don't have to be dull or difficult to read (though many are), but they do have to be based on data, sound observation or logic. To ensure this is the case, all must go through a rigorous process of peer review and critique by fellow, equally qualified scientists or scholars.

To publish, Vetter and Hedges first wrote their paper and submitted it to the editor of the JIPM.  The editor then read the paper, made sure it was readable, whether the authors followed journal instructions, and whether it was appropriate for the journal. Once it passed the editor's initial review, willing reviewers with knowledge of spiders or urban pest control were identified and the paper was sent out for review.  Three (usually) reviewers read and commented on the paper, offered suggestions and told the editor whether they thought the paper was OK, whether it needed revision, or whether it was so bad it shouldn't be published. Only after it passed the reviewers' and editor's approval, was the paper approved for publication. Many, if not most, publications get rejected by reviewers at least once. If you look closely at these papers you can almost see the blood, sweat and tears... sometimes from both authors and reviewers.

By the way, reviewers are volunteers. If you are a professor or scholar who has previously published you might be asked to review a paper in your published field. This in itself is considered a scholarly activity and professors are graded by their institutions, partly, on how many papers they have reviewed in a given year. Reviewing a paper is a lot of work, but science could not advance without good reviewers.

The abstract

Most scientific publications have abstracts, usually at the beginning of the paper.  This is one of the most useful parts of a scientific paper. The abstract should summarize the reason for, and the key findings of, the paper.  Unlike a book description on the dust cover of a novel, the abstract should give away the ending. It should be short, but thorough enough to tell the reader what the paper is about, and its conclusions.  In a given year I read relatively few papers from start to finish, but I read a lot of abstracts. They are great time savers.

Vetter and Hedges' paper is a particular type of scholarly article called a literature review. Rather than writing about original research they conducted, they have summarized others' research and put that information into context. As the authors say in the abstract, "...we review biology and life history of the brown recluse spider as it relates to pest management as well as control measures as they pertain to an IPM strategy..." The best literature reviews are written by scholars who know their subject matter well enough to explain not just what another researcher published, but why it's important.  Literature reviews are one of the most important types of publications for new readers on a topic.

Citations

A literature review is typically peppered with citations--abbreviated references to refereed papers or books. You'll see lots in this paper. Citations generally include the first author, or two co-authors names, and the year of publication. For example, (Thoms and Scheffrahn 1994) refers to a paper by two researchers, Ellen Thoms and Rudi Scheffran, published in 1994 on the control of pests using Vikane gas.  The full reference citation is found in the section in the back of the paper, usually in the section labeled as References Cited. When the article has more than two authors it will be referred to by the primary author's name followed by et al. For example, Atkins et al. 1958 refers to a paper by J.A. Adkins and three other collaborators, Wingo, Sodeman and Flynn, published in 1958 on "necrotic arachnism" (spider bites that result in flesh-eating, slow-to-heal wounds).  Sounds like a real page turner.

Like all of us, scientists have egos; and having your name first in the list of authors is a badge of honor. Being first usually means that you led the study or done most of writing on the paper.  Surprisingly, being last in a list of authors is often considered second best. Last place is often reserved for the supervising professor (if the first author is a student), or someone responsible for securing project funding. Being stuck in the middle of a long author list is like being the "middle child"--more likely to be overlooked and forgotten.

Let's Read

That's really all you need to know to read this paper. It's more engaging (and you are less likely to fall asleep) if you use a highlighter to mark things new to you, or which might be relevant to control of these spiders. For example, several years ago I did some insecticide tests on brown recluse spiders, so I was especially interested in the review of insecticides that others found effective. I also know from talking with fumigators that spiders are notoriously hard to kill with fumigants. So I was interested to learn that Thoms and Scheffran determined that a 1.5X rate of Vikane was needed to kill brown recluse spiders. I highlighted both of these sections.

Lastly, remember that even writers of scholarly papers are ordinary people--sometimes a little geekier or nerdier than some of your football-watching buddies, but still just people who put their pants on one leg at a time. Even scholars make mistakes, overlook data, and draw bad conclusions. Even though peer review is a rigorous process, it's not perfect. To me, that makes reading science papers more interesting. It means that they should always be read critically, with an eye to your own experience and to common sense.

When you're done, take the paper and file it. I have a My Library folder on my computer. This article went into a sub-folder on spider papers.  Whatever system you use, put it somewhere you can find it later. Otherwise you will forget most of what you've learned and highlighted.

So grab a cold one and dig in. There's a lot to learn about spiders in Vetter and Hedges 2018.

ACE Prep Class offered next week

Students taking their exams after the 2012
ACE Prep class at Texas A&M. 

I often get asked how best to study for the ACE exam, and if a class is ever offered. One of the places to get ACE training each year is the Texas A&M University Urban Pest Management Conference. If you're not familiar, this is the biggest CEU opportunity offered by the A&M entomology department, and (we think) one of the best training opportunities for PMPs in the state.

As of this morning enough students have signed up for this class to make it a go, and there is room for more.  If you are interested in participating, just go to the A&M Conference website and sign up.  You will be registering for the whole conference that runs from January 10-12.

ACE training runs all day on Wednesday, Jan 10, beginning at 10:15 am.  We will cover as much of the ACE exam material as we can in one day.  On Wednesday, we will offer an opportunity to take the ACE exam for anyone who is ready to take it.

Not enough notice?  I plan to offer the prep class as an IPM Experience House event at our Texas A&M AgriLife Center in Dallas twice in 2018 (dates to be determined). If you are interested, drop me an email--or even better, join our mailing list at the IPM Experience House website. This will get you notified of all IPM House activities coming up in 2018 if you join the list.

A loss for Dallas Pest Control

I know that many of the readers of this blog are not from the north Texas area, so sharing news of a local nature may be a turn off for some.  But there is something universal about the loss of a colleague that should cause all of us, no matter where we live and work, to pause and reflect.

Last week the Dallas pest control community lost a friend in Ray Porter.  I knew Ray from several projects we got to do together (meaning he was willing to help me out on some field trials) well over 10 years ago. He was one of the nicest guys I've been privileged to work with, always unassuming and extremely polite. Ray was an account manager for Orkin Pest Control from 1989 -1998 and then with Bizzy Bees Pest Control in Dallas from 1998 – 2013.  He became an Orkin man again when Bizzy Bees was bought out in 2013, until 2016 when he retired. According to his friend Errol Cohen, he was "devoted to his customers beyond belief, and always delivered exceptional service... Always a top performer and a President’s Club member numerous times, Ray went way beyond the extra mile every day."

Ray also went the extra mile for his profession.  He was active for many years in our local pest control association, working to build relationships among fellow professionals and trying to raise the reputation of the industry. In this regard his life should be an example, especially to the newer pest management generation.

It's sad when a good man passes away, but Ray's passing reminds me that we all are privileged to work daily with some pretty great folks. Let's not forget to appreciate them while we have them, and to enjoy the time we are given.  So long Ray, and thanks for your example and inspiration.

I remember being told by a customer in my first job in pest control, that a company is only as good as the people it employs. By this standard, Orkin and Bizzie Bees were definitely winners.  From Ray's obituary:

Raymond Nelson Porter was born August 14, 1942 in Sand Springs, Oklahoma to Harry and Bertie Porter and died peacefully August 10, 2017 at home surrounded by family. Ray was devoted to his wife and family (especially his grandchildren and great-grandson). He was an avid golfer, loved being outdoors and working at Bizzy Bees. Survivors include his wife Yvonne of 28 years; his son Eric Porter (daughter-in-law Stacy, grandson Brandon and wife Molly, great-grandson Luke and granddaughter Tiffani); his son Christopher Porter (daughter-in-law Carol, grandchildren Claire and Nicholas); his son Jason Porter (granddaughter Lindsay); his step-daughter Andrea Hefner (son-in-law Bill, granddaughter Alexandra and husband Colman, and grandson Riley); his step-daughter Stephanie Enriquez (grandsons Steven and Christopher); his sister Sue Orendorff (brother-in-law Ellis); and, his brother Larry Porter.

A Memorial Service will be held Saturday, August 19, 2017, 10:30 am, at Williams Funeral Home, 1600 South Garland Avenue, Garland, Texas 75040.