Entomologists Ignite in Denver: Part II.

In the first of my two posts about the annual conference of the Entomological Society of America (ESA), I covered some of the non-urban entomology sessions.  In today's post, I'll review some things that are a little more relevant to the business of pest control.

Technology and urban pests

While sitting through some papers at ESA that went way over my head, it occurred to me that entomology has changed a lot since I went to school. One of the biggest changes is in technology. Today's technology is much more sophisticated, and enables us to study insects in ways we could only dream of a few years ago. For example, our ability to amplify minute amounts of DNA from an insect's stomach lets us know what kind of bacteria live there, or what the insect's last meal was. Amazing.

Wooden stake with Formosan termites. Unlike drywood termites,
which get their nitrogen from the air, subterranean termites
appear to get their nitrogen from ingesting soil. 

In one sense, this growing sophistication is a good thing.  It means that researchers now have better tools to understand the basic biology of insects.  On the other hand, there appears to be a trend in many universities to shy away from practical applied research and focus more on shiny new techniques and tools. In hallway conversations with industry reps, I'm told it's easy for hiring companies to find a young entomologist who knows her way around a genetics lab, but increasingly hard to find one who knows their way around a cockroach-infested apartment or a PMP's tool box.

One of my favorite student papers, with a balance of good basic science and applied biology, was also one of the shortest.  Aaron Mullins, University of Florida, explained in his three minute (!) paper that biologists have long known that drywood termites get much of the nitrogen (N) they need from the air (N is an essential element for protein building and reproduction). This makes sense because drywood termites live entirely in relatively low N-containing wood. Mullins wondered if the same was true for subterranean termites. He found that Formosan termites housed in organic (N) rich soil grew their colonies 10X as fast as similar colonies living in clean sand. He concluded from this and other evidence that subterranean termites get their N from the soil rather than air.  I'm not sure of the long-term impacts of this new discovery, but it will likely affect how we rear termites in the lab for experiments.

Jose Pietri with Apex Bait Technologies gave an interesting paper with potentially big implications. Testing the hypothesis that symbiotic gut microbes might play a role in cockroach resistance to insecticides, Pietri and colleague Dangshang Liang fed insecticide-resistant cockroaches a bait mixed with an antibiotic, doxycycline. They found a significant  increase in mortality from the bait with doxycycline compared to bait without the antibiotic. When the antibiotic bait was fed to insecticide-susceptible strains, however, it was no more effective than the bait without antibiotic. If confirmed, this might prolong the usefulness of some insecticide active ingredients for resistant cockroaches.

Ed Vargo, of Texas A&M University, reported that tawny crazy ant, Nylanderia fulva, infested five new Texas counties in 2017, bringing the current total to 39. He found that ants from different crazy ant colonies were not aggressive to one another, and he used sophisticated genetic tools to discover that there were no significant genetic differences among nests in a site or between states. These data suggest that TCA has extended colonies that might range over many miles.  This diffuse nest structure, similar to Argentine ant, at least partly explains why TCA is so difficult to control.

Bed bugs

Are even entomologists getting weary of bed bugs? Maybe. Bed bugs were the subject of 31 papers and posters this year, down from last year's 46 (and a record 56 papers in 2011).  Most of this year's talks were given during a symposium called Advances in the Biology and Management of Modern Bed Bugs. The session featured authors of a new book of the same name to come out in 2018.  If you dig scholarly work on bed bugs, this might be a nice addition to your library--if you can afford it (listed at $200, not unusual for academic books). According to the publisher, it will be the first comprehensive academic review of bed bugs since 1966. NPMA attendees will recognize the names of many U.S. authors like Rick Cooper, Changlu Wang, Dini Miller, and Jim Fredericks.  And there will be a number of international authors as well.

I'm saving up for my copy, but the title got me wondering, "What's a modern bed bug?" So I asked Dini Miller, of Virginia Tech and one of the editors of the book.  She replied that "these are not your grandmother's bed bugs." These are the "incredibly resistant" bed bugs that have made their comeback over the past 20 years. Modern bed bugs have thicker cuticles to resist insecticide penetration, tougher nerves, and better enzymes to detoxify these insecticides. Given that the tropical and the common species of bed bug both have developed these characters, the book theorizes that malaria control programs in Africa, where both species live together and are regularly exposed to DDT and pyrethroids, may have been the breeding ground for these new "super bugs."  Anyway, there is obviously a need for an updated book on on bed bugs.

Research Highlights

Today's bed bugs are more difficult to kill with insecticides. All
the more reason to use a variety of control tactics.

The Highlights of Urban Entomology session is one of my favorites for catching up on papers I may not have had time to read this year. This year's presenter was Chow-Yang Lee, Professor at the Universiti Sains Malaysia, and soon to be with the University of California at Riverside. He and colleagues recently reviewed the literature and found that resistance to chlorfenapyr (Phantom) is "brewing" among modern bed bug populations. Also, bed bugs tested recently from Cincinnati and Michigan show moderate to high resistance to neonicotinoids used in products like Temprid and Transport, Mikron and Tandem. If you had hope that baits might be the answer, a study by Yvonne Matos and coauthors found that secondary kill of bed bugs is much lower than for cockroaches. Even if a suitable way to bait for bed bugs was found, current evidence suggests that baits would likely not be as effective as cockroach baits.

Finding better formulations is a productive field for improving pest control. Vander Meer and Milne reported improved control of fire ants with a waterproof formulation of Distance fire ant bait. Made from dried distillers' grain with solubles and shrimp shells, it outperformed standard corn grit baits. This formulation will likely be more effective as a control for red imported fire ant and little fire ants, especially in wetter locales.

Literature reviews are papers that synthesize lots of scattered research into something that makes sense of the topic. A good literature review is invaluable, especially if you're not an expert. So, I was glad to learn of a new (and free via this link) literature review on fleas, recently completed by the venerable urban entomologist, Mike Rust. Rust looked at some of the more recent advancements in flea borne diseases, new control products, and resistance to insecticides. Contrary to what you might hear from pet owners, there is little evidence that fleas have developed resistance to the very powerful on-animal treatments like fipronil, imidacloprid or lufenuron. On the other hand, pyrethroid resistance by fleas is becoming more widespread. While on-animal treatments solve most problems, pyrethroid resistance poses a dilemma for PMPs needing to treat flea infestations that arise from non-pets, such as feral animals (in a crawl space, say, or in backyards). Not many non-pyrethroid broadcast spray alternatives are available for this task.

Certification

Lastly, I had the opportunity to attend a committee meeting on the ACE (Associate Certified Entomologist) program. This is a program for anyone in pest control who wishes to identify themselves as a certified entomologist. Since last year, Willet Hossfeld has taken over administrative duties for the Certification program.  He reported that there are currently 1025 active ACEs nationwide, with 267 in the application process. If you ever have a question about the certification application, he's the one to contact.

The main topic of discussion by the support committee this year concerned the difficulty of the certification exam (40% pass rate on first try), and how that has discouraged many highly qualified folks from taking it. Several at the meeting noted how useful the study guide that I and Richard Levine co-authored a few years ago, has been.  But there still seems to be a need for group prep classes to better prepare ACE candidates for the exam.  The committee took steps to begin updating the practice exam for those preparing for the test, and discussed how to make more prep classes available.  A prep class PowerPoint set has long been available to anyone who wants to conduct a prep class. This PowerPoint set will be revised and updated in 2018.  Any BCE or ACE who wants to sponsor a prep class, should contact Willet at ESA and he can tell you how it's done and how to get a copy of the prep materials.

You're Invited

Pest management professionals also attend these national meetings. If you haven't yet attended, I encourage you to give it a try (the next two meetings are in Vancouver BC in 2018, and St. Louis MO in 2019). The meeting is a great time to make new friends and professional contacts; and while it's not all pest management oriented, there are always good urban entomology sessions featuring cutting edge research. If you decide to attend, don't be shy--introduce yourself to speakers and others in hallways. Consider attending the Certification Board meetings; visitors are welcome. And bring a few extra bucks for a t-shirt or pet tarantula. Your coworkers will look at you strangely, and you'll know what it's like to call yourself an entomologist.

Urban entomologists in Georgia

Atlanta is home to historical memories of the Civil War and William T. Sherman's infamous march to the sea. It's also known for its peaches, the Atlanta Braves, Coca Cola world headquarters, and the Jimmy Carter Presidential Library.  It is lesser known as the home of Rollins Inc. and the Orkin University and Training Center, a state-of-the art training facility for Orkin sales and pest control staff. It is also lesser known for being the probable entry point into the U.S. for a new invasive insect known as the kudzu bug.

Orkin Trainer Jose Dolagaray explains the design and use of the
termite training facilities to conference attendees visiting the
Orkin University and Training Center at Rollins headquarters.

The last two points were of great interest last week, at least to the 220 or so entomologists attending the 2012 National Conference on Urban Entomology.  This is the largest conference in the U.S. (and likely the world) focused solely on the science of urban entomology, and is a great place to hear the latest news and research on bed bugs, cockroaches, termites, and many other urban insect pests.  Of the 43 talks I attended over three days, some of my personal highlights included the following reports [my apologies ahead of time to termite people--most of the talks I attended were bed bug-related]:

• Dini Miller of Virginia Tech provided a very practical case study of failure to control cockroaches in what she said was the worst multifamily housing cockroach infestation she had ever encountered (and for Dini, that's saying a lot). Student researchers averaged 200 cockroaches per unit per night in 36 "high-clutter and poor sanitation" apartments in a city housing authority. Miller showed that baits can be effective in such poorly maintained apartments when the infestation was reduced significantly with a simple service involving application of 30 grams of gel bait per unit followed by a 14-day followup treatment.  When the units were turned back to the pest control company for maintenance, the populations increased to above the previous infestations within 4 weeks.  The reason? One technician was not sufficient to service the number of cockroach infested units in the complex, and not enough bait was being used in each unit to halt cockroach population growth. Miller showed that 45 minutes was required to put out an average of 916 grams of bait per unit during an initial visit.  With a good first treatment it only took 6 minutes per unit, and an average of 494 grams of bait, on a 14-day followup visit.
      The take home lesson from Miller's research is that pest control companies can't just go through the motions of baiting to get control of out-of-control cockroach infestations. Adequate time to survey, locate and treat cockroach harborages, as well as enough bait to manage the population is essential to a good treatment.  Miller's baiting formula (she used Advion and MaxForce Magnum gel baits) required 60 grams of gel bait per apartment when overnight trapping yielded more than 500 cockroaches, 30 grams for 100-500 cockroaches, and at least 15 grams for 50-100 cockroaches. AgriSense Lowline traps were used for all monitoring in the study.
• The BASF folks generated food for thought with several studies of their products including two Phantom formulations, Alpine dust, and their pyrethrins aerosol, HydroPy. Jason Meyers reported that 4-month aged residues of Phantom SC, and 180 day aged deposits of Alpine dust, performed as well at controlling bed bugs as fresh deposits of the insecticides. Such long residual deposits are unusual in pest control, making it necessary for frequent re-treatments to prevent pest reestablishment.
       With this data in hand, Meyers made a case for what BASF will be calling proactive bed bug control.  Because of Phantom's long residual, the company is conducting field tests to see whether two proactive (=preventive) treatments a year can keep bed bugs from establishing in hotel rooms.  Treatments of Phantom aerosol are applied twice a year to bed frames/head board and luggage rack.  Alpine dust is used once a year and applied to hotel room box springs, electrical outlets, carpet edges, baseboards, picture frames, electronics and sofas/chairs.  So far no new infestations have occurred in a Kansas hotel being used as a proof-of-concept site.  Expect to hear a lot of discussion about whether this approach can be justified as IPM, and whether it works sufficiently well to write preventative contracts for bed bugs in hotels. According to Orkin entomologist Ron Harrison, Orkin is one large company that expects to do more proactive bed bug control with its hotel customers in the future.
• Standardized assay methods for testing insecticides for bed bug control are a hot topic right now with regulators. One of the points of contention is which bed bug strain(s) to use. Bed bugs vary wildly in their susceptibility to insecticides.  Currently it is possible to pick a strain, like the almost completely susceptible Harlan strain, that will make nearly every insecticide look like a winner. But, according to Mike Potter of the University of Kentucky, 88% of bed bug populations tested from 110 sites around the U.S., had at least one type of resistance to insecticides.  Hence testing products against only the susceptible strains is nearly meaningless as a predictor of real-world effectiveness. But which strain or strains to use? It turns out that even the search for the perfect test strain is a moving target. According to Sumiko De La Vega, of Sierra Research Labs, even insecticide resistant strains lose their toughness after a few years in laboratory colonies.  One of Sierra's standard colony types lost most of its 2000-fold permethrin resistance over a 2-4 year period of no exposure to pyrethroid insecticides.  Frequent resistance testing may eventually become necessary for the performance of insecticide testing with bed bugs, making such tests more difficult and expensive.
• Some of you may have wondered what happens to insecticide residues that are exposed to the high temperatures of heat treatments for bed bugs.  Apparently heat is not that destructive to residues of many of the commonly used bed bug materials. Temprid, Transport, Phantom SC, Phantom aerosol and a Phantom+IGR experimental formulation showed no loss in efficacy after 7 hours at 135 degrees F, according to PhD student Margie Lenhert from Clemson University.
• More of us may be providing dinner for bed bugs than we realize, according to an Orkin in-house study conducted by Ron Harrison.  Harrison noted that early research conducted 50+ years ago suggested that perhaps over 80% of people showed some kind of reaction to bed bug bites. However, his informal study, using over 1400 Orkin company volunteers, showed that only 3.8% reacted quickly to bed bug bites. Only 1.1% showed any delayed (4 days or more) reaction.  If these numbers are accurate, the number of biting cases in hotels may be substantially under-reported.  In addition, lack of skin reaction in many people could explain why many customers who report infestations wait until bed bugs reach high numbers in a home or an apartment.
•  

  

  NPMA graphic illustrating words that people use when
  asked what comes to mind when they hear the name
  "bed bug". The larger and bolder the word, the more
  common the response (graphic courtesy Jim Fredericks).

  Jim Fredericks of the National Pest Management Association reported on new online bed bug resources.  Allthingsbedbugs.org is a new consumer oriented site published by NPMA.  Its best management practices tab, however, would be a good place to compare your company's practices to see how they hold up to industry standards.
• Rick Cooper, graduate student at Rutgers University, attempted to conduct field evaluations of bed bug sniffing dogs.  He noted that previous canine detection research reported in 2008 showed that dogs were capable of relatively high (95-98%) detection rates (correctly pointing out all bed bugs) and relatively low false positive rates (approximately 3% of the time dogs pointed to bed bugs that weren't there).  Cooper pointed out that the 2008 study was conducted under controlled conditions with planted bed bugs.  His study was conducted in real apartments, where bed bug infestation sites were well-known from previous, thorough checks by trained inspectors.  In one of his trials, he worked with 11 companies that claimed 95-98% detection rates (generalizing based on the published 2008 results).  In Cooper's study, actual detection rates in 48 apartment units averaged only 50% (ranging from 10-83%) for these companies, and the average number of false positives was about 20% (ranging from 0-43%). Even narrrowing the trial to his best, most experienced, teams, he was unable to replicate the high success rates of the controlled studies. Despite his respect for canine detection, he concluded that canine accuracy rates in the field are likely much less than what most canine handlers advertise, and that false alerts are higher in rooms with past history of bed bugs.  
       False positives are undoubtedly costing the public lots of money.  In a widely publicized bed bug infestation at the University of Nebraska, dogs used to inspect campus dorm rooms alerted in 197 of the 3256 rooms.  Evidence of bed bug infestations, however, were found in only 10 of the 197 rooms. Because of the publicity, and high public profile of the effort, all 197 rooms were treated, at a cost to the University of $400,000.  According to Cooper, the philosophy about canine detection is changing. In the past it was "trust the dog"; today, it's "check the alert" (with a visual inspection).

Strategically placed Plexiglas cutouts show trainees at the
Orkin house, normally out-of-site construction features
important to pest control, such as this bathtub plumbing. 

In addition to hours of Powerpoint slide shows, participants in the NCUE conference were treated to a field trip to the Orkin University and Training Center. The facility is very impressive with mock kitchens and grocery stores, numerous outdoor termite treatment training stations, and the Orkin House, a full sized home with numerous examples of pests, pest damage and structural cut-aways to show how homes are constructed and how insecticide treatments might interact with a building.  One of the highlights of the tour, for at least a few of us entomologists, was searching for the infamous kudzu bug on the kudzu vines so common in the Atlanta area.