Moving Beyond Mallis: Young Entomologists at NCUE

The biannual National Conference on Urban Entomology (NCUE) is always a treat.  It’s a relatively small conference with a personal feel. Many attendees know each other personally, and new students get to learn more about urban entomology outside their labs and classrooms. This year’s meeting in Raleigh, NC attracted about 200 students, university faculty and industry urban entomologists, including a score of researchers from the joint invasive pest ant conference.

When I attend NCUE I see folks whose lives and careers I’ve followed for many years, as well as new faces who are the future of our industry.  I hear controversy in discussion sessions as researchers politely prod speakers to think more deeply about their research results (entomologists are almost always polite); and sometimes I hear talks that will change the way I view structural pest control. While there were no real revelations at this meeting, many of the talks I heard this year fell into the category of “baby steps” toward better pest control and deeper understanding of the biology of structural pests.

Every NCUE meeting has a Distinguished Achievement Award recipient. This year’s honor went to Brian Forschler, a respected termite researcher from the University of Georgia. It was his job to open the meeting with a tribute to Arnold Mallis, who many of you know by his “ten-pound” Handbook of Pest Control. 

In the 1940s and 50s Arnold Mallis was a
rising star in the field of urban entomology.

Forschler noted that Mallis filled a desperate need at the time for science-based information on household insect pests. Though he had little to say about IPM (the concept hadn’t been formally proposed), in his books he summarized critical biological information upon which IPM programs could later be built. Mallis taught us that urban entomology is built upon a firm foundation of education and engagement with its stakeholders. Forschler urged each attendee, especially each student, to consider new ways to engage outsiders with urban entomology, while being the same consummate entomologist, naturalist and observer of insects as Arnold Mallis.

After Forschler’s session, the meeting began with papers from student award winners.  When I listen to students I always keep in mind that today’s students are tomorrow’s experts.  In just a few years these will be the folks making the rounds at CEU meetings for NPMA and other professional gatherings, so it pays to listen and make note of the new faces.

Emily Vernon, Bachelor of Science Student Award winner came from North Carolina State University where she studies Blattabacterium, a genus of symbiotic bacteria that live within special bacteria-hosting cells of cockroaches. These bacteria, she proposed, are essential to the German cockroach’s ability to survive in nitrogen-poor environments. In her research with 16S ribosomal RNA primers she detected high levels of variability in Blattabacterium in field populations of cockroaches, leading her to pose the question: “if we can manipulate Blattabacterium in the cockroach, might we be able to control cockroaches in the field?” I don’t know the answer, but I do know that when I was her age my most profound questions dealt with where to go for pizza on Friday night. Wow!

Master’s Student Award winner, Danielle Hoefele, Simon Fraser University, tackled a whole new structural pest, the European fire ant, Myrmica rubra. Think of it as a fire ant for the north.  The European fire ant is spreading into British Columbia and Washington State, as well as New England and eastern Canada.  It’s an aggressive ant with a sting that itches up to 10 days.  Danielle looked for different food sources that might work well in a fire ant bait. She found that baits combining carbohydrates and proteins were most attractive. Ultimately, she hopes to design a custom bait to provide a much-needed control option for this pest.

The herb thyme is a natural source for the monoterpene oil,
thymol, which has promise as a natural insecticide against
bed bugs. Relatively few plant oils have been investigated for
use in urban entomology. 

Sudip Gaire from Purdue University was the Ph.D. Student Award winner for his studies on the effects of plant essential oils against bed bugs. Sudip is pursuing more effective, safer, natural insecticides for bed bugs.  By looking at plant essential oils that have not previously been tested, he hopes to discover better options for controlling insecticide-resistant bed bugs.  He found carvacol, thymol, and citronellic acid to have to be the most toxic plant oils, none of which is currently in use against bed bugs. It may be years before these products are successfully brought to market, but Sudip is starting the process, and he reminded me that the field of essential oils for pest control is ripe for mining.

In another student paper, Sanjay Basnet from the University of Nebraska, is looking at ways to turn the bed bug’s own genetic material against itself. Interference RNA, or RNAi, are small RNA strings found naturally in the cell that help block expression of target genes. A few years back, someone got the bright idea that if we could find the right RNAi strings we might be able to use them as insecticides to turn off genes that are critical for an insect’s survival or reproduction. Sanjay thinks he may have found such an RNAi strand—one that can reduce egg production in bed bugs.  When injected into bed bugs this natural and biodegradable molecule reduced average daily egg production from 6/day to 0/day at 3 and 4 weeks after treatment. Much more work is needed to bring this kind of technology to your company; but its always encouraging to hear about any progress in this area.

One of today's rising stars of urban entomology is Zach DeVries, PhD student at North Carolina State under major professor Coby Schal.  DeVries is looking at a previously ignored component of bed bug aggregation pheromone called histamine.  You’ve probably heard of histamine. It’s an important chemical that our bodies produce to regulate our local immune response. On the positive side, histamine allows capillaries to become more permeable to our white blood cells so they can engage pathogens during an infection.  On the downside, it’s the chemical that causes inflammation and itching after an insect bite or exposure to an allergen. That’s why you may take an antihistamine drug for a runny nose or itchy eyes. Histamine also affects numerous organs, causes increases in heartrate, and difficulty breathing.

DeVries and colleagues inspected house dust from homes with and without bed bugs. They found up to 25X higher levels of histamine in bed bug-infested homes. They also found that histamine persisted for 3-6 months after an infestation had been eliminated. Whether these relatively low levels of histamine associated with bed bugs will have chronic effects on human health is unknown. But if significant, DeVries’ team’s discovery could be as important to pest control as the discovery of the link between German cockroaches and asthma in the 1990s.

DeVries also gave a second, more controversial, paper on progress towards developing a liquid bait for bed bugs. He suggests that liquid baits might offer an alternative insecticide-delivery method that could bypass at least one of the resistance strategies used by bed bugs (such as thickened, pesticide resistant cuticles).  So far, De Vries has identified good active ingredients (such as fipronil, neonicotinoids, and DMSO) for such a bait.  The feeding attractant for bed bugs is more of a challenge, however. Bed bugs eat blood of course, which is not likely to be stable in a bait formulation. And who wants blood-filled bait stations around their home?  He found that simple salt water, with or without the natural cellular compound adenosine triphosphate (ATP), made an attractive feeding stimulant for bed bugs.  The challenge, he argues, is to come up with a way to deliver this tasty insecticide to hungry bed bugs.  

But some listeners gently challenged DeVries to demonstrate how baiting might be more effective than a good trap, say.  The reason that most cockroach, termite and ant baits are so effective, is that they don’t just kill the individuals that come to the bait. They are effective because they kill the feeders and their companions. This happens when other cockroaches eat the feces or dead bodies of bait-fed cockroaches, or when ants and termites share their toxic meals with nestmates. At this point it’s hard to see how you might get secondary kill with bed bugs. Time will tell whether NCSU researchers will demonstrate the practicality of blood-mimicking bait stations; but it’s a thought provoking idea, and I’m glad someone is exploring it.

Whew. That was just some of what I learned from students at NCUE last month.  In my next installment, I’ll cover some of the highlights from veteran urban entomologists in Raleigh. 

Benefits of cockroach control

Before starting graduate school in entomology I worked as a pest control technician out of college. My accounts included a sprawling, multi-story public housing complex in Seattle, WA. These visits were frustrating to me, because of the difficulty (impossibility) of putting much of a dent in the well entrenched German cockroach population that scurried back and forth among these apartments.

One of my visits, however, was the home of a single mom. It was a short encounter, and I'm not sure I ever saw her again; but I'll never forget the mother's gratitude for my efforts to battle the cockroaches plaguing her and her daughter.  The woman's apartment, unlike many in the community, was uncluttered and very clean. It was obvious she was doing her part to keep cockroaches at bay, something that made my job a lot easier and more effective. Despite the feeling that I wasn't putting much of a dent in the overall cockroach problem in those apartments, I went home that night feeling a little better about my job in pest control.

Improved technology

Two major changes have occurred in cockroach control since the early 1980s.  First, we've learned a lot more about the health impacts of cockroaches over the past 25 years. Besides being unsanitary and capable of spreading disease pathogens, we now have solid evidence to show that cockroaches are major contributors to asthma morbidity, especially among children living in infested homes.  Indeed, the feces and shed exoskeletons of cockroaches have proved to be among the most important indoor asthma causes we know of.  Children who grow up in cockroach infested apartments have higher rates of asthma, more missed school days, and more doctor visits than do their more affluent classmates from cockroach-free homes.

Second, with the discovery of effective baits, we have much better tools for cockroach control today. The insecticides available to me in 1980 were mostly residual sprays and dusts that had to be applied directly to cockroach hiding places.  If counter-tops were not cleared and covered, or cupboards not emptied before I arrived, there was little I could safely do with my Ficam®, diazinon and malathion sprays and dusts.  In addition, many of these sprays were repellent to cockroaches, something that I learned later in grad school greatly reduces their effectiveness against insecticide-avoiding cockroaches.

Today pest management professionals and even homeowners have access to technologies that are safer and vastly superior to the old insecticides.  Containerized and gel baits, in particular, have revolutionized our industry's ability to manage cockroaches.  Although sanitation is still important for cockroach IPM, baits have shown an ability to suppress cockroach numbers even in cluttered and poorly maintained living quarters.

A number of studies have shown over the past 20 years that cockroach control and sanitation efforts could significantly reduce the quantity of cockroach allergens in apartments.  Indeed, the National Asthma Education and Prevention Program recommends reducing cockroach exposure as a critical step to take in reducing asthma risk.

Research news

A new study in the Journal of Allergy and Clinical Immunology out this week is the first to show that cockroach baiting by itself can result in measurable improvements in the health of children. The researchers looked at the apartments of 102 children (aged 5-17 years), all of whose homes had some level of cockroach infestation.  Half of the children were assigned to homes that would be treated by researchers with cockroach baits, and half of the homes were left untreated by researchers.  All of the homes were sampled for cockroaches using Victor® Roach Pheromone Traps, and health indicators were measured for all the children (such as number of school days missed, medication used, days of wheezing, number of nights where children woke up, etc.).

Treatment of homes consisted of placing either Maxforce® FC Magnum, or Advion® cockroach bait gels in areas with evidence of active cockroach infestation.  Those who put out the bait were not trained PMPs, but were research staffers instructed to place baits in the back corners of kitchen cabinets, behind kitchen appliances, and inside bathroom vanities.  No other control methods were used.

The median cockroach numbers were significantly lower in treated homes vs. untreated. By the end of the study none of the baited homes had evidence of cockroach activity, compared to a 20% infestation rate of the untreated homes.

Interesting to me was that after the study began cockroach numbers in the untreated homes went from 100% infested to only 20% infested.  The authors of the study attributed the drop in untreated homes to "study effects".  People whose homes did not get treated, but were being monitored for cockroaches, took extra pains to clean up before the research team arrived, and they conducted additional cockroach control on their own, apart from insecticide baits applied by the researchers. This lead to an almost 85% reduction in trapped cockroach numbers in the control homes.

So it's even more remarkable that, despite the cockroach reductions in homes not receiving bait treatment, researchers still noted significantly better cockroach suppression with bait-treated homes and significant improvements in children's health.  In treated homes, for example, children had 47 fewer days a year with asthma symptoms compared to homes that were not treated with baits. Children in treated homes also had improved lung function and significantly fewer doctor visits compared to untreated homes, despite the relatively small sample size and relatively low cockroach levels in untreated homes.

These results should be carefully noted by the pest control industry.  With readily available, high-quality cockroach baits, and relatively easily taught skills, pest control technicians today can make a significant impact on the health and well-being of customers. In fact, I'm sure that the benefits of a highly skilled technician applying baits would accrue even faster and be more significant compared to untrained applicators.

When I consider how far cockroach control has come since my days with a B&G sprayer, these results are truly amazing.

I've said it before, and will say it again: the work you do as a PMP is very important.  Cockroach management in multifamily housing may not be very glamorous, but few other accounts provide the opportunity to better your customers' lives more.  And that's something that should make you feel even better when you go home at night.

Highlights of NCUE

Albuquerque, NM was a beautiful (and tasty)
location for this year's NCUE meeting.

One of the first professional meetings I attended as a newly minted PhD entomologist was the National Conference of Urban Entomology. Held that year in College Park, Maryland, the meeting was a revelation.  Finally, I thought to myself, a gathering of people who understand what I do for a living--like a Cheers bar for entomologists!

We've all been to parties and been asked what we do for a living. Answer that you're "an entomologist who specializes in structural insect pests", and if you're lucky you'll get a wan smile. Rarely does anyone get it. Not so at the National Conference of Urban Entomology. The NCUE is a gathering of very friendly, slightly nerdy, science-oriented people who love to talk about urban insects and pest control.  No one in this group needs bother with common names when discussing Periplaneta americana, or Coptotermes formosanus. Talks like "Gut bacteria mediate aggregation in the German cockroach" are guaranteed to draw a crowd.

This year's NCUE meeting was held in Albuquerque, NM, and it did not disappoint.  Besides a short, but packed agenda of buggy stuff, Albuquerque was a wonderful place to meet.  Not a whiff of Breaking Bad drug labs, but lots of clear skies, mountain and desert views, and great New Mexican cuisine. (Oh, and The Donald was even in town one night!)

To give you an idea about what all of us bug scientists talked about in the sessions and hallways this week, here are some of my notes to self:

• Pest exclusion was the dominant topic for one session and was revisited throughout the meeting.  Imagine if homes and offices could be designed to keep pests out, or at least make them uncomfortable.  Dr. Jody Gangloff-Kaufman from the New York State IPM Program talked about two relatively new working groups dedicated to promoting better building standards to resist pests.  They call their project SCOPE (Scientific Coalition of Pest Exclusion), and the two groups focus on residential and commercial buildings, respectively.  The group has been meeting for approximately 2 years and has about 120 members.  Goals are to assemble a database of literature that supports pest exclusion (PE) concepts, and to provide checklists for builders and architects to promote better PE. A bit of controversy arose when a session speaker suggested that perhaps the typical pest control business model would not willingly embrace pest-resistant buildings. A PMP participant objected saying that offering pest proofing was an important part of their business model and how their company remained competitive.
• Dr. Chris Geiger, with the City of San Francisco, spoke about how IPM and PE principles have influenced the LEED (Leadership in Energy and Environmental Design) program. LEED remains one of the most influential and successful certification programs ever, contributing $80.6 billion to GDP between 2011-2014 and changing the way architects design modern buildings. Dr. Geiger noted that 59% of LEED-for-existing-buildings applications take advantage of points for having an IPM program in place.
       Although LEED recognizes the importance of IPM to environmentally sound construction and maintenance of buildings, it has not provided strong leadership on pest exclusion. Consequently, in 2013 Geiger led a group to produce a guidance document for architects and builders to provide specific examples of how to make buildings more pest resistant.  These guidelines are being put to work in some major public housing renovations in San Francisco, and have been offered to builders as a standard to reference when trying to achieve IPM points in LEED projects.
       Dr. Geiger hopes to update these guidelines this year, and is actively seeking experts in pest control, engineering, entomology, and architecture to be a part of the process.  If you are interested in joining his group, go to this web form to add yourself to the list of participants.
• Dr. Tim Husen with Rollins Corporation suggested that PMPs needing fast access to a listing of low toxicity products acceptable to LEED certifiers can use a mobile phone app called PestSmart, available through the Pesticide Research Institute. I found and downloaded this free app quickly on the App Store for my iPhone.  The listing is based on criteria used by the City of San Francisco in their (now extinct) Tier III list of low toxicity pesticides.  This famed list is no longer supported or updated by the City of SF, but is still sometimes referenced by architects, especially under the now dated, V3 (2009) LEED credits.  Keep in mind that the PestSmart app provides an assessment of likely toxicity, but does not take into account risk of exposure, an important component of hazard (toxicity X exposure = hazard).  
• Famed "rodentologist," Dr. Bobby Corrigan, also spoke on rat exclusion, and provided a case history from the National Park Service's African Burial Ground Monument.  A highly sensitive, historically significant site in New York City, the property was heavily rodent infested prior to Corrigan's consultation.  Xcluder Geo Mesh was installed under sod at the site, and burrows were gassed with dry ice (2 lbs per burrow system) to successfully rid the property of these "diabolically clever" pests, as Corrigan described them. Though initially more expensive, Corrigan believes the use of CO2 and advanced mesh barriers like this could be very useful for eradicating rodents from sensitive locations.
• Not surprisingly, mosquitoes were a hot topic of discussion this year. PMPs are beginning to shift their company business models to include mosquito control. Orkin's Dr. Ron Harrison noted that mosquitoes are his company's number 1 annual service offering. Rick Bell, with Arrow Exterminating, reported that his company's mosquito revenue has gone from $39,000 in 2004 to $6.5 million in 2015, all with little reliance on automated backyard mosquito misting systems.  He noted that Arrow's mosquito control customers are among their most loyal, with a 92% annual retention rate. 
• Dr. Joe Barile of Bayer Environmental Science cautioned the industry about how mosquito control is marketed. He recommended use of the term "nuisance abatement" rather than any language that implied disease elimination or protection from mosquito borne disease.
• Dr. Grayson Brown from the University of Kentucky summarized some of the latest promising technologies for residential mosquito control. He reported that the Innovative Vector Control Consortium (IVCC), a group founded over 10 years ago to seek solutions to mosquito borne disease, is currently evaluating 9 new classes of active ingredients for vector control. If even a few of these insecticides prove safe and effective, it could revolutionize adult mosquito control. He also noted that essential oils are also receiving more study as insecticides, repellents and excitatory agents to enhance the effectiveness of other products.
• Although it appears that most pest control companies rely largely on barrier sprays as a core of their mosquito control programs, pollinator and beneficial insect concerns are an issue. Consequently, there is much interest in alternatives to backyard sprays for mosquito control. Among the promising alternatives, according to Brown, are autocidal gravid oviposition (AGO) traps.  These are artificial breeding sites for Aedes mosquitoes which trap, kill, contaminate or sterilize any female mosquito lured in to lay eggs.  In one study in Puerto Rico, 3-4 large AGO sticky traps per yard were sufficient to reduce Aedes mosquito populations 53-70% and prevented mosquito outbreaks following rain in 81% of homes. 
• Pyriproxyfen, the insect growth regulator in Archer® and Nygard® insecticides, is also being tested as an active ingredient in some autocidal traps.  Research suggests that besides killing their mosquito offspring before they emerge from treated water or cups, pyriproxyfen residues in these traps transfer via the mosquito herself to other breeding sites through a process called auto-dissemination. This is one of the coolest and most selective mosquito controls I've heard of.  If proven in the field, a PMP or homeowner, could put a few gravid traps out in the yard for minimal cost and get season long mosquito suppression with no risk to bees, butterflies or other beneficial insects.  In combination with sprays and other control methods, it might be possible to achieve a high level of control and reclaim mosquito infested backyards with minimal harm to good bugs. Currently few lethal ovitraps are commercially available; but watch for new products to enter the market soon.
• No gathering of urban entomologists would be complete without a few papers on bed bugs. Though the number of bed bug papers was down this year, those presented were oriented towards the practical.  Three papers came from Virginia Tech.  Dr. Dini Miller presented on bed bug vacuums. She found that all the battery powered vacuums she tested (several Black and Decker, and Dyson models) were surprisingly effective at removing adults, nymphs, exuviae and eggs. Besides offering a cleaner and more allergen free environment, it is notable that vacuums remove the exuvia (cast skins) of bed bugs.  This is important for control, she noted, as cast skins may be used by bed bug nymphs as a refuge from sprays.  She also recommended using disposable, knee high, nylon stockings over the mouth of your vacuum (which she colorfully called "condoms for your vacuum") to isolate your catches and reduce the risk of bringing bed bugs back to the office.
• Katlyn Amos, graduate student at VT, tested two multi-action insecticides against pyrethroid resistant bed bugs.  Both Tandem and Crossfire, a new product from MGK, performed well against these resistant bugs. 
• Molly Stedfast reported on mattress encasements for bed bugs.  One of her most important findings was that not all bed bug encasements were bite-proof. After stretching encasement fabric over the mouths of glass jars filled with bed bugs, and applying the fabric-covered mouths to the arms and legs of volunteers, many of the bed bugs were able to successfully feed. But as Stedfast noted, bite resistance is not an issue for box springs.  Nor may it be that critical for bed mattresses either.  Bed bug mouthparts are only about 1 mm long, so once covered with a mattress protector and sheet, the average sleeper should be well protected from any bed bugs trapped in a tight encasement.  Tight zippers and rip resistance are probably more important features when selecting an encasement. 
• In the category of really-interesting-science-that-may-not-have-an-immediate-application, Dr. Rachel Adams, University of California-Berkeley, talked about the microbial diversity of homes.  The ability of science now to take DNA swabs and identify 40 microbes from one's forehead has rapidly progressed from my college microbiology class where "cutting edge" meant plating out and isolating a few microbe colonies on Petri dishes. This new technology means we can now isolate hundreds or thousands of fungi and bacterial DNA from the average home. The challenge we have today is understanding what these microbes are doing.  Are they reproducing, or just there because they floated in from outdoors?  And what are their human health impacts, if any? We know that microbes can positively or negatively affect our health, allergies and possibly ability to ward off disease.  One example Dr. Adams gave was the so-called 'farm effect', where children who grow up exposed to bacteria associated with cows and manure have asthma rates as much as 4X lower than urban-raised children. Insects may play a role in delivery of some of these microbes, good or bad, into homes.
• Finally,  Dr. Coby Schal, one of the most interesting and creative urban entomology researchers in the country today, spoke about the gut bacteria in German cockroaches (Blatella germanica to us entomologists!). His research has shown that it may be bacteria that are responsible for much of cockroach aggregation behavior.  Cockroaches with their full gut bacterial complement grew up faster, reproduced faster, found mates faster, and were more efficient foragers compared to cockroaches without their gut microbes.  In addition, cockroaches were more attracted to the poop of other cockroaches with buggy guts, suggesting that these microbes might hold the key to developing a better cockroach attractant for trapping and control purposes. And you might be surprised how much cockroach feces humans are exposed to. A colony of 1,000 German cockroaches (a moderate infestation in some restaurants and apartments) produces an estimated 5 grams of feces per night, or nearly 2 Kg (4 lbs) of feces a year. These same feces contain 7.5 million units of Bla-g antigens, which can cause allergies or asthma in humans in amounts as little as 8 units.

Now you know what urban entomologists talk about when they get together. The subject matter may be boring, humorous or even distasteful to the average person; but be thankful that someone is interested in this stuff.  As for me, I'm glad there's at least one place where everyone knows my name. Cheers!