Friday, January 13, 2017

Spring IPM Seminar in Dallas Next Month

Continuing education doesn't have to be a painful experience.
Last fall's IPM Seminar attracted nearly 400 applicators.
If you're a pesticide applicator in need of CEUs this year, I have some good news: no more yellow chairs.  For years, pesticide applicators have come faithfully to the Texas A&M AgriLife Center in Dallas for continuing education training.  And for years one of the consistent evaluation remarks we've received is that we need to "do something about" the hard, 1960's era Fiberglas chairs.

Starting next month we're no longer going to be sitting in those chairs for pesticide training. Instead, this spring the IPM seminars will be moving off campus to the nearby Richardson Civic Center.

The 2017 Spring IPM Seminar is scheduled for Thursday, February 23.  We have an excellent line-up of speakers, and offer a good lunch.  Cost will remain the same for 2017.

To register for the 2017 event, go online to http://agriliferegister.tamu.edu/IPM.

For a copy of the program, including directions to our new location, click here. This year's speakers and topics include:
  • Michael Kelly, with the Structural Pest Control Service/TDA in Austin, will speak on Pesticide Rules: What's new and what it means to you.
  • Sam Kieschnick, with Texas Parks and Wildlife in Dallas.  Urban Wildlife, including biology and behavior of bobcats and other troublesome mammals.
  • Dr. Casey Reynolds, Texas A&M AgriLife Extension Service, will talk on Herbicide Selection, including understanding how different herbicides work, and how to select the best product for your needs.
  • Doug Van Gundy, Zoecon/Central Life Sciences, will talk about Pesticide formulations and their uses, also important for selecting the right product.
  • I will speak on Control strategies for the crapemyrtle bark scale, an important and difficult to control pest of the most common flowering shrub in north Texas.
If you attend, I can't guarantee that the new chairs will be any better (they won't be any more durable). The new facilities, however, will be great. We'll have more space, in a more comfortable environment, and bigger screens.  I believe you'll appreciate the change.

Wednesday, January 4, 2017

Rabies and the PMP

Last August I was out for an early morning run when a stray dog rushed me from an alleyway and knocked me down.  In light of other dog attacks in Dallas last summer, at least one of which was fatal, I feared the worst as the dog clamped onto my ankle.  But as soon as I recovered my wits enough to defend myself, the dog was off.  The whole incident probably took no more than five seconds.

Bonnie and Clyde. The dog on the left bit me in August and is still on the
loose. 
Uncollared, stray dogs are a rabies and public health risk, and should be 
reported to animal control. PMPs who encounter stray dogs or work with
wildlife should consider getting the rabies vaccine series. Photo

courtesy Plano Animal Services. 
Thus began my education about rabies and rabies vaccinations.  I've known a long time about the seriousness of the rabies virus: how when it takes hold of its victim it is almost certainly fatal; how a victim's last days are spent in convulsions, wanting and needing water but unable to swallow due to spasms of the voicebox; and how death from respiratory failure usually takes place within 3-5 days of when symptoms begin.

Although my bite was shallow, I knew enough about rabies to realize I shouldn't ignore it.  On the other hand, I wanted to make sure I really needed the shots (I hate shots).  I learned within a few days that the same dog had been responsible for biting others in my community, and that the local animal control was working hard to catch it and its partner. I hoped that perhaps the animal would be caught and would test negative.  In fact, several days after the attack I spoke to the head of animal control in our town who was very familiar with these criminal dogs. He told me that in his opinion, given their behavior, they were likely not rabid. He explained that almost always a dog that has become infectious will show symptoms of rabies including abnormal behavior, partial paralysis, or lethargy within five days.

At this point I had a big advantage of knowing someone in the Texas Department of State Health Services.  Dr. Shelly Stonecipher, at my local DSHS regional office was very helpful, answering my questions for over an hour, and advising me that the emergency room was probably my best, and most affordable, option.  My county health department, I was told, should have the necessary vaccines on hand, but would not take insurance and would have to charge the full wholesale cost of the vaccines.  This was my first big shock.  The health department cost for the first shot alone would likely be around $2,000.  The emergency room would be more expensive, but at least it would be covered by my health insurance.

Dr. Stonecipher explained that post-exposure treatment of rabies is very effective, but to work it needs to be given before symptoms occur (some sources say vaccination should take place within 1-6 days, other sources 10 days or more...a disturbingly loose margin of error). The treatment consists of five shots.  The first shot, called the human rabies immune-globulin shot, is given only if a bite has taken place and infection possibly already occurred.  The purpose of this shot is to confer rapid, though shorter lived immunity to the rabies vaccine.  This was the most uncomfortable of the injections, though not as bad as what I was told rabies shots used to be like (painful injections to the abdomen were the standard treatment up until the 1980s). I was told by my emergency room doctor that at least half of the 10 ml immune-globulin shot is supposed to be administered as close as possible to the site of the bite.

One online source says this shot should be given the day of the bite.  However, in my case, no one I talked to in the medical community seemed especially urgent about my getting the shot immediately. I thought I could wait up to 10 days, the quarantine time for some domestic animals.  This would, I'd hoped, buy some time for the dog to be caught [It never was caught and is still, six months later, on the loose in my community--our neighbors now refer to them darkly as Bonnie and Clyde].  As it was, I waited eight days; but if I had to do it over I probably would not have waited more than five days.

The next part of treatment is four rabies vaccine shots given in the arm--one the same day as the immune-globulin shot, and the others on days 3, 7 and 14 after the first shot.  Rabies vaccine confers longer term immunity via antibodies.  But the vaccine may not work quickly enough to prevent rabies if someone has already been bitten by a rabid animal. That's why these are given in combination with immune-globulin.

The vaccine shots were easy and painless compared to the monster immune-globulin shot.  This rabies vaccine series is what anyone wanting pre-exposure rabies prophylaxis would receive.  After getting my first immunization at the emergency room, I was told that the most affordable and convenient way to get the rest of the series was through one of the local clinics that specialize in vaccines for travelers. Luckily there was a Passport Health office near my workplace.  Also, I discovered that some hospitals carry rabies vaccine shots which you can get by making an appointment and thus avoiding the emergency room.

I was surprised by two things regarding my dog attack.  First, no one I spoke with seemed to care or really have strong opinions on when or whether to start the course of treatment. Some medical offices seemed not to know a lot about rabies treatment. Websites had conflicting information about virus incubation periods. In other words, I was on my own to figure out what to do about my health.

My second surprise was the cost.  Even with insurance, my out-of-pocket cost for the vaccine series alone was close to $1,000.  Even more appalling, the following month the bill from the hospital arrived.  The overall bill to myself and my insurance provider for an immune-globulin shot, first vaccine, and 15 minutes of an ER doctor's time, came to $10,179.  The itemized bill (which I had to request) listed the immune-globulin shot as the biggest expense, $8,318!  According to the hospital, after "discounts" and insurance contributions I personally still owed over $1,800.  All this to say, saving your life after a bite from a rabies infected animal is expensive--even with insurance. Estimates of cost of rabies post-exposure treatment on the Internet are highly variable, but my sticker-shock experience does not appear to be unique.

Advice for PMPs
Fortunately, human rabies cases and deaths in the U.S. are relatively rare, averaging 2-3 people a year.  This low rate is due to the wide use and effectiveness of the rabies vaccine, but it doesn't mean that precautions are unnecessary. The CDC recommends that veterinarians and staff, animal control and pest control professionals, spelunkers, and rabies laboratory workers be offered the rabies vaccine.  The vaccine should also be considered for any one whose activities bring them into frequent contact with potentially rabid animals, and for international travelers who might come in contact with rabid animals (treatment may not be readily accessible in all foreign areas).

My ten pieces of advice for anyone in the pest control industry concerned about rabies:
  • If bitten by a stray animal or any wildlife known to be a potential rabies carrier, don't ignore the bite. Talk to your personal or ER doctor to assess your risk, and determine whether you need treatment for rabies. Wash the wound site from any animal bite as soon as you can with soapy water and iodine based disinfectant. 
  • If possible, take steps to have the offending animal, like a bat, captured for testing. It could help you avoid expensive post-exposure prophylaxis. Care should be taken not to damage the head of the captured animal, as this may prevent laboratory testing for rabies. Your doctor or veterinarian, or in Texas any of the Department of State Health Services regional offices, can assist with instructions on how to submit an animal for testing. 
  • Don't attempt to feed wildlife or touch any stray or feral animal.  Use proper protective gear, including double plastic bags, when picking up dead animals. 
  • Make sure your own pets and livestock, including horses, dogs, cats and ferrets, are up-to-date on their rabies vaccines.  
  • If you work under conditions that bring you into close contact with bat roosts, do bat removal, or do urban wildlife control, getting the pre-exposure rabies vaccination series is highly recommended. It is much cheaper and easier than post-exposure treatment.
  • Even if you are pre-vaccinated, you may still require a series of two post-exposure vaccine boosters after a bite from a possibly rabid animal.  This is still much cheaper than post-exposure treatment. Check with your doctor.
  • When working around bats, bites sometimes go unnoticed. Bat bites may be extremely small and generally painless. ANY unprotected physical contact with a live bat puts you at risk for rabies--another good reason for rabies pre-exposure vaccine.
  • If you must handle a live bat, use thick leather wildlife gloves.  
  • If you must enter areas of large bat colonies consider wearing a fit-tested respirator. Rabies is thought to be contracted only through bites; however there is some circumstantial evidence that urine or feces might on occasion be capable of aerial transmission, especially in areas of dense bat numbers. 
  • If you've been bitten recently by a dog or other wildlife and not gotten the post-exposure treatment, consider getting it.  Rabies virus can incubate in humans quietly for months after exposure. Although ideally its best to start the shots very soon after the bite, the post exposure prophylaxis can be effective as long as it is given before symptoms appear.  

Given that Bonnie and Clyde are still healthy and on the loose in my town, I'm pretty sure that my emergency room visit and bills last summer were unnecessary.  But if it happened again, I wouldn't do anything differently, except possibly start my treatment earlier. The risk of rabies is nothing to take lightly, and I feel better knowing that I have a pre-exposure protection. 



Animals at risk for rabies
Rabies is found only in mammals, especially carnivores and bats.  Animals that can and do get rabies include:

  • Skunks are among the highest risk mammals, especially in the south. 
  • Raccoons are the most commonly infected wild animal in the eastern U.S.
  • Bats, have low levels of infection throughout the U.S.
  • Foxes, especially in the Southwest and eastern U.S. may be infected with rabies
  • Coyotes, are infected in rare cases
  • Unvaccinated dogs and cats can be infected with rabies. According to the CDC, dogs are responsible for 90% of human rabies exposures and 99% of human deaths from rabies worldwide.
Rodents and rabbits rarely get rabies--the woodchuck, Marmota monax, a rodent, is an exception. Other low risk animals include oppossums, armadillos, shrews, and prairie dogs. Livestock and horses can get rabies, and because of their close association with humans vaccination is recommended.

Wednesday, December 14, 2016

Not all presents under the Christmas tree are welcome

Don't be stumped by strange, long-legged bugs in customer
accounts this month.  Consider hitchhiking aphids or other
insects when a Christmas tree is in the house.
Photo by Mike Myers.
The last week in November and first three weeks in December are Christmas tree season in the U.S.  All over the country, excited families take to the nearest tree lot to pick a recently cut tree for home.  Some of these trees, however, come with more than just needles and flocking.

Giant conifer aphids in the genus Cinara, are among the most commonly encountered insects on fresh Christmas trees.  These aphids form colonies on trees outdoors.  Smaller colonies and lighter infestations are often missed by the tree farm, or by a bright-eyed family out on a U-cut adventure.

Conifer aphids are sometimes mistaken for ticks by horrified tree buyers.  But ticks have eight legs, and are not likely to be brought into a home on a tree.  Aphids are not harmful to people.  They feed only on plants and will not bite people.  Nor do they live long off a live tree, so your customer need not be concerned about them laying eggs on, or infesting, their ornaments.

Conifer aphids are more likely to be present on cut Christmas trees after a warm fall like this year. The warm weather encourages higher late season populations on trees.

Closeup of a Cinara aphid, one of the most common
Christmas tree pests.  Note the two short tubes (cornicles)
on the abdomen that help identify aphids. Photo by Tom
Murray, courtesy Bugguide.net
When introduced into a warm home after sitting in a cold tree lot, conifer aphids usually become active and many will move off the tree. Mike Myers, with Bizzy Bee Pest Control in Dallas, encountered a typical case today (inspiring this post). The insects had left the tree and were seen by his puzzled customer crawling over the fireplace, kitchen, and bathroom of a small apartment.

Insecticides are not necessary or desirable for control of conifer aphids or any other insects/mites on Christmas trees. If one of your customers brings home an infested tree and it has not been decorated, encourage them to take the tree outdoors, shake it well, and vacuum up as many of the bugs as possible.  Or better yet, return the tree to the lot for a replacement.  Be sure to inspect any new tree and pound the stump on the ground several times to check for live aphids before bringing it home.  

Take care not to mash conifer aphids on carpet or furnishings.  They will stain.

Other pests sometimes brought in on Christmas trees include other species of aphids or adelgids, spruce spider mites, and even praying mantid egg cases.  None of these are harmful, and either replacing the tree or vacuuming the offending bugs is usually sufficient.

And don't forget that firewood can be another source of insects, especially beetles, during the winter months.  A good preventive measure is to keep firewood outside until it is needed for a fire.

Luckily, none of these pests are especially common on live trees.  Nor should they discourage you or your customer from bringing a fresh cut tree indoors.  In my book the smell from a real Christmas tree more than makes up for the occasional arthropod hitchhiker.


Wednesday, December 7, 2016

Attic Safety

If you do pest control, few work sites can match the extremes of what you find in attics. Work in attics can be hot (or cold), difficult and dangerous if you’re not at the top of your game. Yet inspecting and servicing attics can be a critical aspect of pest control, especially for residential customers.  So in the spirit of keeping safe during the holidays, here are a few tips I've gathered for working in attics.
Having a stable work platform and maintaining three points of
contact when moving are essential for attic safety. (Photo by
JoistMate™) 

Scheduling. In Texas, heat may be the biggest safety challenge of all in attics. If possible, it's best to schedule any summer attic work for the morning. Afternoon attic temperatures in Texas in the summer can range from 120 to 180 degrees F– dangerously high. Most pest control inspections in attics will be relatively short, but if you have to spend any significant time in an attic, get an early start and make sure you have plenty of water and/or electrolyte drink handy.

Clothing. Proper clothing is needed to protect you from Fiberglas insulation, nails, hard objects and possibly bites and stings.  Long-sleeved shirt tucked into pants, safety glasses and bump hat are pretty important. Thick soled shoes or boots to protect against nails are highly recommended. And take it from someone with more than his fair share of bumped heads, if you don’t have a bump hat--any kind of cap or hat is better than none.

Safety Equipment.  Perhaps the most important attic safety gear is a respirator. A disposable NIOSH rated N-95 respirator (retains 95% of 0.3 micron-sized particles) is the minimal protection you need from short exposures to Fiberglas dust in attics. Cheap surgical masks are not sufficient here. If you suspect rodents are present, especially in rural homes where deer mice could be present, more sophisticated protection is needed. The CDC publishes recommendations for risk reduction when working in environments where hantavirus is a risk. For any PMP who removes deer mice from traps, or work closely with rodents, CDC recommends a half-face, tight-seal, respirator with N100 filter. If you have facial hair, like I do, or if you do not medically qualify to use a negative seal filter, you may need a (positive pressure) PAPR (powered air-purifying respirator), equipped with N-100 filters.  Expensive!

A fit-tested, half-face respirator with N-100 filters is the
minimum protection you should wear when working around
rodent droppings or other potential biohazards.
If you'll be handling dead animals in an attic, insulation or other vertebrate-pest contaminated materials, rubber, latex, vinyl or nitrile gloves are essential.  You will also need a sprayer or spray bottle to spray infested insulation or dead rodents with a 10% bleach solution, and two plastic bags to hold the dead animals.

Tools. Carry any loose tools you need in a tool bag that you can drag with you. Always set your tools aside in the tool bag rather than on a rafter and risk losing them among insulation. Bring a corded work light or backup flashlight with you. This will be important if you drop your primary flashlight, or if your primary light's battery fails.

A digital camera may be very useful for documenting what you find in the attic.

Getting Around. If you must travel from stable flooring onto joist beams, follow the rock climber's rule and maintain three points of contact at all times. Move only one foot or hand at a time, keeping your other feet and hands on a secure joist or rafter. Joistmate™ (see picture) is one commercially available platform designed to provide a stable platform for working on joists.

Take the advice of a PMP friend who fell through a ceiling many years ago, "never step blindly into insulation assuming a joist or floor decking will be there. If you cannot see the decking, beams or joists, DON’T STEP THERE. And don’t assume that all joists are on 16 inch centers. Twenty-four inches is more common in newer homes." He also advises everyone to be wary of beams or joists that might be damaged by termites or rot. They may not hold your weight.

It's a good idea to disturb insulation as little as possible to avoid stirring up dirt, dust, fibers and mold. Even when wearing a respirator, you'll want to minimize tracking contaminates down from the attic on clothing.  And if you see old vermiculite insulation, which if breathed can cause cancer, leave it alone.

Be Ready for Surprises. You are in the attic for pest control purposes, so be ready for pests! Keep a sharp eye open for signs of bee hives or wasp nests, or other pests like rats, bats, squirrels or raccoons. The possibility of being startled by encountering a scurrying pest is another good reason to have at least three good hand-holds or secure footing at all times. Always think about your escape route in case you encounter a wild animal.

Vaccines. In this business keeping up with your tetanus shots is a good idea, especially in a location where a sharp nail can appear where you least expect it.  If it's been more than 7 years, you need a booster shot.  And if you work in an area with bats, or where you commonly encounter wild (possibly rabid) animals like skunks or foxes, consider a rabies vaccine.  It is MUCH cheaper to get the rabies vaccine before you need it, than getting it after being exposed to the bite of a rabid or potentially rabid animal (personal experience here again, story for another post).

Ladders.  Falls from ladders are a leading cause of occupational death nationwide. If you use a ladder to access an attic, make sure it is firmly set up (75 degree angle is best) and rated for your weight. Don't descend a ladder face forward. Maintain that three point of contact rule and don't reach for items when ascending or descending. It's also a good idea to place plastic under the attic ladder, or be prepared to vacuum any insulation or debris that falls from the attic into the house.

Considering all the potential hazards working in attics, you might ask, "why bother?" Certainly anyone who manages urban wildlife, or does rodent control, knows that attic service is an essential part of their work.  But termite inspectors and PMPs doing general household pest control also have plenty of reasons to venture into attics or onto roofs. Let's promise ourselves that when we do, we'll put safety first.

If you have any memorable experiences, or safety tips for working in attics, I'd like to hear about them. We're in the process at A&M of putting together an attic servicing and safety curriculum as part of the new IPM Experience House. Your input could be an important addition to our training class. Contact me via the email link under my complete profile at right.


Saturday, November 19, 2016

Gleanings from ICE 2016

After an unintentional break in blogging due to a month of travel, I'm finally caught up enough to sit down with my notes and remember what it was all about.

If you can imagine thousands of entomologists swarming a convention center like fire ants on Cheetos, that's what it was like at the 25th International Congress of Entomology (ICE) held in Orlando, FL.  Held every three years, and rotating to a different nation every time, the ICE is the largest gathering of professional insect experts in the world--and this one may have been the biggest ever.  This year there were over 6,600 registrants from 102 countries, giving 5,396 presentations.

This was my first ICE, and it was overwhelming. It seemed like I spent half my week just sorting through the program to know which sessions and posters I should attend.  So probably like everyone who attends the ICE, I came away feeling like I had a unique, though very limited, perspective on the meeting.

One of the more enjoyable aspects of the Congress was meeting insect geeks from around the world. Some were bench scientists (who work in the laboratory), others worked in the field (including one enthusiastic fellow I met from Germany who brought his own dung on a field trip to trap Florida dung beetles--and it worked!).  There were first time visitors to the U.S., and many young and enthusiastic students. I met scientists from Finland, Vietnam, Australia, Kenya, and Iraq. But in the research sessions we were all just entomologists, despite different dress, language or customs.

So here are some highlights of my notes from the many hours of sitting in sessions and looking at PowerPoint slides:
  • German cockroach resistance to baits was the subject of a paper by NC State University researcher Jules Silverman. When comparing a susceptible German cockroach strain versus a field strain from Puerto Rico, his team found resistance to fipronil (15-20X), indoxacarb (15,000X) and even hydramethynon (350X). This was the first time hydramethylnon physiological resistance (as opposed to avoidance) has been found. Even with this resistance, in the lab they still saw complete control of cockroaches with gel baits.  But control was not as good in field trials where cockroaches had access to other foods.  My take home message was that we must be careful in our use of cockroach baits, and use them in combination with sanitation, sprays and other control tactics if we want to preserve them for coming years.
  • Paula Stigler Granados from the UT School of Public Health reported on the status of Chagas disease in the U.S.  Dr. Granados leads a task force studying the best way to protect human health from this important, disease transmitted by kissing bugs.  Doctors tend to downplay the risk of Chagas disease and rarely test for the disease.  Blood banks only test for Chagas if a person is a first time donor; hence some are concerned about the possibility of our U.S. blood supply becoming contaminated with the Chagas disease parasite. It's estimated that as many as 98-99% of cases in the U.S. remain undiagnosed.
          Educational awareness among doctors and patients will be a focus of the Texas Chagas task force, along with better screening, diagnosis and treatment.  Chagas is a chronic and ultimately fatal disease.  In previous years it was considered untreatable; but with a new drug therapy it now can be treated in earlier stages. Getting the drug to people who need it is still a challenge, however.
  • In related papers Dr. Gabe Hamer from Texas A&M reported on the results of a citizen science effort to study kissing bugs. From 2013 to 2015, they collected 2,812 bugs from 98 different Texas counties. The most common species detected was Triatoma gerstaeckeri, with 63% of those collected infected with the Chagas disease pathogen.  Another study by Rodion Gorchakov from the Baylor College of Medicine in Houston showed that humans are the most common host for kissing bugs collected by citizen scientists in Texas with human blood found in 66% of bugs.  So why not more Chagas disease in Texas and other parts of the U.S.?  The current theory is that gerstaeckeri and our other native kissing bug species are not very good at transmitting the disease during biting--something to be thankful for.
  • A couple of the more interesting and fun talks I attended were on insects and Japanese art and culture.  Some of you may know Dr. Nan Yao Su, developer of the Sentricon system concept at the University of Florida.  Turns out he is interested in insect influences on Japanese culture.  
  • Gunter Miller, from Hebrew University in Jerusalem, Israel, spoke on the process of developing effective attractive toxic sugar baits (ATSBs) for mosquito control.  Based on the fact that both male and female mosquitoes feed on natural sugar sources (like nectar, honeydew), ATSBs must be competitive with these natural sources, so the process of developing these baits is more complicated than just mixing sugar with a pesticide and spraying it on plants.  Their lab developed a "mosquito sangria" mixture (includes beer and Sangria) that will remain attractive to mosquitoes for more than a month after spraying.  Their technology is being used in the Terminix All Clear Mosquito Bait Spray.  This approach to mosquito control has attracted a lot of attention because of its potential to control some Aedes mosquitoes (vectors of Zika, and the most common daytime biters), and because of its need for less insecticide that might be harmful to beneficial insects.  
  • Joel Coats from Iowa State University has been studying alternatives to PBO, the most commonly used synergist for pyrethrins and other pyrethroid insecticides.  He found that many of the plant extracts he tested synergized permethrin as well or better than PBO, and many worked faster than PBO.  Apparently PBO was developed early as a standard synergist for the industry, and few people have taken the time to look at alternatives over the past 50 years. Having an organic synergist could be a real market boost to pyrethrins sprays, most of which cannot be sold as organic because of the synthetic PBO needed to make it effective.
  • According to MacKenzie Kjeldgaard of Texas A&M University, who analyzed ant gut contents with sophisticated DNA techniques, the fire ant's top food source was crickets, but also included springtails, caterpillars, flies and spiders.  
  • Freder Medina introduced a new BASF termiticide injection system using Termidor H.E.  The new application system uses 4000 psi pressure to inject the insecticide into the ground, eliminating the need for drenching.  The system will come with a base unit and mobile app to communicate with BASF.  You should be hearing more about this in 2017.
  • Last, I had a pleasant surprise in the commercial exhibits when I discovered a new book just published by Stephen Doggett, University of Sydney, Australia.  Stephen is a well known bed bug researcher, but had the genius to put out a handy photographic guide to bed bug infestations for, well, just about anyone.  It has dozens of excellent photos, tells where and how to spot bed bugs and what to do if you find bed bugs in your home. This should be a useful resource to share with pest control customers, and as a training tool for employees.  Self published, and not widely available, but you can get it at BioQuip books for about $7.
Of course there was much much more information at ICE this year, some of which I may incorporate in future posts.  But it's Saturday and time to get on to other activities. I hope some of this has been interesting and helpful.

Friday, August 5, 2016

Comparing dusts for bed bug control

For several years PMPs have known that dusts can be useful tools in the management of bed bugs, but a new paper in the Journal of Economic Entomology by Narinderpal Singh and colleagues at Rutgers University shows just how powerful they can be.

Singh et al. used four different lab assays and two strains of bed bugs to probe the efficacy of eight insecticide dusts.  Each assay showed a different aspect of how these dusts perform.  Together, I think, they do a pretty good job of evaluating how you can reasonably expect these products to perform in the real world.

Four experimental assays used to study the toxicity of
various dusts and predict their effectiveness in the field.
Clockwise from upper left (1) brief exposure assay, (2)
choice assay, (3) assay where CimeXa-treated bugs are
allowed to mingle with untreated bugs, and (4) continual
exposure assay with treated paper . (Singh et al. 2015,
J. Econ. Entomol.)
One of the problems with doing lab assays is that they can be highly unrealistic.  Sure, you can put an insect on a treated surface and watch them until they die (a continuous exposure assay).  Certainly this kind of assay can tell you whether there is potential for a product to work; but in a customer's home do your bed bugs have nothing better to do but sit on the insecticides you put out?  Probably not.

More often than not in the real world, insects run quickly across an insecticide barrier and then spend most of their time resting on untreated surfaces. Insecticide exposure may be only a matter of seconds. At other times, insects that move back to a treated harborage may be able to sense when they are on insecticide residues.  They may then choose to move to a clean spot that has not been sprayed or dusted (a sign of repellency).  Continuous exposure assays may overestimate the effectiveness of insecticide applications, especially when applications do not reach key harborage areas, or when residues are repellent to the pest.

On the flip side, insects may inadvertently pick up insecticide residue from a treated surface and carry that insecticide on their cuticle back to a harborage area. When this occurs they may transfer it via contact to other bed bugs clustered in the same harborage.  Failure to account for this in lab assays might end up underestimating the effectiveness of your treatment.  

Singh and colleagues tried to account for all of these possibilities in their research. One assay required the bugs to sit on treated paper for the length of the study.  A second assay had the bed bugs walk across a treated one-inch barrier.  And a third test gave the bugs the choice to visit and rest on either dust-treated or untreated surfaces.
Bed bug dusts included in the trial were Tempo, DeltaDust, Cynoff, Pyganic, EcoPCO D.X, Alpine, MotherEarth, and CimeXa. 

As you might expect, all products killed bed bugs when they sat continuously on the treated surfaces. After five days there was 100% mortality for all bed bugs in the treated dishes. When bed bugs were allowed to choose freely to rest on either treated and untreated surfaces, CimeXa and Tempo gave 80-95% control after one day; however after 10 days MotherEarth (diatomaceous earth) and Cynoff were close behind.  

The clear champion of the toughest test, the brief exposure test, was CimeXa Dust. CimeXa provided 95-100% mortality (at 1 and 10 days after exposure) to bed bugs crossing a one inch barrier of the dust.  Tempo was the next most effective product in the brief exposure trial, providing 40-60% mortality against the two bed bug strains. This ability to kill bed bugs with very short contact can be a game changer. It suggests that CimeXa may be capable of providing decent barrier protection on bed and furniture legs, in dressers or even along door thresholds (though unprotected deposits will likely be quickly rubbed or swept away). 

Singh and his team then went on to see whether CimeXa might also have the ability to transfer from exposed to unexposed bed bugs. It did. Clean bed bugs, that had not been previously exposed to CimeXa, when placed with CimeXa-treated bugs also had significantly higher (80-100%) mortality after 10 days compared to untreated controls.

Singh's work backs up previous work done by Mike Potter's lab in Kentucky.  Potter's group found that CimeXa was more effective than liquid Temprid residues against resistant bed bug strains in continuous exposure assays. He also found that as a stand alone treatment in infested apartments it provided rapid and marked control, superior to diatomaceous earth, and similar to that provided by the top liquid insecticide sprays. 

What these studies tell me is that insecticide dusts should definitely be part of your bed bug control program, especially in accounts with insecticide resistant bed bugs.  Silica aerogel, the active ingredient in CimeXa, performed better than the other commonly used desiccant (MotherEarth, i.e., diatomaceous earth), and even out performed the other pyrethroid dusts.  It should be noted, however, in settings where harborages can be fully dusted, these other products may still provide good control. And laboratory tests cannot fully duplicate what happens in the field--your real world accounts.

But my real reason to single out this study is that it provides a true low-risk option for bed bug control.  Because the mode of action of desiccant dusts is based on abrading the cuticle of the insect, and not on any mechanism that would potentially affect human health, it's a no-brainer to make these products a mainstay of your dust arsenal.  Used inside furniture, behind drawers and baseboards, in cracks and crevices of bed frames, these products make excellent, safe to use, treatments. Even if heat treatment is your tactic of choice, insecticide dusts can provide a long-term supplemental treatment to kill any bed bugs that might re-infest an apartment, hotel room or other bed room.

If dusts are not an important part of your chemical or heat treatment protocols, you may be missing out on a relatively economical, effective and safe option to improve your success rate against these adaptable and tough-to-kill pests.  


Monday, August 1, 2016

Zika the real deal for Texas PMP

More than 1600 cases of Zika have been reported in the U.S. so far, but until last week all of these had been in travelers--people who caught the virus somewhere else and brought it here.  As of last week, however, the picture is changing.  Last week four cases among people who had not traveled outside of their town were reported from north Miami in south Florida.  In an alarming development for Miamians this morning, 10 new locally acquired cases were reported today, likely signalling the first home grown epidemic of Zika infection in the U.S. All cases so far have been restricted to the north Miami neighborhood of Wynwood.

Jackie Thornton's Zika rash appeared about ten
days after he became infected.  It itched like
measles, he said.
Could this happen in Texas, or other states?  Absolutely.

When Jackie Thornton volunteered at his church to go on  a summer mission trip to the island of Dominica in the eastern Caribbean, the last thing on his mind was Zika virus.  Jackie is the owner of Alvin Pest Control in Alvin, TX, and long-time PMP.  "I was more worried about bed bugs," he admitted.

But when he arrived on Dominica (pronounced doe men NEE kah), someone mentioned that Zika and Chikungunya cases had been reported on the island.

Life in Dominica is a world away from a Texas suburban town like Alvin. Nighttime temperatures this time of year typically hover around 85 degrees F. Not so hot that air conditioning is a necessity, and besides few could afford such luxury.  The home where Jackie and his team slept was typical for the area.  Keeping cool at night depended on a nice breeze coming through one of the unscreened windows.

Knowing that Zika was around, and being an Associate Certified Entomologist, Jackie got interested in what was flying in his window.  Each night he would catch a few mosquitoes that looked more like house mosquitoes than the yellow fever mosquito, believed to be the primary Zika carrier.  Maybe things wouldn't be that bad after all.

But he got worried again about Zika about a week after arriving. "I developed a low grade headache that seemed to be behind my eyes," he said.  "It was worse when I woke up and lessened as the day progressed."  Eventually four others on his team also got sick, but not enough to keep any of them from working their shifts at vacation Bible school and helping repair homes damaged by Hurricane Erica.

After returning to Texas on July 24 the headaches persisted.  Two days later he woke up with joint pain in his hands, elbows, knees and feet, he said.  The next day, about a week and a half after the first headaches started, he went to the doctor for his joint pain.  On the way to the clinic, an itchy rash broke out "head to toe".  It was like having measles, he said.

Red itchy eyes was the only classic symptom of Zika that Jackie didn't have.  But he says he saw plenty of folks with red eyes while he was there.

Today, two and a half weeks after the first headache, he still itches, but the headache and joint pain is not as bad.  In typical PMP trouper fashion Jackie said he never felt like he had to be bedridden, but that it's been an "uncomfortable nuisance".  Indeed Jackie worked at his pest control company all last week, albeit while wearing long sleeves and lots of insect repellent to reduce the chance of starting his own Alvin, TX epidemic (an important community health precaution for any returning traveler, sick or not).

He now says, with a little bit of irony, "I may be the first U.S. PMP to come down with Zika."

I tell Jackie's story to remind us all that the risk from Zika virus is real... especially for anyone traveling to an area where Zika infections are active.

To see a map showing cities at highest risk for Zika this summer, click  http://www.cbsnews.com/news/zika-virus-mosquitoes-us-cities-most-at-risk/

To learn more about "Zika precautions for Women", see http://citybugs.tamu.edu/files/2016/06/Ento-053-Zika-Precautions-for-Women.pdf  and "What Texans Need to Know About Zika" see http://citybugs.tamu.edu/files/2016/06/ENTO-052-What-Texans-Need-to-Know-about-Zika.pdf