Friday, January 31, 2014

Spring IPM Conference in Dallas

It's hard to believe that the Spring IPM conference is just around the corner.  But in just a little over the month we'll be offering our annual
Spring CEU conference at the Dallas Center.  Speakers this year include Ross Eckstein (Mastering fire Ant Control), Laura Miller (Rose rosette disease and its management demystified), Dr. Casey Reynolds (Sprayer Calibration to Maximize Your Weed Control), Janet Hurley (Pesticide regulatory update), and me talking about Neonicotinoid insecticides and the environment: What you need to know. Talks will provide CEUs for both Structural and TDA in General (Pest, L&O, Weed), Laws and Regs, and General (IPM).

Early registration is $70, and it includes a meal.  In addition to the five presentations, there will be an outdoor sprayer demonstration and a short update on a new pest, spotted wing Drosophila, by our new Extension program specialist, Mr. Erfan Vafaie.

So if you want to get an early start for 2014 on your continuing education, this is the best place to come. To register, go to AgriLife registration site.   For a copy of the brochure with more program information and directions, click here.

Thursday, January 23, 2014

Winter Structural Pest Control Advisory Committee

I just returned from the Texas Department of Agriculture's quarterly Structural Pest Control Advisory Committee meeting.  The purpose of the committee is to advise the TDA and its commissioner on education and curricula for PMPs, examinations, proposed rules and standards on technical issues related to pest control, fees and other issues affecting the practice of pest control in Texas.

Today's meeting was relatively brief, but informative. We met two TDA staffers that work actively behind the scenes on pesticide-related issues.  Rafael Paonessa is in charge of reviewing and approving the structural pest control CEU courses that all license holders must attend each year.  Rafael is the person I deal with to get approval for CEU classes that we offer.  He is always efficient and easy to work with.  He reported on recent overhauls of forms and procedures used in the re-certification program.

The biggest changes in the recertification process are in how course providers handle class attendance records, a subject I wrote about in detail last November.   The most common issue in getting courses approved, he said, is when providers do not provide enough detail about the planned course(s).  It's important to provide enough information for his office to determine whether the course meets department guidelines. It's also important that class content relates directly to pesticide use or pest management. General horticultural topics, or workplace safety topics (unrelated to pesticide safety), for example, will not be approved. The department does conduct spot checks of CEU classes to make sure the content is being covered and does not consist of advertising for a particular product or company.  Detailed information on putting together a course for CEUs is available in the just revised Pesticide Recertification Course Accreditation Guide, which is available online.

A new EPA-mandated Pollinator Protection Icon
will appear on many new pesticide labels.
The other employee we met today was Dale Scott. Dale handles the pesticide product evaluation and registration system at TDA. Many people believe that EPA is THE agency that approves pesticide labels, but in fact all pesticides must also be registered by each state in which they will be sold. This is why not all pesticides are registered, or legal for use, in all states.  Approximately 16,000 pesticide labels are registered in the state at any time, and his office processes about 3,500 new pesticide registration requests every year.

Dale reviewed information about new pollinator protection guidelines that are beginning to appear on pesticide labels. Four neonicotinoid insecticides will be the first insecticides to come under the new pollinator protection label guidelines. Changes to look for include pollinator protection information under all Directions for Use statements, a new bee icon to draw attention to pollinator protection information, and consistent warning label language about applying insecticides when bees are actively foraging.  This is a topic that all pest management companies and technicians should be aware of. Dale promised to make his PowerPoint on the topic available to the committee.

Also, Maron Finley, IPM in Schools specialist in the department reported on the top ten violations found in school IPM program inspections this past year. Most, he noted, related to inadequate record keeping. In order, they included:

  1. No written guidelines that identify pest thresholds.  (155 violations, 39% of schools)
  2. Not maintaining records showing approvals of Yellow Category pesticides (93 violations, 23% of schools)
  3. IPM program records not maintained for the required time period (64 violations, 16% of schools)
  4. IPM Coordinator not conducting periodic facility inspections (63 violations, 16% of schools)
  5. No system for keeping records of facility inspection reports, pest control service reports, or pesticide applications (57 violations, 14% of schools)
  6. No plan for educating and informing school district employees about their roles in the IPM program (54 violations, 13% of schools)
  7. No monitoring program to determine when pests are present (48 violations, 12% of schools)
  8. No reference [in the IPM policy] to Texas laws and rules governing pesticide use and IPM in schools (40 violations, 10% of schools)
  9. IPM Coordinator training not completed within six months of appointment (32 violations, 8% of schools)
  10. Name and license numbers of persons applying pesticides not on file (31 schools, 8% of schools)
A more serious violation, which occurred only 10 times, and did not make the Top Ten list, was applications made by non-licensed applicators.  Maron noted that 9 of these violators were small, class 1A to 3A, schools, and that all were in rural communities.  

Several on the committee commented that the overall violation rates seem low, and that compared to when the school IPM program first started, the state has made very good progress.  Nevertheless, everyone agrees that there is more work to be done to increase compliance.  Stephen Pahl expressed the desire for TDA to do more outreach to school administrators.  TASB, TASBO, and TASA are three school-oriented organizations that have ongoing meetings where school IPM talks can be presented.  George Scherer, of Texas Association of School Boards, was present and commented during public testimony that it is possible to get the names and contact information for school board members if needed during the compliance assistance phase of helping a school district.

Arnold Anderson, from Katy ISD, provided testimony on the subject of violations during the public comment portion of the meeting.  He suggested that schools with little experience in IPM should be encouraged to seek out a mentor school district rather than being fined. A suggestion was made that perhaps the TDA could facilitate mentoring by maintaining a current list of districts willing to mentor other districts in their IPM program development.  This might be another way TDA could reduce the number of school IPM violations without having to resort to administrative fines or penalties.

Finally, we were advised today that there is still an opening on the Advisory Committee.  If you know of someone who is not connected directly or indirectly with the pest control industry, and is interested in serving as a public member of the committee (with no pay or travel reimbursement), Leslie Smith is accepting applicants.

Tuesday, January 21, 2014

Careful use of Nuvan strips

It may never be as big a seller as Vogue,
but the CDC's Morbidity and Mortality Report
covers some interesting news for PMPs.
The Morbidity and Mortality Weekly Report from the Centers for Disease Control will never make's Best Sellers in Magazines List.  In fact among all the subscriptions I receive, I'd be hard-pressed to think of one with a less appealing title. But sometimes this report has very useful information for entomologists and pest management specialists. This week's Notes from the Field feature looks at statistics concerning acute illnesses associated with Pest strips containing the insecticide dichlorvos (DDVP).

For anyone unfamiliar, dichlorvos is the active ingredient in (among other products) Nuvan™ Prostrips™, a slow release pesticide formulation for control of bed bugs, "flies, gnats, mosquitoes, moths, silverfish, cockroaches, spiders, beetles, earwigs and other pests".  Dichlorvos looked like it might have seen the last of its days a few years back, at least partly because of its acute toxicity. It is a holdover from the era of organophosphate insecticides, and like all OPs, it acts as an acetylcholinesterase inhibitor.  But dichlorvos has a unique property: its relatively high volatility makes it useful as a fumigant.  And thanks to its effectiveness against bed bugs, dichlorvos now appears to be staging a comeback.

Dichlorvos kills pyrethroid-resistant bed bugs. But it can also hurt people if not used carefully as described in the label. The CDC study reports on 31 acute DDVP pest strip–related illness cases recorded from seven U.S. states and Canada from 2000 to 2013 (more cases undoubtedly occurred that were not part of this study). Most of the illnesses resulted from using the product in commonly occupied living areas (e.g., kitchens and bedrooms), in violation of label directions. According to the report, "Although 26 of the 31 cases involved mild health effects of short duration, five persons had moderate health effects."  Illnesses included neurological, respiratory and gastrointestinal symptoms. Effects due to dichlorvos overexposure usually resolve themselves completely, according to the study; but make no mistake--this insecticide should be used with care.

The report concludes that in order to prevent dichlorvos-related illnesses, the public should be educated on correct use of pest strips, and how to control insect pests using safer pest control methods.  I would add that it's important for professionals to be reminded of the safe use of these products and the importance of reading the fine print on dichlorvos labels.

Some key label points to remember about Nuvan and similar strips:

  • Do not over-apply.  One 16 gm strip is sufficient for treating 100 to 200 cubic feet.  Having said that, do your technicians know how to estimate cubic feet?  A typical 6' by 12' by 8' walk-in closet is approximately 575 cubic feet (a simple multiplication of length x width x height) and would require 3 to 5 strips--6 would be an over-application.
  • Around the home, strips may only be used in closets, wardrobes and cupboards, storage units, garages, attics or crawl spaces. Other sites outside the house are also listed on the label.
  • Do not use in kitchens or food prep or storage areas where unwrapped food may be exposed.  Kitchen utensils should not contact the strips.
  • Pets and children should not play or sleep where strips are in use, nor should the strips be used in any room where humans are likely to spend more than four hours a day. An important sidenote here: most of the illnesses (65%) reported in the CDC paper occurred when exposures exceeded four hours per day.
If you or your technician encounters a customer using dichlorvos strips, you owe it them to make sure they understand the risk of the product and use it only after carefully reading and following the label.

And if you'd like to receive the Morbidity and Mortality Report for it's occasional pesticide and pest-related stories, you can subscribe here

Thursday, January 16, 2014

A lousy problem

Head lice are well adapted to living in human hair, but are
almost never found living off of the head.
One of the most fascinating sibling rivalries in entomology has to be that of the human louse, Pediculus humanus.

The version of this species of louse that most of us are likely to encounter is the head louse Pediculus humanus capitus (the reason for the extra Latin name in the scientific name is that the head louse is a subspecies of the human louse).  The head louse, as most elementary school teachers know, lives exclusively on the human head--and seems to especially relish grade-school children.

The other subspecies of the human louse is the body louse, Pediculus humanus humanus. The body louse is mostly physically identical to the head louse, but has a distinct feeding preference for the body rather than the head.  Body lice do not venture to the heads of their human hosts; but leave the head region to their slightly leaner, head-inhabiting cousins.  It is thought that the two subspecies parted ways some 100K years ago, when humans began to don clothing on a regular basis.  Today, the body louse thrives only on people who change their clothing infrequently.  This because body lice rely on clothing as a hiding place between blood meals, and frequent changing of clothes and showering tend to eliminate infestations.  In the U.S. today, the main group of persons who maintain body lice infestations are in homeless communities of large cities.  The two lice subspecies do not interbreed in the wild, although when forced, they will breed in the laboratory under the prying eyes of entomologists.

The body louse, while less familiar to affluent Americans today, has played a huge role in human history. Body lice transmit  human typhus, one of the major deadly human diseases.  When Napoleon's half million man army attacked and was defeated by Russia in 1812, it's said that more French soldiers died from typhus than were killed by Russians.  In 18th century England, "gaol fever" (another name for typhus) killed more prisoners than all the public executioners in the British realm.

Lucky for us that the head louse does not seem to transmit typhus or any other human disease. It's no wonder, then, that entomologists and physicians have long wondered why the difference between the two lice.

Newly published research by University of Illinois entomologists, summarized in the ESA's Entomology Today may provide some insight into this question.  DNA analysis suggests that it all comes down to seemingly minor differences in the immune responses between the subspecies.  According to one of the authors, Barry Pittendrigh, head lice have a stronger immune response than body lice.

“Our experiments suggest that the head louse immune system is fairly effective in fighting off the bacteria that cause trench fever" (another louse-transmitted disease), Pittendrigh said. “However, the body lice don’t seem to have as good an immune response.”

While reasons for the body louse's weaker immune response is speculative at this time, part of the explanation may have something to do with bacterial ecology inside the bug. Many bacteria live inside insects, some good and some bad for the host.  Body lice appear to get extra vitamins from their bacteria, consequently they tend to be a little larger than head lice, according to the story. So for body lice, a weaker immune system may be beneficial.  Unfortunately, the weaker immune system also allows bacteria that cause typhus and trench fever and the like to survive.  Why head lice seem to follow a different survival strategy is still a puzzle.

I'll admit that all of this is pretty far removed from the very practical vocation of pest control, but ultimately these sorts of biological questions have implications for why pests are pests--and sometimes how they can be controlled. Bed bugs, for example, harbor a bacterium called Wolbachia, which a lot of researchers are interested in at the moment. Some think that the Wolbachia bacteria may help explain temperature sensitivities of bed bugs, and might hold a key to new control strategies. Similarly, studies of termite gut micro-flora may someday point to better baits or wood protectants.

So the next time you encounter a head louse, wonder a little bit at the long path it's taken to become one of the most successful human parasites.  And be thankful it has a strong immune system.

Thursday, January 2, 2014

Rubbing alcohol not a good option for bed bug control, says researcher

Improper application of an insecticide dust to a
mattress and pillows by a non-professional. Dusts are
designed for light application to crevices and
voids, out of reach of  people.
The quest for home remedies for bed bugs appears to be never-ending. However, according to the latest reports, it seems that very few over-the-counter insecticides, or home remedies, are worth the time or trouble when battling bed bugs.

A recent article in Science News gloomily summarized some of the most current information about DIY bed bug control, based on papers presented last month at the annual conference of the Entomological Society of America in Austin, TX.

It will come of little surprise to most PMPs that rubbing alcohol, bug bombs and other products just don't work that well. And some products, like ultrasonic repellers, are completely ineffective. Science News reported that rubbing alcohol killed only about half of the bed bugs that were sprayed directly, in work conducted by Changlu Wang, of Rutger's University. Bed bugs confined in a plastic bag for seven days with mothballs (a much higher exposure than you would expect in a clothes closet or storage chest) had about the same survival rate.

I recently had the opportunity to attend the Global Bed Bug Summit in Denver, CO.  One of the debates at that meeting was over the effectiveness of diatomaceous earth (both a professional and DIY product). Despite the fact that PMPs have reported success with d.e. over the years as part of an IPM program for bed bugs, some researchers question its effectiveness in the field.

Despite the fact that no resistance to d.e. among bed bugs has ever been documented, it is never been hailed as a miracle product. Appropriate application sites for d.e. are limited. It is not really designed for broadcast use, and few applicators, especially non-professionals, know how to apply dusts correctly (see image). To liven the debate, one recent field study  by Michael Potter's lab in Kentucky found that professional applications of d.e. provided inconsistent, or only marginal, bed bug control when used by itself, without sprays or other supplemental treatments. Field studies like these are much more difficult to conduct, but usually provide a better estimate of how a product is likely to perform in real life, compared to laboratory tests in a Petri dish (Potter, by the way, contends that silica aerogel, found in professional products Drione® and TriDie®, is a more effective desiccant than diatomaceous earth).

Why the conflicting results? No one knows for sure. But d.e. is an abrasive that scrapes away some of the protective waxes that keep bed bugs from drying out (desiccating) in the dry indoor environments of homes. The effectiveness or ineffectiveness of d.e. may have something to do with the source or form of the diatomaceous earth (the various d.e. products are mined from different geological deposits and thus may vary in abrasiveness), or it may have to do with the ambient humidity or availability of food. Many insects compensate for water leakage cause by desiccant dusts by taking in more water from feeding. Perhaps bed bugs in the field are able to compensate for moisture loss by taking in more moisture through more blood feeding. Not a pleasant thought if you're the one being fed on.

All of this, of course, supports the idea that professional pest control is the best option for bed bug eradication. As a professional, your training and expertise can provide a lifeline for the public in desperate search of a bed bug solution. The professional products at your disposal are superior to most over the counter products, and your ability to problem-solve gives you a big edge over weekend bug-killing warriors.

There will always be do-it-yourselfers. But there is also a great need for trained professionals to get the job done safely and effectively. Let's get out there and show them how it's done.

Is your customer left holding the bag?

Bagged items following an insecticide treatment for bed bugs. 
One of the great conundrums of bed bug service is what to do with the mounds of clothing, shoes, electronics, books, papers and other personal items that must be bagged prior to, or during, a bed bug treatment. These items are potentially infested with adults, nymphs and bed bug eggs, and should not be returned to the home until all bed bugs inside are killed. So what to tell the customer?

Clothes are usually the least troublesome bagged item, because they can be run through the washer or drier.  But many bagged personal items are not appropriate for the laundromat.  What can be done for non-washable items that might harbor bed bugs?


There are several options for treating "hard items" like books and electronics.  Heat is one of the best choices, because bed bugs don't do well in heat. A study by Stephen Kells and Michael Goblirsch from the University of Minnesota, showed that bed bugs exposed to rising temperatures for two hours began to die at around 104 degrees F, though eggs were not greatly affected by this temperature.  Both adults and eggs were  killed immediately by exposure to 122 to 131 degrees F, respectively.  The authors concluded that bed bugs in a room could be eliminated by heating all parts of a room to 122 degrees F for an hour, a guideline followed by most heat treatment companies today.

These same heat treatment guidelines can be used for heat-treating hard or soft goods in garbage bags.  The cheapest and easiest way to accomplish this is through solar heat during the summer months.  People have used this method for many years, especially in tropical areas where mattresses and clothing can conveniently be bagged and placed in the sun all day to kill bed bugs.  My summer intern and I attempted to replicate this approach in 2012 by bagging 7 lbs of soft goods in both clear and black plastic bags on a summer afternoon with an ambient outdoor temperature of 95 degrees F.  We put the bags on pavement at mid-morning and monitored temperatures within the bags through the afternoon. Thermometer readings in the clear plastic bags easily exceeded the lethal temperature for the minimum one-hour exposure; however black plastic bag contents never exceeded the one-hour lethal temperature required to kill all adults and eggs.  We found that even when daytime air temperatures stayed under 90 degrees, clear bags can heat soft goods sufficiently to kill bed bugs.

Many people are surprised that, when it comes to heating, clear plastic bags are superior to black. We've all been taught that black absorbs heat; however in this case the greenhouse heat-trapping effect is more powerful than bag color. The greenhouse effect happens when the short visible and UV wavelengths pass through the clear bag and begin heating the objects inside. The same plastic keeps the radiant heat produced by light inside the bag. Black plastic doesn't let much visible light through, so greenhouse heating effect is minimal. Hence clear is hotter than black (and tinted windows do keep a car cooler in the summer, as Texans will tell you). A second important advantage of using clear bags in bed bug work is that the customer can see what items are stored in the bags, for easier retrieval.
Temperatures from the middle of clear and opaque black plastic bags set
outdoors on a clear summer day with a maximum ambient temperature of
95 degrees F. Note that only temperatures in the clear bag exceed the lethal
temperature for bed bug adults and eggs. M. Merchant, unpublished data.

Clearly, solarization provides one simple, fast and inexpensive solution for dis-infesting personal belongings during the summer.  To make sure that lethal temperatures are reached, I suggest using a relatively inexpensive wireless (or wired) weather monitor with thermometer capabilities, in the middle of whatever items are in need of treating.


But what if it's not summer, or you live in areas where outdoor temperatures just aren't that hot? Another option is cold.  Unfortunately, cold is not a very fast or effective treatment for bed bugs.  Simply putting items in the refrigerator freezer is not a guarantee of lethality.  Dr. Dini Miller, at the recent bed bug summit in Denver, CO, reported that five bed bugs (out of 200 bed bugs) in a vial she stored in a refrigerator freezer for TWO YEARS recovered on removal from the cold. Granted, colder temperatures do kill bed bugs eventually, but cold is not a reliable or fast method to disinfest bags.


The final option for killing hidden bed bugs is use of fumigants.  Fumigants are insecticides in gas form, and hence have the potential for penetrating many substances to kill hidden pests. Nuvan™ Prostrips placed in plastic bags is a fumigant option used by many PMPs.  These strips were tested as a means of controlling bed bugs in infested items by Dini Miller's Virginia Tech lab.  While dichlorvos, the active ingredient in Nuvan™ Prostrips, is toxic to bed bugs, it's ability to provide 100% control was limited in the Virginia tests.  The only time Dr. Miller's group was able to document 100% bed bug adult and nymph mortality was with hard goods when bags were held for 14 days (significantly longer than the 48 hour "minimum" time recommended on the label). Miller's lab concluded that dichlorvos is a slow dispersing fumigant and that the limited air flow in closed bags makes it difficult for dichlorvos to reach bed bugs in small crevices of enclosed items. Soft goods were much more difficult to treat with fumigants because of more limited air flow through clothing and fabrics.

Another bed bug fumigant tested by Miller's lab, and now being actively marketed for use in bags, is Cirkil®.  The Cirkil® active ingredient is neem oil, a plant-based extract with a good safety record and the cachet of being a natural product.  Terramera, Cirkil's manufacturer, has just published a new protocol for using the product that they refer to as "Rag in a Bag". The method involves spraying the undiluted product on a rag and placing it with the items to be treated in plastic bags. The protocol is based on Miller's research that showed that one treated rag could effectively fumigate a bag with hard goods in 3 days.  One big drawback of the Cirkil product, according to some who have used it, is the strong, lingering odor of the product.  If you are interested in this product, I suggest you try it on a small scale to assess the odor issue before subjecting clients to a potentially smelly product.

Lastly, carbon dioxide has been suggested as a means of controlling bed bugs in plastic bags. Dr. Changlu Wang from Rutger's University has tested placing commercially available dry ice pellets in plastic bags to kill bed bugs. As I reported in an earlier blog, Wang found that 3 lbs of dry ice in a 42 gallon (3 mil-thick) garbage/yard waste plastic bag was sufficient to suffocate all stages of bed bugs in up to 22 lbs of clothes, when held for 24 hours. This amounts to a cost of approximately $4 to disinfest 22 lbs of clothes or other items that would fit in the bag.  Sounds like a great option, except that the U.S. EPA considers carbon dioxide to be an insecticide and discourages its use for safety reasons. Indeed, CO2 can be toxic in high enough doses, and several leaking bags in a bed room (all bags will leak) or other closed living space could certainly elevate gas levels into the range of health concern to humans. Until the EPA gets this figured out, I am reluctant to recommend use of dry ice as a bag treatment.


So where does that leave the average bed bug client?  As we've seen, heat, cold and fumigants all have their place, but their usefulness can be limited.  If none of these options works, the client may be left holding the bag--literally.

But even when the only option appears to be waiting, the wait isn't forever. Bed bugs without access to blood will eventually starve. But how long does it take to kill bed bugs?  Current research on bed bug longevity suggests that 3-5 months is long enough to starve bed bugs.  This is a long time, but not an impossible task, especially for personal items that are not immediately needed. For this reason, it may be a good idea to suggest to your clients that they store items together that do not need to be used quickly. It may be possible to use some of the methods listed above on higher priority bags and let the rest just sit. And items that are needed immediately can be individually inspected and/or washed if you are unsure whether there might still be live bed bugs hidden within.  This option is probably good for children's toys that cannot be placed in the wash.

When storing bags, keep in mind that the warmer the temperature, the shorter the lifespan of starving bed bugs. A warm bed bug respires faster, consequently using up its energy stores more quickly. If you keep bagged items at 70 degrees or higher it should be safe to remove items after three months.  But if they've been stored at slightly cooler temperatures, you may want to keep those bags shut a little longer. Putting bags in an unheated shed or closet outdoors might not be the best solution if those bags are needed within 5-6 months. Remember the bed bugs that survived the freezer for two years?

If your company conducts bed bug control with insecticides, the question of what to do with bagged items is critical. Because each client and job is unique, it's up to you as a professional to advise your customer what their best options are for handling those important personal items.  After all, no one wants to be left holding the bag--especially one full of bed bugs.