Bermudagrass stunt mite in lawns

The tufted witches broom symptoms of BSM in
are seen in the stem on the left.  Normal
bermudagrass stem on the right. Photo: M. Merchant.

I don't often address pest issues in lawns and on ornamental plants; but many Insects in the City readers do include lawn care services. So I thought I would address a lesser known turfgrass pest problem that seems to be on the increase.

Bermudagrass stunt mite (BSM), Eriophes cynodoniensis, is one of our tiniest arthropod pests of ornamental plants.  It lives inside the leaf sheaths of grass and is a common (but relatively minor and spotty) pest of home lawns. On golf course greens, where expectations of smooth putting surfaces are high, BSM is a serious pest throughout the southern U.S. According to some experts, the incidence of this pest appears to be on the rise--possibly because of the loss of older insecticides, a trend toward higher mowing heights and less irrigation, and possibly the use of newer, more susceptible grass varieties.

The BSM feeds only on bermudagrass (though there are closely related species that feeds on buffalograss and zoysiagrass). When the mite feeds under the leaf sheaths the leaves start to yellow and twist. As the grass tries to grow, the gaps between the leaves get shorter and shorter, resulting in a bunchy, "witches broom" appearance. Eventually the leaves and stems die, probably as a result of a toxin injected into the grass by the mite.  Look for areas of stunted, green to brown grass, and dead spots in a lawn. You can identify BSM damage by the stunted, tufted appearance of the grass around the edges of the dead spots.

Damage often seems to occur in grass that is stressed from not receiving enough water.  In my own yard for several years I commonly saw BSM damage in the median strip between sidewalk and street. Since upgrading my sprinkler system, however, I see fewer signs of these mites.

Dr. J.C. Chong, of Clemson University, got interested in this mite about 10 years ago, and found no one else studying it.  Today he has devoted as much time as anyone to studying these tiny pests.  His knowledge about BSM is in especially high demand this year, he says.

"I am getting more requests for diagnosis and confirmation from golf courses and high-end landscapes in Florida, the Carolinas and Texas in the past 3 months than the entire [2016] combined."

Damage from BSM appears as brown, dead patches.  Examine the borders of
these spots closely to look for the tufted, stunted plants typical of the mite.

According to Chong, the last time anyone bothered to studying control of BSM was in the early 1980s. At the time, the best insecticide by far was diazinon. Now that diazinon is no longer available due to environmental concerns, we have few comparable products.

Part of the problem is that there are few researchers with time or funding to study BSM.  Another problem common to turfgrass pests is that it is difficult to know if and where mites will show up in a large enough area to design a good insecticide trial.

Bifenthrin is a standard go-to miticide for many in the pest control industry. But experts vary in their opinions about its effectiveness against BSM.  Bifenthrin, lambda-cyhalothrin, and deltamethrin products all carry labels for mite control in turfgrass, and may provide some control.  However, if you are attempting control with one of the pyrethroid insecticides experts advise using a surfactant to help the insecticide penetrate deeper into the leaf sheath. Dr. Eric Rebek, at Oklahoma State University, suggests using Dispatch at 3/4 oz. per 1000 ft sq. Rebek also noted that Dursban provides slightly better control of BSM than the pyrethroid products, but can only be used on sod farms, in road medians, around industrial plants or on golf courses (brand products differ, so check the label).

Chong has had little success with bifenthrin, regardless of timing.  In trials conducted between 2011 and 2015, he found avermectin to be the best treatment after diazinon. He used Avid 0.15 EC at 28 fl oz/acre, at two week intervals. When testing weekly applications, Chong found the best mite suppression came from four weekly applications in June compared to four weekly applications in April.

Another suggestion passed on by many experts is to scalp, or mow the grass to be treated very short, before applying insecticide. The reasoning is that this prunes off and removes many of the infested grass tufts, plus opens the grass canopy to better spray coverage. Bagging your clippings and disposing of them off site will ensure that the mites are not just spread around by the mowing operation.

On golf courses Chong now recommends Divanem (8% abamectin, by Syngenta).  A Restricted Use nematicide, Divanem has a 2ee registration for bermudagrass mite control on greens, tees and fairways (March 2017). Rate is 3.125 to 6.25 fl oz/acre.  He recommends using the high rate if economically possible, and repeating every 2-4 weeks.

Despite several years of field tests, Chong notes that there is still a lot to learn, especially when it comes to combining insecticides with different cultural practices like mowing, irrigation and varietal selection. Experience with BSM demonstrates that, at least for some pests, it's not always easy to come up with reliable management recommendations.  For a pest like BSM, one pest can lead to a career's worth of work for some lucky entomologist.

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.  

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!

New resource for managing turfgrass pests

If your business has anything to do with keeping turf and lawn areas beautiful and healthy, you're going to want this new book just published by Texas A&M AgriLife Extension.   (120 pp., 52 tables) The Weed, Insect, and Disease Control in Turfgrass guide was written by Extension specialists Casey Reynolds, Matt Elmore, Young-Ki Jo, and Diane Silcox Reynolds. It's probably the best single reference to pesticides used in turf, at least in Texas.

Despite some who claim that we need to eliminate turf to save water and reduce pollution from fertilizers and pesticides; healthy turf is essential for our urban areas.  Turfgrass is vital to our parks and urban landscapes, athletic fields, and golf courses; it helps moderate temperatures in urban areas, it holds the soil, and provides a soft cushion for our lives. Unfortunately, southern turf is often challenged by numerous weeds, insect pests and disease.  But with proper selection and judicious use, pesticides can help turf do these jobs better with minimal impact on the environment.

Information in the Weed, Insect, and Disease Control in Turfgrass 2016 guide will help you select the herbicides, insecticides, and fungicides you need. But the guide is far more than a listing of  pesticides.  It includes information on pesticide modes of action, turfgrass tolerance, application rates. It also provides an annotated, pest by pest index of labeled pesticides.

Hard copies of this book are available through the AgriLife Bookstore for $20.  But the electronic version is available for free download here. Also, if you haven't seen the new and updated Aggie Turfgrass website, check it out.  It has excellent descriptions of the most important Texas turfgrasses, and management information for weeds and insects.  It also has links to past and upcoming events like turfgrass field days in Dallas or College Station.

Pesticides and ADHD

In case you haven't seen or heard the story this week about scientific research showing a link between pesticides and attention-deficit/hyperactivity disorder (ADHD) in children, I think it's important enough to pass on.  According to the Time magazine story, researchers at the University of Montreal and Harvard University this week reported in the journal Pediatrics a statistical correlation between ADHD and exposure to organophosphate (OP) pesticides.

Before discussing the results, we should note that there are different ways to study environmental causes of disease.  The most straightforward approach is to take a randomly selected group of subjects from a population you are interested in (say males of a certain age), and subject them to a level of the environmental chemical or condition, say pesticides, or microwaves from cell phones, etc.  You then compare the health of this exposure group over time to a randomly selected group of subjects without the exposure.  This type of controlled experiment is one of the more rigorous ways to test an hypothesis and show a cause-effect relationship.  However, this sort of approach is rarely possible for practical and ethical reasons.  Who wants to volunteer themselves for a study of the possible effects of a toxic chemical on your health?  Fifty dollar stipend anyone?

Another approach would be to look for people who have been naturally exposed (via their lifestyle, or home environment, etc.) to an environmental chemical and compare their health parameters to a group who has not been naturally exposed.  This is a valid research method and has been used many times to study the effects of environmental chemicals on human health.  It's important to realize, however, that this approach measures correlation, which is not the same thing as cause and effect.  If they looked, for example, researchers might find a correlation between heart attacks and watching at least two football games on TV each week.  This would not, however, prove that watching football causes heart attacks.  The actual cause could be something entirely different.  Something co-related to football watching, like lack of exercise and big bowls of greasy nachos!!?  The point is that it is very easy to have a correlation without a cause and effect relationship.

Of course this was the same argument cigarette companies made for many years.  Correlations, if done properly, can provide valuable suggestive evidence, but must always be looked at critically to make sure that all relevant variables have been properly controlled. Typically correlative studies are done as preliminary to a more rigorous study, or as a second choice when more rigorous studies are not possible to conduct.  We cannot afford to dismiss correlations as uninformative.

In the case of this study from the University of Montreal, Maryse Bouchard and a team of colleagues analyzed the levels of chemicals called dialkyl phosphates in the urine of more than 1,100 children ages 8 to 15.  Dialkyl phosphates (DAPs) are metabolic "breakdown" products of OPs. Like nacho crumbs left in the sofa cushion, DAPs are left behind in the blood and the urine after someone has been exposed to OP pesticides. Measuring DAPs in blood and urine is much more sensitive than acetylcholinesterase tests (used by many PMPs in the past to measure OP overexposure), and an accepted way to document previous exposure to OP pesticides in epidemiological studies.  Bouchard's study found that children in the study group with the highest levels of which are breakdown products of OPs had the highest incidence of ADHD.  In other words, there was a correlation between DAPs and ADHD.  To see a free abstract of the study, click here.

The researchers, as all good researchers should, made it clear that this is a correlation which falls short of proof that organophosphate insecticides are a cause, or even a contributing factor to, ADHD.  I am no expert on ADHD, nor on the validity of the chemical analyses or the epidemiological methods used by the authors of this study, but studies like this serve as a cautionary tale for the use of pesticides in urban environments or on food.  The possibility of subtle health effects on humans is always present with the widespread use of synthetic chemicals. But the potential risks always must be weighed against the undoubted benefits of pest control.

Here are a few things to keep in mind should you find yourself in the position of justifying to local media or your customers the use of pesticides as pest control tools.

• The pesticide class which was the focus of this study is, for the most part, no longer widely used in the pest control industry.  Organophosphates (such as diazinon, malathion, chlorpyrifos, acephate, and safrotin) have been largely supplanted by pyrethroid insecticides and even newer classes of chemistry.  The results of this study apply only to OPs and not to all pesticides.
• The study did not attempt to prove a cause-effect relationship between OP pesticides and ADHD.  The study, for example, as the authors admit, could not fully rule out that some behavior factor common to ADHD children might cause them to have higher frequency of contact with OP pesticides. 
• The source(s) of OP exposure was not identified by the study.  Much of the exposures of children to these older pesticides likely come from dietary sources, especially since OP use by the pest control industry was already in decline during the years when the data was collected. 
• Any pest control company practicing IPM and safe application methods should at best be a minor and occasional source of pesticide exposure to customers.  Risk, or toxicity, of a pesticides is a product of two factors: (1) the toxicity of the pesticide and (2) how much exposure one has to that pesticide.  If labels are being followed, care is being taken to place pesticides only in places where people are unlikely to contact them, and lowest risk pesticides are being used, then the risk of harm to human health should be very small.

The results of this study do not negate the regulatory process that evaluates the safety of pesticides in use by the industry today.  Testing required by the U.S. Environmental Protection Agency for pesticides remains some of the most stringent consumer product testing in the world.  That said, no regulatory system can guarantee safety of any product or practice.  It's often said you can't prove absolute safety, because that's the same thing as trying to prove a negative--it's beyond the scope of experimental science.  We can only hope to guarantee a certain level of safety.  That is why a 100-fold safety factor is built into our current pesticide regulatory system, and why continual review of pesticides goes on between agency and manufacturers.  If a causal relationship is determined to exist between OP insecticides and ADHD, this new data will be taken into account by the EPA, and regulatory changes will undoubtedly be made, as they have for other pesticides.

If I were convinced that we could do IPM effectively without pesticides, I would certainly be a supporter of "no more pesticides".  But not all pesticides are equally risky, and the reality is that pesticides can be useful and even essential tools in our competition with pests. 

Until we find even safer ways to control pests, I will continue to study the use of pesticides, teach and preach pesticide safety, and recommend their use.  And in the meantime, if you really want to protect your health... cut back on the nachos. : )

Some bed bug do's and don'ts

Dr. Dini Miller, of Virginia Tech University, is one of the principal researchers on bed bugs in the U.S. Yesterday I had the chance to visit with her about some of the latest in bed bug control, and thought I would pass along some of her current advice.

The art of bed bug control continues to evolve, even as bed bugs continue to adapt to the pesticides being used against them. For this reason, one of the essential steps in any bed bug service is to make the home environment less hospitable to the insects. "Clutter removal," Miller says, "is essential." Unnecessary household items should be bagged and, if possible, removed from the home. Clothing should be tightly bagged and restored to drawers and closets out only after the home or apartment has been treated and clothing washed (the heat from driers is sufficient to kill all life stages of bed bugs).

Mattress encasements are a good first line of defense for bed bugs. "Unfortunately, bed bugs can escape from most mattress covers," said Miller. She recommends Protect A Bed bed bug encasements as one brand that is truly bed bug-proof. "One common mistake is covering the mattress, but not the box spring," she said. Box springs, especially the undersides, are excellent hiding places for bed bugs.

Insecticides for bed bugs are one of Miller's special areas of research. According to Miller more and more populations of bed bugs are appearing with resistance to the commonly used pyrethroid insecticides. She offered the following tips when dealing with tough bed bug problems:

• For mattresses and box springs, a good low-toxicity option is Steri-Fab^® insecticide. Steri-Fab^® is a combination of isopropyl alcohol and a short-lived pyrethroid insecticide called phenothrin. It kills all life stages of the bed bug only if sprayed directly on the insects and their eggs, so good coverage is essential.
• For general residual treatments you will get better control when using a microencapsulated pyrethroid. Insecticides made with this formulation tend to stick to the insect and therefore prolong the time that bed bugs are exposed, increasing kill.
• Dusts should be used in void areas and inaccessible sites. Because of its low toxicity, diatomaceous earth can even be used on bedding and furniture. Pyrethroid dusts should be applied only to those areas where people will not come in contact with residues. Dusts carry the same advantage as microencapsulated formulations--they stick well to the insect, increasing time of exposure.
• The aerosol formulation of Gentrol^® provides superior kill over liquid formulations. Miller believes this is due to the higher concentration of the aerosol (0.36%) compared to sprays mixed from concentrate (0.07%).

Miller also noted that at a recent EPA conference she attended on bed bugs a hot item of discussion was whether states should consider adding a special certification category for bed bugs. The idea is similar to the requirement that PMPs must carry a termite certification category on their licenses if they wish to do termite control in Texas. There is a general perception around the country that too many pest control companies are providing bed bug control with too little training or understanding of essential principles of bed bug control.

The fact that this is being discussed seriously should serve as a wake-up call for the pest control industry and for education providers (like me). The message is that bed bug training should be a priority if our industry wants to maintain a reputation for dependable service among consumers. To paraphrase H.G. Wells, when it comes to pest control, as in all nature, it's "adapt or perish".

Demands for mosquito control likely to rise

It seems Hurricane Dolly brought with her more than rain. Following the record rains and flooding mosquitoes have also arrived by the semi-truck load.

Mosquito pressure is often measures in terms of numbers of landing rate per minute. A volunteer will expose a leg and another person will count the number of mosquitoes that alight on the exposed skin for one minute. A recent Harlingen survey put the average per minute landing rate at 120, with a high in one location of 384 mosquitoes per minute! That's a lot of mosquitoes.

A regional spraying effort started this week in south Texas. Airplanes will be applying the insecticide Dibrom to most parts of the lower Rio Grande valley to suppress numbers of especially floodwater mosquitoes that are the first species to come out after a flooding event. For more information about the spray program, see the August 2 article in the Rio Grande Guardian.

The ironic thing about these efforts is that floodwater mosquitoes pose a relatively low threat for arthropod-carried viruses, such as encephalitis and West Nile virus. The mosquitoes that carry these disease pathogens typically come out once waters begin to subside and leave numerous pools of stagnant, standing water. Not to say that spray efforts will not be without effect. Population numbers of the levels described for Harlingen would leave anyone miserable and crying for relief.

Once the huge numbers subside, and the spray planes return to their bases, the pest control industry will have an important role to play in helping reduce the risk of bites and disease. Experienced PMPs can point out to people areas where disease-carrying mosquitoes breed in their own backyards. In addition, the use of residual insecticides applied carefully to mosquito resting places in backyards and surrounding trees can significantly lower mosquito biting rates.

In one study conducted in Kentucky, and reported in the May, 2005 and October, 2006 issues of PCT magazine, backpack mistblower sprayers provided up to 6 weeks suppression of mosquitoes in backyards. Such treatments provide a valuable service to residential customers and can even reduce the risk of mosquito-borne disease by reducing populations of Culex mosquitoes, the primary vector of WNV and the various encephalitis diseases.

With today's landing of tropical storm Edouard, mosquito control will be an important issue for the pest control industry in Texas for the next two months. If you own a business in one of the areas affected by storms this summer, you owe it to yourself and your customers to read the research updates in PCT magazine, linked above.