QUESTION:

I have a customer who wants to know if she has dust mites. How does one verify whether there are dust mites present or not?

ANSWER:

Unlike paper mites, dust mites actually do exist, and often could be present in a home in extremely large numbers. However, there have been a lot of internet sites in the past few years that attempt to sell products to homeowners for dust mite control, and I have a strong suspicion that the statistics these sites throw out there are wildly exaggerated (such as half the weight of your pillow or mattress could be dust mites and their body parts). Many of the items they are selling also are likely to be a lot less effective than advertised, so buyer beware with dust mites.

These are microscopic mites, and verification of their presence would need to be done with a decent microscope or good dissecting scope - something that would magnify probably 80X or higher, allowing you to see with clarity that it is a mite and to see some distinguishing features of it. If present the mites could literally be anywhere in a home, and as common as they are they likely are present in nearly all homes at some level of a population. They rely heavily on high humidity, so regions that are very low in humidity, such as my region in the Central Valley of California, are going to have very, very few dust mite problems. Controlling humidity inside a home is one step in a program for reducing the levels of these mites.

They feed on the tiny flakes of dry skin that slough off of our bodies on a constant basis. This is called dander, and supposedly dander composes a high percentage of the household "dust" that we see building up under furniture or on tops of things. I have read that in the proper light you can see dust floating in the air, and that even this could be dander. So, dust mites have a continual and adequate supply of food. They do not bite or parasitize us in any way, but they are well known as a major cause of allergies in humans. Their fecal material contains a protein that can really set off sensitive people, causing anything from itchy eyes to serious attacks of asthma and difficulty in breathing. It is estimated that up to 1/3 of people have legitimate allergies to dust mites.

You would need to gather some of the dust that you find around in a home and examine it under high magnification to verify the presence of the mites, and if they are present you should have no trouble finding some in your sample. You might place some insect glue traps throughout the home and inspect the glue under that magnification after about a week, looking especially around the edges of the glue where the wandering mites may have gotten stuck. These tiny mites easily become airborne too, and are carried with slight breezes in the home, so they could be on any part of the glue. They are short legged, as opposed to the long legged rat and bird mites, and their body is fairly hairless, compared with cheese and mold mites. They are a creamy bluish color, and on a shiny dark surface you could even see them moving around as light specks.

Control will never eliminate dust mites - there are just too many to get rid of them all. But, unless someone is really suffering from allergic reactions there is no major need to eradicate them. Humidity control, dust removal with a vacuum equipped with a HEPA filter, damp wiping surfaces to remove dust, and the use of a dehumidifier with a HEPA filter can all work together to reduce the mites and the conditions they need. Since beds can often have large numbers of the mites, due to plenty of dry skin and warmth and humidity from sleeping persons, frequently laundering sheets and pillow cases can reduce the mites and the dander they look for. Pesticides would be of very little use in dust mite control.

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QUESTION:

Just a quick question on keeping your tanks, hoses, and pumps clean from product buildup and not smelling. How often should you do a clean out of the system, and what clean out agent do you recommend? Also, how do you dispose of the clean out agent after uses? I have also heard you can use liquid dish soap as a cleaning agent as well. Is this true?

ANSWER:

There are, as you indicate, several good reasons for cleaning out your equipment on a regular basis. One of these is simply appearance and image. Filthy equipment is going to be visible to customers, and their perception of the company that does not keep a tidy truck with clean equipment likely will be much lower than that for technicians who obviously take pride in their property. That filthy hand tank could also transfer unwanted stains onto floors in a home, or the filthy spray hose could leave smudge marks on corners as it is dragged around a yard and home's exterior. Back in the days of smelly pesticides you also could tell quite easily when the spray truck was nearby, because the oily residues and buildup on the tank, hoses, and storage lockers was very, very noticeable. Fortunately nearly all of the products today are nearly odorless and without the oils and solvents, so that helps a bit.

You should clean a tank when using it for different products that might not be compatible for some reason, or where residues from one product could be harmful to things when a different product is used next. For example, some herbicides could be active at extremely low concentrations, and using a sprayer for weed control and then switching to an insecticide and spraying plants or lawns might result in damage to the plantings from the lefover herbicide. I occasionally get the question about using a repellent insecticide and then following it with a non-repellent in the same tank, and whether this would continue to leave some repellency to that next tankful of material. While this is not impossible, I believe that the tiny amount of spray mixture left in a properly emptied tank would be so diluted in the next tankful that it should have little repellent effect.

We do use wettable powders and microencapsulated and other dry formulations that are mixed with water for application, and these materials end up as "suspensions" of the particles in the water. This promotes the chances that over time those particles will build up on filter screens or inside hoses and spray wands, eventually diminishing the proper flow of liquids through those areas. These need to be cleaned very regularly, and filters in particular probably should be cleaned thoroughly at least once a week. Over the years I have seen amazing examples of neglect - B&G spray tubes so clogged with crud that there was room only for the cable to slide back and forth, and not for any appreciable liquid to actually flow through. I have seen syphon tubes where the bottom 2 or 3 inches were corroded completely away from sitting constantly in spray liquid, or the tube just filled up with buildup over time and lack of cleaning. You do realize there is a filter in the handle of the B&G spray wand, and this easily gets plugged with material. Regular cleaning and replacement of parts as needed will improve everything, including allowing that equipment to perform as you expect it to.

Cleaning the outside should be on an as-needed basis, but frequently enough so that no buildup of stains or powdery residue is visible. Some people probably have a higher tolerance for filth than do others, so a good policy would be to have weekly inspections of each vehicle done by someone other than the driver. Maybe hand out a $10 bill to the route tech whose vehicle is the cleanest that week. Univar sells several brands of cleaning products designed just for this, as well as for running through the tanks and hoses and sprayers. One is Neutralize (Becker), which comes in both dry and liquid forms, another is Nokomis 3 (Mar-Len) which is liquid, and a third is called Tank Cleaner (Cleary). All seem labeled similarly. The product is diluted in the tank with the labeled volume of water, the pumps are turned on and the material is circulated throughout the system by spraying it back into the tank. This also allows you to carefully spray the interior of the tank to remove any pesticide residues clinging to it, and to get them into the cleaning solution. The Nokomis label may be the most broad of these three, with directions also on using it for cleaning of the vehicle bed and storage lockers as well as outside surfaces of spray equipment.

Now, just what to do with this cleaning solution once you are satisfied the job is done is a good question, and I always direct people to their local County regulatory agents for advice. The product labels may say one thing, but regulatory people may have their own thoughts in their jurisdictions, so do speak with them. Most often the cleaner labels tell us to dump the rinsate out onto a "non-crop" area, meaning some bare dirt place. I don't particularly like this advice. Another idea is to spray it out onto a surface where you could legally have applied whatever pesticide was in the tank. This is a good reason for keeping the volume of that rinsate to a minimum. The Nokomis label states it can be left in the tank and just used with the next tankful of water for your next application, as long as whatever pesticide was removed from the surfaces is okay to do in this manner. But, we have to treat it as a solution with pesticide in it, and dispose of it legally and responsibly.

As far as dish soap, I think you should avoid this for interior tank cleaning. This is a good way to create massive amounts of foam that are difficult to deal with. For some things dish soap could be okay, say for washing the outside of a hand tank or spray wands. But, getting it inside is begging for foam. A cleaning agent based on ammonia may be better, and of course always wear gloves and eye protection when washing equipment with pesticide residues. There are some cleaners that claim to "neutralize" the actual pesticide active ingredients, insinuating that the molecules are degraded to non-pesticides. I have talked with knowledgeable people who say this just ain't so, but that these cleaners are simply removing pesticides that tend to cling to surfaces.

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QUESTION:

What is the residual of Tempo SC and Suspend SC insecticides?

ANSWER:

Like the weather forecasters, it pays to talk in really vague ways when trying to pin down just how long an insecticide active ingredient will last. There are just a lot of variables that can affect that active ingredient, and different chemical families may behave in different ways. For example, the old organophosphates and carbamates (diazinon, dursban, malathion, etc.) were highly susceptible to degradation due to the pH of the water used to dilute them, or the pH of the surface they were applied to. They also were very susceptible to rapid breakdown when exposed to UV light or when retained in just water. The same chlorpyrifos that might last 15 years in the soil under a house for termites could disappear within a few days or weeks when applied outside for ants or fleas. A lot of active ingredients of pesticides latch onto organic material, so soils rich in organic matter might tie up the active ingredient so that little of it is available to the passing bug or to weeds.

Synthetic pyrethroids, however, are much less subject to degradation from these environmental effects, but they still degrade fairly quickly. This is our two-headed dragon, and the loss of persistent insecticides was demanded by those opposed to our use of them due to fears that the active ingredient that hangs around too long can also be more likely to travel off site, and this fear does have some justification. Because pyrethroids can possibly be very toxic to aquatic invertebrates at very low levels, you now are seeing states implementing regulations regarding the use of these materials wherever they may get into surface waters. Another consideration in all of this is that "residual", for our purposes, really refers to how long it lasts and still is effective in some manner for pest management. The molecule could be detected on a surface long after enough of it has degraded so that it no longer kills the roaches or fleas or other bugs. Since chemicals degrade by a "half-life" - a bit at a time - they do not just suddenly blink out of existence.

So, with this long winded preamble, what is the answer to your question? At a seminar one time, where a few of our respected university consultants and researchers were present, the comment was made that it would be surprising to find any of the pyrethroids, used outdoors, to give more than 2 weeks of residual effectiveness. This obviously is open for argument, and there are ways to lengthen that residual by different formulations. For example, placing the active ingredient within a granular material could protect it from the elements, allowing it to escape more slowly, and for this reason one vendor states their granular pyrethroid gives up to 3 months of effectiveness. The a.i. could be contained within microscopic porous capsules - microencapsulated formulations - protecting the a.i. from water and other elements and extending the residual. You could apply the material indoors or within protected crevices around the exterior where water and sunlight do not affect it directly, adding to its longevity.

Certain surfaces - porous, wood, concrete, alkaline, shiny - can all have their effect too, on how long the a.i. lasts or how available it is to the passing bug, so we keep that in mind and use a formulation best suited for that surface. In this area too is the fact that spraying insecticides onto greasy surfaces, such as in many kitchens, is going to seriously harm the effectiveness. Grease just ties up active ingredients so they are no longer available. Sanitation and cleaning thus have another reason for helping us in pest management.

I myself also believe that where the repellency of pyrethoids works to our advantage there may be a repellent effect long after the killing effect is gone, such as the ability to keep spiders off surfaces that were treated many weeks earlier. But, if we keep our experts' thoughts in mind, we probably should not plan on having these active ingredients (and Tempo and Suspend are both pyrethroids) lasting more than 3 weeks or so. I know darned well I am going to raise the hairs on the backs of the necks of some manufacturer representatives with this answer, but we'll still toss it out there and see what jumps on it.

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QUESTION:

My customer said she is getting small holes in the front of her T-shirts. She brought one down from Virginia, and after washing it saw holes in it. Funny that they are all in and around the same spot near the stomach area. These shirts were brand new from a major store that starts with a "W". Perhaps moths?

ANSWER:

I really, really doubt that insects are going to be the problem here, since fabric pest moths and beetles feed only on wool fabrics, or possibly on cotton materials that are badly stained in some manner. It is unlikely that T-shirts from the Big W are made of wool, and cotton or cotton / synthetic blends are just not tasty to insects. I would say it is much more likely that the fabric itself had some defect in it that was then brought to light with the washing, such as a separation of the weave in that area. But, what the heck. I'm an entomologist and not a clothing inspector, so I really don't know what kinds of defects might occur in fabrics like this. Not to denigrate clothing from the Big W, but it probably is relatively inexpensive and mass produced, so possibly more open to lower quality. Personally, I am not certain I own a T-shirt myself that doesn't have holes in it, a fact my wife points out to me on a regular basis.

My dad always taught me as a boy not to touch my clothing after handling car batteries until I washed my hands. Seems the acid in car batteries was pretty good at eating holes in your clothing. What she is experiencing sounds more to me like a reaction to some chemical. Why it would be occurring in several different shirts but always in the same location on the shirts is a wonderful mystery, but she may be able to think about this and come up with some connection. Something else she wears or applies to that area may be contacting the shirts and causing this problem in that area. But, I really do not think it has anything to do with insects, and I advise NOT spraying "just to make sure" if you have not actually seen any insects that could cause problems to fabrics. The proper action, if she presses you to do something, would be to place monitoring traps around the area to capture moths or beetles or any other insects. This could be either pheromone traps for the appropriate insect pests or simply insect glue traps placed where they won't get stepped on.

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QUESTION:

We are in Arizona, and subterranean termites are my concern. One of our technicians has been asked a question on the state exam that we have not been able to answer. How much moisture is required in wood before termites eat it? They give multiple choices like 13, 17, 25%, etc. Do you have a answer on this?

ANSWER:

Well that's a darned good question, and unfortunately I don't have a darned good answer. I looked in a variety of references and for the most part struck out. But, I did come across one abstract from a study of the survival of subterranean termites in woods with varying levels of moisture, where the termites were confined to the wood and could not return to soil. In this summary it was shown that at a wood moisture content of 20-24% half of the termites survived for up to 12 days, and the rest died earlier. When the moisture content was maintained at 30% the termites managed to survive for up to 6 months, and they concluded that wood with a content less than 24% was inadequate to sustain subterranean termites, and that at least 30% moisture content was necessary to keep them alive for 6 months or longer.

Now, that may or may not answer your question, since you asked about the moisture content needed for subterranean termites to "eat" the wood, and that is very different. A normal subterranean termite colony has workers maintaining contact with the soil, and replenishing their body fluids on a constant basis. This was apparently the problem for those termites in the study above that were confined to wood of 24% or less - they lost body moisture faster than it could be replaced with the low moisture content of the wood. But, when the workers can quickly return to the soil they replenish their body fluids and thus can work on wood that may be much lower in moisture content. In addition, the workers may bring moisture up to the wood to keep it wetter than it was originally, so relatively dry wood (moisture content below 20%) could very well be susceptible to attack by the termites.

We know that drywood termites can survive in very dry wood - moisture content from 5-12%, and that decay fungi generally rely on wood that has at least 20% moisture in it. We also know that the decay fungus Meruliporia (Poria) incrassata can develop a root system that also brings water from the soil below up onto otherwise dry wood, enabling it to move its destruction into areas that were not previously wet. Dampwood termites also are now known to be able to add water to their environment to keep the wood in a very damp condition.

Hopefully you can determine the correct answer from this, and depending on just how that exam question was worded the answer might be that it takes wood moisture content of 30% for long term survival of the termites, or they could attack wood with a much lower moisture content initially, as long as they can continue to move to and from the soil.

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QUESTION:

I have heard of using vacuums for initial German cockroach and bed bug cleanouts. Will any good HEPA vacuum work for this, or do we need to stick to models marketed to our industry? This would seem to be a very effective means of population reduction, but what the heck do we do with all the live roaches/bedbugs we now have contained inside the vacuum?

ANSWER:

This is a timely question, since just yesterday I attended an NPMA program that introduced their new "Draft" version of their Best Management Practices for bed bugs. Given the difficulty of this pest and the many ways that PMP's are going about controlling it (some with success, some not) our industry leaders feel there is a need to develop a comprehensive and consistent protocol for successfully dealing with The Common Bed Bug. Within this document they address, in addition to nearly every other aspect of bed bug control, the use of vacuums, recognizing that large numbers of the insects and many of their eggs can quickly be removed at the outset of the effort, and eliminating the need to kill them in any other way. The vacuum also will remove a lot of the bed bug clutter, such as shed exoskeletons, and make things easier to see from then on.

Their recommendation is to use a vacuum with a HEPA filter that will retain even the smallest of dust particles, thus reducing the level of bed bug contaminants that become airborne. Disease is not necessarily the concern here, but it is likely that allergens are associated with bed bugs and their parts, just as they are with roaches and rodents. In addition, the recommendation is to use a vacuum that is marketed to our professional industry for the purpose of pest control, rather than an over-the-counter vacuum that may not meet our specific needs. The vacuum should have the appropriate attachments to allow it to get into tight corners, edges, seams, and crevices, and should bed physically scraped across surfaces to remove the cemented eggs as much as possible.

They conclude the information on vacuums with the statement only that the "bags" should then be placed within a sealed plastic bag and discarded. This suggests that the proper vacuum would not be a cannister style, where the plastic cannister is emptied and used repeatedly. Getting all of the bugs and eggs out and into a plastic bag successfully would be difficult. I admit I am not familiar with all of the HEPA style vacuums, but do know that some of the vacuums carried by Univar, such as the Atrix Omega Green Supreme IPM HEPA Vacuum are designed for insect management and have disposable bags. Planning on having the turbulence of the vacuum kill all of the bugs would probably be pretty optimistic, and the eggs likely wouldn't be harmed much at all, so keeping them contained and disposing of them in the trash bin would be better. I have heard some people suggest putting an insecticide dust within the bag or cannister, but I am not comfortable about the legality of this.

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QUESTION:

What if any are the natural predators of bed bugs? Thank you!

ANSWER:

A fairly large number of other arthropods are known to feed on The Common Bed Bug, but none of them has ever shown the ability to reduce a population of these bugs once they are inside a structure. And, introducing another bug to someone's home in the hope that it will feed on the unwanted bugs is generally unacceptable to most people. This is especially so when we consider what some of those predators are. These include a couple of spiders, wind scorpions (solpugids), a number of species of ants including fire ants, and a couple of assassin bugs. Releasing a population of any of these predators into a bedroom is just not going to set well with the customer, and since the bugs hide so well and breed so quickly, there really aren't going to be positive results. There is even some anecdotal evidence that American roaches and House mice feed on bed bugs, but again only in low numbers if at all.

This is one more reason that bed bugs are difficult to control - we are extremely limited in IPM opportunities for them, and just letting nature take care of itself does not fit with this pest. I heard it from a reliable source that one state had a brochure available for homeowners, offering guidelines for dealing with bed bugs, and one suggestion was to "eliminate food resources". Clearly this is not going to work for bed bugs, since it is the people that are the food resource, and starving the bugs to death by leaving the home is not effective, since the bugs can survive up to 1 year without feeding. It stands to reason that with a problem such as this there is going to be a lot of misinformation available, particularly on the internet. So, you probably will have people tell you that predators and parasites would do an effective job in bed bug elimination, so why use those dangerous pesticides? We can counter this with accurate information and education.

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QUESTION:

I understand that Avitrol is no longer available since it has closed. I am wondering if this is still legal to use in the state of NY. I am having a bird issue in western NY and I was looking at implementing a program at the location. Can you please advise?

ANSWER:

Yes, this is true, and it was announced by Avitrol Corp. back in October 2010 that it would be voluntarily closing its doors permanently on October 31, 2010. No more product is available from the manufacturer, and suppliers likely have a dwindling supply left in our stocks. But, according to the letter from Avitrol the EPA agrees that all product already in distribution or the hands of end-users may be used according to the Label, so no one is stuck with product they cannot use. I honestly am not sure of the status that Avitrol had in New York in the first place, but if it was legal to use it there prior to the shutdown of Avitrol company, then it should still be legal to use now. You might give your local Univar office a call at 1-800-888-4897 to make sure of this, as they definitely would know the status of this product.

One alternative that is very acceptable, even to pigeon lovers, is OvoControl P, which Univar also carries for distribution. You may already be familiar with this product, but it is essentially birth control for pigeons, acting temporarily to prevent them from successfully producing viable eggs. The birds are not harmed in any way, so OvoControl has been embraced by animal rights groups as an acceptable and humane method for reducing the numbers of these public health pests. It must be fed to the birds on a regular basis to maintain the effect, and it does not cause any birds to leave an area where they are not tolerable, so finding another method for resolving the immediate need of removing the birds is necessary.

This is where physical devices come into play, and once installed the netting or wires or spike strips will continue to keep birds off of those surfaces for many years. It definitely is higher maintenance initially, and thus a higher cost to the customer, but it's sort of "pay me now or pay me later". If all that is accomplished is to scare the birds away from a site, it is inevitable that more birds will be back, possibly very quickly. Univar also carries a major lineup of bird control materials.

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QUESTION:

IS WHITE POCKET ROT A FUNGUS?

ANSWER:

White Pocket Rot is indeed caused by a fungus, but it is not a "decay" fungus, from what I learned at seminars years ago, taught by a wood products expert from the University of California. This expert told us that "Pocket Rot", which is seen as a great many evenly spaced but very small pockets or holes in wood, each hole lined with white, is a fungus that grows only while the tree is still standing. It does not continue to grow in milled lumber and is not a decay. However, sometimes there can be a really extensive amount of this pocketing inside the wood, and obviously this could cause a lessening of the strength and integrity of that wood. If it is used in a place where structural strength is a concern, wood that is heavily laced with these little white pockets would be weaker than wood without it.

There also is a decay fungus called "White Rot", different from Pocket Rot. White rot, again according to this wood expert, is only in hardwoods, not softwoods such as fir or pine. White rot grows relatively slowly, unlike the Brown Rot of softwoods that can grow extremely fast if conditions are perfect for it - wood, warmth, and water. At a seminar this expert was once put on the spot, and asked how fast wood decay could develop. In other words, how quickly could sound wood with no problems progress to decayed wood that has lost its structural usefulness. His answer was pretty interesting. He said that if the proper conditions were suddenly to occur, it could take as little as 4 months for substantial loss of integrity in that wood to occur. So, if a toilet were suddenly to develop a leak and create constant moisture on the wood below, it could be only 4 months for that wood to need replacing.

Another kind of fungus that we commonly see on structural wood is generally referred to as "blue stain", and again this is NOT a decay fungus. But, the growth of this bluish staining fungus does indicate that moisture is present on that wood, and therefore the conditions are appropriate for other more serious fungi to grow as well.

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