Glueboard versus Electrocuter ILTs:

The Professional Debate at (v.6/14/02)
By David Gilbert

My father, Don Gilbert, was the first to recommend to industry that insect electrocuters be kept a safe distance away from open product areas. In 1986, he recommended in a letter to the FDA that insect electrocuters be kept at least 10 feet away from open food containers and food handling surfaces.

Throughout the 1990's, accusations were made against electrocuters by manufacturers who make only glueboard ILTs. They claimed electrocuters "explode" flies and scatter micro particles up to 6 feet away. They claimed to have discovered this. And, that it was so significant that the sun was setting on electrocuters. So far, this has been a very one-sided, propaganda attack of one commercial technology against another. We make both types of ILTs, glueboards and electrocuters. And, intend to search for truth on this issue.

In doing this, since the argument has been so one-sided for so long, I may appear to be prejudiced toward electrocuters. And, to be honest, there may be a bit of truth to that. After all, my father invented the indoor electrocuter. However, he also patented a glueboard trap in 1972. And, trap designs were not his primary motivation, nor is it mine. So, let's begin the debate, the search for truth, and let the chips fall where they may.


To start, you don't need a microscope. Look at electrocuted houseflies yourself. Use a hand lens if you have one, but it is not necessary. Are electrocuted flies basically intact or "exploded"?

Of course, you can find a dictionary definition to argue the use of the word, but you would have to ignore the actual way it has been used in this decade old, smear campaign. It is a word with several different definitions, making it imprecise, and a poor choice for a scientific description of insect electrocution. The accusation has very clearly been that electrocution "explodes" flies to bits. When a person gets hit by lightning, does he "explode"?


Only from an alarmist's viewpoint would the leap to the word "explode" be so easily, so frequently made. This view is microscopic. So, let's get microscopic. Let's focus in so closely that we might imagine small electric zaps to be lightning bolts, but, please, no imaginary explosions. Let's take a different kind of "exploded" view, where (as the dictionary defines it) the small parts are shown, but in correct relationship to each other.

How many potentially hazardous micro particles are on a typical fly? How many are transferred when a fly lands and walks on a surface in a hospital, food plant, or restaurant? How many are in the droplets flies use to dissolve their food before they consume it? How many come out the other end of the fly? Now, how many is it Chicken Little wants us to be so fearful of?

All of these are large numbers aren't they? But remember, these are very small, very very small, micro particles? How easy is it to use such naturally large numbers to make alarmist claims? More importantly, and here's the key, the alarmists' use of these large numbers is selective and selectively focused, as a magician would focus attention while doing a parlor trick.


If attention can be focused intensely enough, exclusively enough, on Chicken Little's rants, no one notices the sky is not falling. If attention is focused on the alarmists' mythological "exploding" flies, it may not be noticed what is actually happening in a real food plant, pharmaceutical laboratory, hospital, supermarket, or restaurant.


What is the micro environment in these places really like? Does it vary by type of facility, location within a facility, management's level of concern? How many whole flies are normally buzzing around these facilities?

The best way to estimate the population of flies is to monitor with professional ILTs. They routinely catch more flies than are seen on visual inspections. Once this number is captured, multiply it by the number of potentially hazardous micro particles on a typical fly. Does this reveal billions of micro particles on the wing in all types of facilities?


Using slow-motion photography, we can see a fly flap its wings exceptionally fast and adeptly. It's been reported that the horsefly can "turn in mid-flight and pursue a passing female at 90 miles per hour."1  Now, how many micro particles fall off a fly when it simply flies over an area? How about when it does an acrobatic loop or maneuvers a small gust of wind (which to the fly and the micro particles it carries may be quite severe)? How many such maneuvers does it make as it cruises back and forth between its favorite places inside and the dumpster outside (or worse)?

Now, don't forget that the electrocuted fly is taken out of the population. The one flapping its wings overhead continues on its' way. How many hazardous micro particles are deposited directly on food processing lines, when flies frolic freely, defecating and vomiting where ever they like? How many when a fly, only one fly, actually lands on and is stuck in an open food container?

Even if the questionable research and accusations approached reality, do properly placed electrocuters eliminate a far greater number of micro particles than the alarmists have been squawking so long and loud about and want us to be so fearful of? What reason is there for such abusive trash talking if electrocuters are doing such a wonderful job, so far superior to having no trap at all? Is the micro advantage glueboards provide actually significant, or not?

Retired USDA researchers, Weidhass and Morgan found that "Damage to the flies from electrocution in the light traps was seen as the separation of some legs from the body and the loss of wings or parts of wings. The majority of flies showed no damage from electrocution....Since it has been reported that small microscopic particles have been detected in electrocution of flies, it may be possible that some of the missing wing parts are a source of these particles because they are singed in the process of electrocution. In practice the small amount of wing material involved would seem to be inconsequential."


Are there instances where electrocuters are needed, preferable, do a superior job? Do glueboards have drawbacks other than being susceptible to dust and humidity? short life? Cost? Hassle? Time consumption? Do glueboards accumulate in garbage dumps? Are they biodegradable? Do they make insect identification more difficult? Are there necessary uses for each type trap under various circumstances? These questions have yet to be asked, much less, answered. How many other questions have yet to be asked?


Have inspectors, all of us, been intentionally misled, tricked into requiring superior equipment to be replaced with inferior gimmicks? If it is true that electrocuters are not allowed in food plants, as has been claimed. Why, then, does the FDA Interpretation give guidelines for their proper use in these places?

Rumors have been spread that, "the FDA has been after electrocuters for a long time."2 Show me the evidence. I believe it's false innuendo on top of exaggeration. The only PhDs in high positions I know, basically, agree with me. However, amazing as it seems, government bureaucrats, even PhDs., can be wrong. We all can. Appealing to authority to prove your point (though often effective) can be a fallacy of logic.3 Let's stick to the facts, the pertinent questions, the scientific debate.

Some moths, such as the ones used in the earliest exaggerated research, fall apart in your hand, no matter how gentle you try to be. Why were these insects chosen and focused on so heavily? Were too many insects used in too small a test chamber? How hard did the micro particle measuring system suck? If a facility has this many insects, is the real problem something other than electrocuters, such as insect inviting lighting or inadequate sanitation and exclusionary tactics?

I am certain there has been misleading information on the trapping efficiency of ILTs from PhDs who don't seem to have any idea what they are talking about or how it is likely to be used/interpreted in the marketplace where claims routinely exceed scientific evidence.

Of course, electrocuted insects, this issue, should be considered, but does the exaggeration appear amazingly early and often, combined with what appear to be other exaggerated or false claims?

Why have manufacturers (who make only glueboard traps) advertised this "exploding" flies exaggeration so heavily? Could it be so they could point at their competition and call them old-fashioned, so their weak designs would appear new and innovative? Are there inspectors who have been so misled as to insist that superior glueboard ILTs be removed simply because it has a classic design (it looks like an electrocuter), but has no electric grid, only glueboards?

As a result of marketing gimmicks presented as educational courses, are there inspectors, and other "professionals", who believe stunning circuitry to be a necessity rather than a gimmick?

Should one who is concerned for our environment and  cannot show just cause for filling up our nation's landfills with "revolutionary" stunning circuit boards, stop promoting them? 

I have not separated the researchers from the corporate advertising campaign because I am not aware of any effort on their part to do so themselves. It's hard to tell where one ends and the other begins (by design?).

If you dig out this research, question the methods, consider the "ballistic" language, investigate the references, what do you discover?4 We need an in-depth look at the bare bones methods and materials and discern what is actually there. We need the help of serious microbiologists from across the liberal/conservative spectrum (I'm sure opinions will vary). They need a better understanding of how professional ILTs actually fit into different micro-environments, pro, as well as con.

Of those of you who believe the research has merit, have you or do you know anyone who has actually investigated the claims in detail? Can you defend the research against real scientific inquiry. If not, it might be wise to take a harder look, to think for yourself. It would appear there has been an ad ignorantiam5 attack against electrocuters. For those of you who believed this debate was over a long time ago, you should wake up, the debate has just begun.

Is it in such debates, in sincerely questioning, struggling, with all viewpoints of an issue, not simply repeating what the "experts" tell us, that true professionalism is born and 60 minutes fiascos are avoided. When confronted with a mirror, do the brave shoot it or polish it and look into it? Of course, we may need to sandblast through several layers of hardened mud first, only to discover a funhouse mirror. The only thing certain in an open-minded search for truth is that we will learn something.


It's not that there is no issue worth discussing. As I mentioned earlier, My father recommended to the FDA that electrocuters be kept at least 10 feet away from open food containers and food handling surfaces in 1986. USDA research6 led the FDA to set the recommended distance at 5 feet. We didn't disagree. We felt there was a need, in some circumstances, for shorter distances and knew a number of inspectors would view it as an absolute. The FDA interpretation remains at 5 feet today.

We have always emphasized eliminating flies as early as possible, before they get into critical areas. I believe there is a real need for electrocuters. I would like a clearer view of the research that exists (how exaggerated is the exaggeration) and better research done. That's why I am calling for serious study.


What is needed is sincere hazard analysis from truly non-partisan scientists, a sincere public debate of reasonable length, and, perhaps, an update of our interpretation, not a Chicken Little inspired interpretation, but a thoughtful, even-headed interpretation. And, I am not referring to the FDA's Interpretation. If professionals do not have their own well considered interpretation, how do you know if the FDA (or other acronym) is right or wrong or somewhere in between?

It is not that there is no issue worth consideration. It's the exaggeration, partisan zealotry, and "ballistic" use of language which explodes things out of any real scientific proportion. "Expert" recommendations today range from, keep them 5 feet away to you can't use a trap that even looks like an electrocuter anywhere in any food facility. There is a need for simple guidelines, but not for simplemindedness.

I don't believe anyone's idea is clear enough at this point to start making people expend large amounts of money changing existing ILTs and their locations as long as existing standards are being met and no real need for change exists. There may be no real problem at all, only exaggeration. However, in new installations, it might be prudent to go by my father's 10 foot recommendation, and, at times, even 20 or 30 foot spacing; especially, when it's easily achievable, the specific circumstances for each trap have been considered, where you are, what you are trying to accomplish, and seriously considering the situation with your brain on and your eyes and ears open.

I hope the FDA would not change the 5 foot rule to 10 feet if it is to be interpreted as an absolute distance through which you could not even roll a cart of packaged product or in which needed exceptions for stored product insect monitoring, etc. are forbidden. Professionals need room for flexibility, for reasonable adjustments to specific situations, to new, better research, and future deeper understanding. It appears the FDA has given us that room all along. Please, read the Food Code (Section 6-202.13) with love for science, not extremism.

Please, enlighten me about any research on this subject (see Footnotes/Links below). E-mail, FAX, or snail-mail me the pertinent info/web addresses. Any information remotely related to this issue (flying insect control, etc.) is appreciated and welcome. Your opinions, input from all perspectives, is needed before a truly professional viewpoint can evolve, which is what we intend to happen here.


If the relatively small number of micro particles reportedly scattered by electrocuters is considered significant enough to warrant more restrictive use, then how much more imperative is it that scientists/pest management professionals get a better grip on controlling the much larger numbers of micro particles being transported around our food plants, pharmaceutical laboratories, hospitals, supermarkets, and restaurants by unhindered flies? If you don't want electrocuters, I've got several glueboard ILTs I'd like to show you, but, first, how's your sanitation, exclusion, strategic lighting?

Debate Under Construction (still in early stages). When quoting, please, note this and the title (which includes the version number (v.Mo/Day/Yr) and the web address where the updated version can be found. BOOKMARK THIS PAGE, the debate will evolve here.

Footnotes / Links

1 Kunzig, Robert. 2000. What's The Buzz? Pest Control Technology Magazine, December 2000, pgs. 88-96.

2 Weidhaas, D.E. and Morgan, Phillip B. 1993. Fate of Houseflies Killed in Gilbert Electrocuting Light Traps. Research sponsored by Gilbert Industries, Inc., Jonesboro, Arkansas, USA.

3 Ad Verecundiam: A fallacy of logic in which an appeal is made to inappropriate authority. In this case, no real authority exists because the fully developed argument is yet to be made, the argument from which such special wisdom in this sphere might be attained. Suggested reading: "Introduction to Logic", Fourth Ed. Copi & Cohen. 1998. Prentice Hall, Inc.

4 Four Research Papers on the Subject for your Consideration:

Ananth, Gopal P., Bronson, David C., and Brown, Jeffrey K. 1992. Generation of airborne fly body particles by four electrocution fly traps and an electronic fly trap. International Journal of Environmental Health Research 2, 106-113.

Broce, Alberto B. 1993. Electrocuting and electronic insect traps: trapping efficiency and production of airborne particles. International Journal of Environmental Health Research 3, 47-58.

Tesch, Michael J. and Goodman, Walter G. 1994. Dissemination of Microbial Contaminants from Houseflies by Five Insect Light Traps. Correspondence address: Dept. of Entomology, 237 Russell Laboratories, University of Wisconsin, Madison, WI 53706, Phone (608) 262-6919; FAX (608) 262-3322

Urban, James E. and Broce, Alberto. Electrocution of House Flies in Bug Zappers Releases Bacteria and Viruses. Kansas State University, Division of Biology/Department of Entomology.

5 Ad Ignorantiam: A fallacy of logic in which a conclusion is supported by an illegitimate appeal to ignorance, as when it is supposed that something is likely to be true because it has not been proven to be false. See, Introduction to Logic, Fourth Ed. Copi & Cohen. Prentice Hall, Inc., 1998.

6 Pickens, Lawrence G. 1989. Factors Affecting the Distance of Scatter of House Flies (Diptera: Muscidae) from Electrocuting Traps. Journal of Economic Entomology, Volume 82: pp.149-150.

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