Two Decades of Varroa, Part I

Bee Culture (October) Vol. 135 (10): 19-21




Dr. Malcolm T. Sanford


I have been informed that my pending visit to Australia will be like a beekeeping journey back in time.  “Down Under” in “Oz” beekeepers continue to enjoy being free of beekeeping’s greatest nemesis, the Varroa mite (Varroa destructor).  I look forward to seeing and experiencing beekeeping as it once was in the United States, a simpler time, when the honey bee was a more “wild” (feral) animal that could look after itself without being actively aided by the beekeeper.  For, truthfully, this insect is now a much more “domestic” animal in most of the world than previously because of this mite.


In recent years, there appears to be a resurgence of hobby and sideline beekeeping according to my sources.  I have seen corroborating evidence of this by seeing who is in attendance at various association meetings, and have recognized the emergence of two populations of beekeepers, which I characterize as before Varroa (BV) and after Varroa (AV).  The AV folks really have no idea of what beekeeping used to be like for us that are in the BV community, and shouldn’t, for the landscape has inalterably changed with introduction of the Varroa mite, except for a few places like Australia.


Tempus fugit (el tiempo vuela) “time flies” as this month (October 2007) is the twentieth anniversary of the first detection of the Varroa mite in North America.  As one of those on the front lines at that time, I have seen and felt the invasion first hand.  It is worth looking back on this singular episode and subsequent events in a series of articles in order to get a historical perspective of what beekeepers have gone through in the last two decades.  Much of this one can still find in my old, but still live, web site at the University of Florida, the pages of the Apis newsletter, and now in my site, The Apis Information Resource Center and associated “lenses” at


I wrote the following in the Apis newsletter, then published by the University of Florida: “Introduction of the Asiatic bee mite (Varroa jacobsoni) is a nightmare come true for the North American beekeeping industry.  Even as I write this, many persons are in a state of shock.  As of this date (October 20, 1987), some nineteen of Florida's sixty seven counties have had positive finds.  Latest information is that there has been confirmation of the mite's presence in the states of Pennsylvania, Ohio, Illinois and Wisconsin.  The great majority of finds so far have had some kind of Florida connection.

“As a first step in attempting to assess the situation, the Commissioner of Agriculture on the advice of Varroa Mite Task Force and the Honeybee Technical Council has placed a two-week moratorium on bee and beekeeping equipment movement.  This is to try to get an idea of the mite's present distribution.  Emergency teams made up of Florida bee inspectors and APHIS (Animal Plant Health Inspection Service) of the U.S. Department of Agriculture are now combing the state for infested colonies.

“It is extremely important to ensure that Varroa is not confused with the tracheal honey bee mite (Acarapis woodi), first found in 1985.  There has been and continues to be a great deal of controversy about the latter mite which lives in the breathing tubes of bees. It is difficult to find and the damage it inflicts on colonies is a matter of great debate.  At present there is no legal chemical control and experiments on a number of aspects of the biology and control of this mite are continuing.  Both the general and beekeeping public, however, may think the present mite crisis is a continuation of the tracheal mite affair. THIS IS NOT SO!

“The Asiatic bee mite (Varroa jacobsoni) is another story entirely.  There is near unanimous support that it is potentially the most serious pest ever to threaten U.S. beekeeping.  As evidence for this, consider that both Canada and Mexico have sealed their border to U.S. bees because of the recent finds.  Reports from other areas where the mite has been introduced, especially temperate climatic regimes, indicate great losses of colonies have occurred”2

The next month, I reported the following: “On November 9, a Varroa Mite Research Work Group was created, chaired by Frank Robinson, Secretary- Treasurer of the American Beekeeping Federation and retired Professor of Apiculture from the University of Florida, the purpose of the group is coordination of research, regulatory and extension activities related to the Varroa mite situation in the state.  The following is a brief summary of the research activity going on in Florida at the present time:

“To address the short-range problem of bee movement around the state, which is a top priority, Drs. Harvey Cromroy, IFAS (University of Florida) and Everett Nickerson (Methods Development, Division of Plant Industry, FADCS) have initiated paperwork which is being assembled in Tallahasee by Jim Downing, FADCS to request a Section 18 Specific Exemption label for the miticide, Amitraz.  This is to develop the necessary information on the material's dosage (how much material should be applied and in what manner), efficacy (how many mites are killed during treatment of a colony) and residues (how much miticide might get into bees, honey and wax).

“In conjunction with this effort, Drs. Cromroy and Nickerson, with the help of Dr. Elton Herbert, Beneficial Insects Laboratory, Beltsville, Maryland, have embarked on a screening program to examine a number of different chemicals now in use in Europe and elsewhere to control mites.  These include Apitol, Apistan, Folbex VA, and Varamit. In addition, they will also be looking closely at the use of various dusts, which on a prelimary basis appear to be effective as mechanical controls for mite populations, as proposed by Dr. William Ramirez, University of Costa Rica.”3

In spite of all the regulatory effort noted above, it was too late.  The Varroa mite literally was everywhere and no amount of expense or effort would limit its spread.  It still remains incredible to me the rapidity of the mite’s spread; it seemed to spring up everywhere once first detected.  The above paragraph contained something extremely significant, the beekeeping industry was embarking on a road to chemical treatment.  This paradox was not lost in my statement/question in December 1987, “Pesticide Use Inside Beehives?”4:

“Some years ago the above statement would have raised more than a few eyebrows.  Many questions by beekeepers each year concern using pesticides to rid colonies of invasions by ants, wasps, wax moths and on rare occasions, beetles.  No answers, however, ever indicated pesticides were to be used near colonies, much less inside them.  The closest to this was wax moth control which involved fumigating empty supers with pesticides.  To most beekeepers, pesticides were an anathema, responsible for killing untold numbers of colonies in agricultural and urban areas, and agriculturalists and mosquito controllers were considered a collective enemy for using them.

“The worm has turned.  With detection of the tracheal mite and now Varroa jacobsoni (the Asian honey bee mite), the hue and cry for pesticide use within the hive by beekeepers has reached a crescendo.  This irony has not been lost on some of my colleagues, who've been plagued with beekeeper complaints about pesticide use over the years.  Not that pesticides don't have a place in control of mites, but the all-too-prevalent view that they are somehow a ‘magic bullet’ which will mean the end of the pest and a return to business as usual is a bit disconcerting.

“This philosophy may come from the experience with Terramycin ®, which is now routinely used as a preventative treatment for American foul brood (AFB).  As successful as this has been, it has not entirely eliminated the disease.  Most bee inspection services are in place today specifically because American foul brood is still a threat.  Hundreds, perhaps thousands, of colonies nationwide are burned each year to eliminate American foul brood reservoirs.  Many beekeepers emphatically state that if they see a colony with AFB, they immediately destroy it themselves, even in states like Florida where an indemnity is paid if a bee inspector burns a colony for AFB.

“It's important to realize that the management system to control AFB did not come about overnight. It is the result of a good deal of learning on the part of beekeepers, scientists and others since the 1920s, when thousands of infested colonies were routinely burned in an effort to control infestation.

“And as effective as it appears to be at present, use of Terramycin® is not without possible future complications which run the gamut from contaminated honey to an antibiotic-resistant bacterium strain.  Fortunately, the causative organism, Bacillus larvae (editor’s note:  now named Paenibacillus larvae larvae), has not shown resistance to Terramycin®.  Routine treatment for American foul brood also means that the line between bees which have some innate resistance to the disease and those that are susceptible becomes fuzzy.  Nevertheless, colonies continue to be routinely treated despite proof that resistance to the disease by several mechanisms does exist within some bee populations.  Thus, should Paenibacillus larvae larvae eventually become immune to Terramycin®, bee populations which are resistant to AFB might be difficult to find.

“In Varroa control, resistance by mites to chemicals improperly used and/or applied has already been established, particularly phenothiazine in Japan and amitraz in Israel. This means that pesticides must be used far more judiciously within the colony than is currently done with Terramycin or resistant mite strains will quickly develop.”

Looking back on these statements reveals how prophetic they were.  The beekeeping community adroitly clambered aboard what many have called the “pesticide treadmill” in a futile effort to find a “magic bullet” for Varroa control.  The first candidate was quickly approved by the authorities on an emergency basis, using Mavrik® (active ingredient fluvalinate) soaked on plywood strips.  I had first seen this technology in Italy in 1989, although the material had the brand name Klartan® in  that country. 

On March 21, 1988, it became no longer legal to use fluvalinate-treated wood sticks. Instead, only plastic strips manufactured to slowly release small quantities of fluvalinate, were legal and had to be used under an emergency compliance agreement with the Division of Plant Industry.  Apistan® indeed appeared to be a magic treatment and the industry was to get ten good years of use from this material. 

The use of Apistan® did not fully alleviate the fears of many that honey could be contaminated by fluvalinate, which might morph into a big problem for the honey market.  And it in August of 1990, I wrote the following, “It was only a matter of time. The Boston Herald reported that honey from a specific outfit had been contaminated with fluvalinate, the active ingredient in Zoecon's Apistan® plastic strips. Taking this conclusion further, the newspaper then implied that the contamination came from the strips themselves. The facts do not bear this out, the Corporation says, in a packet of information sent to industry leaders. According to the Corporation, it would take some 96 strips placed into a colony all at once to reach contamination levels reported by the newspaper (1.14 parts per million). If used according to the label, Zoecon points out, honey cannot be contaminated using the strips.

“There are a number of ways that honey might become contaminated with fluvalinate.  This active ingredient, also marketed in other products to control insects on ornamentals or turf, may be applied to beehives in many ways.  Plastic Apistan® strips can be left in the brood nest too long.  It is not legal, nor wise, to leave the strips in a colony longer than listed on the label.  Wax and honey contamination, as well as build up of resistant mite populations, are the likely outcomes of this practice. Experience in Israel, where fluvalinate impregnated in wooden strips are often used to control Varroa, indicates the material builds up in wax and possibly honey.  The result of this episode of contaminated honey and the attendant press coverage will be increased testing of product destined for the consumer market.  The state of Florida has added fluvalinate to its honey testing protocol and this will probably be the case in other states as well.”

I, therefore, concluded:  “The message is clear:  all misuse of fluvalinate (that includes at the present time, ANY USE EXCEPT Apistan® strips applied ACCORDING TO THE LABEL accompanying the product) will be sought out by the authorities and is potentially damaging to the beekeeping industry.”5

This sets the scene for the next article on this important historical event in U.S. beekeeping.  It will reveal how among other things, the fluvalinate silver bullet has lost much of its effectiveness to be replaced by even more toxic materials, while at the same time a variety of so-called “soft” chemicals have come on the scene.  In addition, the move toward integrated pest management, something well known in other agricultural areas, will be described.



  1. Sanford, M.T. Apis Information Resource Center,, accessed August 19, 2007
  2. Sanford, M.T.  Apis Newsletter, Volume 5, Number 10 (October, 1987),, accessed August 14, 2007.
  3. Sanford, M.T.  Apis Newsletter, Volume 5, Number 11 (November, 1987),, accessed August 14, 2007.
  4. Sanford, M.T.  Apis Newsletter, Volume 5, Number 12 (December, 191987),, accessed August 14, 2007.
  5. Sanford, M.T.  Apis Newsletter, Volume 8, Number 8 (August, 1990),, accessed August 14, 2007.