Small cell size and varroa -- A summary and assessment of current information.

Since varroa has become such a terrible and intractable pest for
beekeepers, many people seek a "final solution" for this problem. The
idea of using foundation with smaller (4.9 mm) cells to reduce varroa
populations has received quite a bit of attention on the internet, if
not elsewhere. I have attempted to find out as much as possible about
this and wish to summarize what I have found.

First, I feel that no treatment that shows promise should be
dismissed. IPM (integrated pest management) techniques are frequently
aimed at *reducing* pests and are often used in combination for
mutual enhancement. Very often these treatments vary in their
effectiveness and have to be supplemented with chemical control
(which also varies in effectiveness).

In order to give this treatment a thorough evaluation I feel it must
be tested in different regions and in different apiaries. It must be
tested side by side with control hives (non-treatment or other
treatment hives). The method of setting up an apiary to test a
treatment can be debated but a significant reduction in varroa must
be shown between treatment and non-treatment hives in the same apiary.

There have been a number of theories as to why this treatment would
work and why it hasn't caught on. The idea that bee supply
manufacturers and research institutions do not want it -- is
erroneous. The cost of tooling up to produce odd-sized foundation is
not that great and would be recouped quickly *if* enough material was
sold. The rollers used to stamp foundation wear out and are replaced
often enough that to add odd-sized rollers could be done fairly
easily. At this point it is already possible to obtain small sized
foundation from Africa and drone foundation from U.S. suppliers.

The theory that changing cell size in the early 1900s caused the
varroa problem simply doesn't hold water. The idea that varroa
probably moved into Apis mellifera hives at the same time as the
experiments with 5.4 mm foundation and therefore these events are
connected is an unprovable conjecture at best. Modern beekeeping was
barely 50 years old at that time and there were so many changes
taking place that cause and effect connections simply cannot be
feasibly drawn at this late date.

The bottom line, however, is that it doesn't matter. If a technique
works, a theory for why it works is not necessary and can be
generated at some later point. In my opinion, the following theory is
more plausible: Varroa prefer larger cells and in the species Apis
cerana they are seldom found in the worker cells. The worker cells of
Apis mellifera are larger than cerana, so they are more attractive to
the varroa. But this is good, because if the varroa can be driven out
of the worker cells by whatever method, it is possible that the
colony will be able to survive the infestation. Furthermore, the
addition of 2 or 3 drone combs to *attract* the mites (to be removed
and frozen twice a month) would constitute an excellent IPM plan.

The notion that this technique is being suppressed is erroneous.
Research institutes are not all beholden to chemical companies. Some
researchers may have received money from corporations but I don't
think this has altered the direction of research *as a whole*. The
USDA is promoting screened bottom boards as a method of reducing
mites. Who makes money off of this? It isn't even a patentable idea,
anyone can make their own device and cheaply, to boot. The blueprints
for the Ontario Pollen Trap were released into the public domain
years ago -- bee researchers have shown a willingness to share new
ideas and are not in this field to get rich, in any case!

Dr. Erickson (USDA) has done some controlled studies of the small
cell size and has reported promising results. He told me that, due to
some problems unrelated to the merit of the study, the wide
publication of his results was delayed. Personally, I am disturbed by
the fact that the two mostly widely publicized studies (possibly the
only ones) have been conducted in southern Arizona. This area has
been infiltrated by Africanized bees and that alone could account for
reductions in varroa populations. It has been reported that the
Africanized bee in South America can coexist with the mite.

It is the bee industry that has demanded and gotten the chemical
controls because they have millions of hives at stake. They want
something powerful and effective that produces quick and observable
results. There are many problems associated with chemical control of
pests and this issue will never go away. The pesticide treadmill is
one we may never get off. The whole genetic engineering industry uses
this as a primary justification for their work, as does the organic
farming community. Everyone wants to get off of pesticides, because
they are ruining the air and water of this planet. No one wants to
see the cancer rates continue to rise. The problem is that we are
addicted to these techniques and cannot go off "cold turkey".

In order for a large scale experiment to be conducted there has to be
*credible* justification. The promise of widespread adoption is not a
requirement. It is doubtful that commercial beekeepers would adopt
the technique of adding and replacing drone combs twice a month, and
yet this is being tested by a number of organizations. It is true
that the replacement of all the combs in all the hives would be a
staggering expense.

I don't think all the combs would have to be replaced. Only the brood
area has to be modified. This could be a problem for all beekeepers
who do not use queen excluders. For those that do, the new combs
could be drawn in the supers and the honey extracted. Then the queen
could be confined to one or two boxes with an excluder and forced to
lay in the smaller cells. The old supers could still be used for
honey storage, above the excluder. (Many beekeepers simply don't
believe that they could incorporate excluders into their operation.
It would also be an additional expense.)

The biggest problem facing beekeepers today is the sagging price of
honey. If honey was worth more, then labor intensive or expensive
treatments would be more feasible. The reputation of honey as an
attractive product has to be reestablished and promoted. The thinner
the profit margin, the less eager any beekeepers are to take risks.
Small beekeeping associations are in the best position to sponsor or
conduct experiments. It is essential, however, to be conservative in
reporting results. Exaggerated claims or unrepeatable conclusions
will only generate prejudice and prevent the truth from being
discovered.

Please note:
The opinions expressed here are mine alone and are not intended to
reflect Cornell University policy officially or unofficially. All
time and effort spent researching this topic was my own and not
underwritten by my employer. I grant permission to quote or reproduce
this document provide attribution is given as follows:

Peter Borst. Ithaca, NY. <[log in to unmask]>