Allen,

In a recent communication about the evolution and spread of pyrethroid
resistance in Europe the following comment was made:

> It is thought that beekeepers in Italy used a liquid agricultural
> formulation of Klartan, absorbed on a porous piece of wood or similar
> to combat varroa. Because there was no control over the amount (of active
ingredient)
> applied, this practise inevitably gave rise to resistance, not only to
> Klartan, but to the whole class of synthetic pyrethroids including
> Bayvarol and Apistan.

You replied:

>This is often repeated, but is at best an oversimplification, and at worst
a lie
>that those who sell a penny's worth of chemical for $2 don't mind having
>repeated often.

That is a glib response, offensive not only to me but to the well-respected
bee researchers from Germany, Italy, Switzerland and France as well as the
hundreds of beekeepers who carried out the trials which proved this to be
the case. Research such as this cannot be dismissed because there was some
involvement from a chemical company (Sandoz, as it was). Especially when you
don't seem to know or care about the reality of this situation - even
'though I have posted this on the LIST some time ago. I am really surprised
at you.

The statements which John Burgess mentioned originally are far from rhetoric
from a "chemical company". There is solid foundation to these claims.

In the early 90's as the then Technical Manager for Sandoz I coordinated an
international team of independent, reknown experts on a project lasting 5
years, investigating the emergence of pyrethroid resistance in Europe.

It had been openly stated by many people, incuding Sandoz, way before the
conception of APISTAN that a pyrethroid-resistant mite strain would
inevitably evolve. Klartan/Mavrik was being used for years before APISTAN
was developed.

Providing there is a lage enough selection pressure and the benefits
outweigh the costs, organisms mutate through natural selection. FACT.
Any and all treatments to control "pest" populations represent a type of
selection pressure. FACT.
Because of its many benefits of bee safety, low residue profile, proven low
mammalian toxicity profile etc etc  Apistan (or illegally Klartan/Mavrik)
was and indeed still is the most popular hive treatment for varroa
worldwide. Incredible selection pressure. FACT.

When the first reports of "Apistan inefficacy" arose in 1992 in Italy,
APISTAN had only been in use for one year. In the regions where the
"inefficacy was most widely reported APISTAN was not used at all; the
agrochemical Klartan, however, had been used for 8 years, on balsa wood, on
cloth and anything else to hand.

Recipes for using Klartan were common in Europe. In Spain they recommended a
5% soltion in water; in France it was 2% solution. This didn't work in
Southern Italy after a while and so the dose was increased to 50% and then
in many cases, to 100% neat. Low efficacy after 8 years. FACT.

When this inefficacy started to show up in Northern Italy, where APISTAN had
been used for just 2 years the cause was not so clear. However, the Italians
were able to trace exactly the spread of a resistant strain of varroa along
the main routes of migratory beekeeping from the North to the South of
Italy. Colonies are taken to the South for the winter and brought back North
in Spring, carrying with them the resistant varroa from the South. FACT.

It is noone's fault that resistant varroa emerged, it is a natural process
of evolution. The uncontrolled dosing did however greatly speed up the
process. If there is an increase in the LD50 (the level of a substance that
wil kill 50% of a population) by tenfold, ie a resistance factor of 10,
generally one can say that a resistant strain has emerged. In the case of
varroa from Southern Italy the resistance factor was more than 400.
Definately resistant. It was also shown scientifically that this resistance
is conferred to other related pyrethroids such as flumethrin and
acrinathrin. FACT.

The dose/response curves obtained for this resistant strain are distinct.
Wherever resistance was monitored throughout Italy and later in France,
Germany, Switzerland, Austria and Eastern Europe. the exact same curves are
characteristic. This most probably means that the resistance has arisen only
once in Europe and spread from one focal point. The slow speed of apparition
in neighbouring countries suggests Italy to be the focal point. If the
dose/response curves were markedly different for the different populations
examined then we could expect there to have been separate evolution. So far
all populations examined (coordinated by Vita since 1997) have shown the
same pattern and seem then to have the same origin.

There will always be a risk of any pest organism developing resistance to
the treatment. It is why several different types of treatment should be
used. If there is resistance to one treatment, perhaps the second or third
[different] treatment will take out the resistant individuals. Even IPM will
not stop the phenomenon of mutation and evolution in pest populations but
the aim is to keep the resistance to a manageable level, below the economic
damage threshold.

Vita (Europe) Limited is a small UK company specialising in the development
of honeybee disease treatments. We take the concept of IPM very seriously
and unlike the chemical giants who have no time for such small markets, we
are dedicated to improving the health of honeybee colonies, operating
world-wide. Yes, we make and sell APISTAN but we also have other treatments
in registration and in development, many of them natural agents, for EFB,
AFB, mites, chalkbrood and wax moth.

In science and in business I believe there is no room for half-truths. At
Vita our policy is to be open so as to avoid confusion. While many people
may disagree with what we're doing, Vita is not in the business of making a
fast buck. What we do is thoroughly researched and is for the long-term. No
short cuts, no "oversimplifications". Whatever is posted to the LIST from
Vita, we believe to be correct and true.

But, Hey, how can this possibly be true - Vita must be classed as a
"chemical company", right?

Believe what you will.



Max

Dr Max Watkins
Vita (Europe) Limited
Brook House, Alencon Link
Basingstoke, Hants RG21 7RD  UK

Tel.   +44 (0) 1256 473177
Fax   +44 (0) 1256 473179

http://www.vita.demon.co.uk