Dear fellow beekeepers
I have examined the 1996 Extoxnet bulletin on
toxicology of fluvalinate (the generic name for the active ingredient of
ApistanŽ, Mavrik, and several other branded commercial insecticides),
main info used in registration of this insecticide/miticide.
Severeal wise beeks have outlined the real world of 'active
ingredient' bought cheaper and then administered by home-made dispensers.
Needless to say the old line applies 'OK only if used according to label',
and I would strongly discourage expts with novel routes, except with expert
advice and preferably an actual research plan with someone like Blane.
Coming to the active ingredient called generically fluvalinate, it
is stated to be of the chemical family 'pyrethroids' i.e. its molecular
structure is similar to those of the natural insecticides found in the
famous African daisy _Pyrethrum_.
However, it is substantially different from natural pyrethrins. In
particular, it contains 4 halogen atoms - 3 fluorine atoms and one
chlorine atom - covalently bonded to carbon. This is a major drawback,
on the experience with such compounds to date.
Such carbon-halogen bonds are very unusual in nature (and
when they occur are typically toxic e.g. some natural antibiotics). The
general drift of info accumulated since Carson's far-sighted 'Silent
Spring' (1962) has been an increasing variety of disconcerting biological
harm from such compounds. Organochlorines are, broadly speaking, bad news
- especially when chronically absorbed. Organisms generally lack enzymes
to metabolise them, and bioaccumulation is the general rule. The Extoxnet
bull lacks info on tests for such possibilities with fluvalinate. The
stated rapid excretion is not the same as evidence on actual residues in
the body.
The specific statements in the infosheet tend to read reassuringly,
with the exception of high toxicity for fish and aquatic invertebrates
(which would not obviously be exposed by use in beekeeping generally, but
might be in some circumstances) . But my dozen years on the Toxic
Substances Board taught me to distrust such claims by the chemical
industry. Numerous pesticides got legal approval on the basis of such
soothing reads - forged by Industrial Biotest Corp, whose top executives
served years in gaol upon conviction for faking these "results". The
chemical industry is, as an historical tendency, a refuge for crooks. I
could recount many detailed direct experiences consistent with this general
pattern. Therefore, I for one disbelieve that fluvalinate has been
properly tested or that the summarised claims are reliable.
My personal inclination would therefore be to disparage the concept
that our beekeeping should adopt chronic - tho' not continuous -
administration of any such organohalide compound to our bees.
The only statement about bees in the bull is:
> Fluvalinate was not toxic to honeybees
> exposed to residues left on cotton leaves after application of
> unltralow volume (ULV) and emulsifiable concentrate (EC) formulations
This is a very different mode of exposure from what
prevails in a hive with strips of Apistan amongst the bees for a week or
two.
The present note is intended to be mainly a brief interpretation of
the Extoxnet bulletin for those unfamiliar with the relevant science.
However, I would like to add a brief vague tentative conclusion.
The appraisal of the _Varroa destructor_ threat is truly complex.
The first significance of that complexity is to increase the demands on us
for sustained politeness in discussing the issue. In this matter, more
than in most, honest disagreement is possible; that someone disagrees with
you, especially if tentatively, is no excuse for cutting up ugly and
uttering personal abuse.
Secondly, the relevance of expertise increases as technical details
are deemed to be of importance. This will tend to cost money, and indeed
those like me who give it away will be viewed as suspect by some.
For 3 decades I have tried to interpret for the public problems
such as 2,4,5-T and genetic engineering. I can tell you no specific
problem has ever seemed to me so genuinely vague & complex as this varroa
question, so I am far from dogmatic about whether the hazards of
fluvalinate to bees and other spp are justified by the benefits.
What I will be dogmatic about is to condemn the universal official
neglect of promising R&D projects to control varroa by possible parasites,
volatile common chemicals e.g. formic and other organic acids, etc. If
anything the synthetic-chemical industry is more influential than ever.
R
-
Robt Mann
consultant ecologist
P O Box 28878 Remuera, Auckland 1005, New Zealand
(9) 524 2949
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