I said
>> A link missing in this discussion has been the impact of agrichemicals,
>> ....
Peter Edwards responded with
> This came up in a recent lecture by Dr James Cresswell of Exeter
> University. He stated that the combination of neonicotinoids and nosema
> was only at problem at ~ 70 times the field realistic dose of the
> pesticide.
In this link to Cresswell's research
http://biosciences.exeter.ac.uk/staff/index.php?web_id=james_cresswell&tab=pubs
an abstract to this paper can be viewed:-
Cresswell, J.E. (2011). A meta-analysis of experiments testing the effects
of a neonicotinoid insecticide (imidacloprid) on honey bees. Ecotoxicology,
20(1), 149-157. in which he states;-
" Many studies have tested the effects on honey bees of imidacloprid, a
neonicotinoid, but a clear picture of the risk it poses to bees has not
previously emerged, because investigations are methodologically varied and
inconsistent in outcome. In a meta-analysis of fourteen published studies of
the effects of imidacloprid on honey bees under laboratory and semi-field
conditions that comprised measurements on 7073 adult individuals and 36
colonies, fitted dose-response relationships estimate that trace dietary
imidacloprid at field-realistic levels in nectar will have no lethal
effects, but will reduce expected performance in honey bees by between 6 and
20%. Statistical power analysis showed that published field trials that have
reported no effects on honey bees from neonicotinoids were incapable of
detecting these predicted sublethal effects with conventionally accepted
levels of certainty."
That to me does not accord with the view you have ascribed to him.
.Like all good controversies, the views of the experts conflict, as it seems
they do here. For me it is the mounting weight of opposing evidence, which
has tipped the balance against neonicoinoids, and implicated them as a
synergist amplifying fungal infections to catastrophic proportions in a
number of species including bees. This is an extremely important issue with
ramifications way beyond beekeeping, and heavens knows thats serious enough
not to be sniffed at!
Dr Rosemary Mason has pretty good credentials I would venture to say, and
her hypothesis on this subject encapsulates the opposing views. It is worthy
of some serious consideration. View it here:-
http://www.bouldercountybeekeepers.org/wp-content/uploads/2011/04/Widespread-Immune-Deficiency-Disease-in-Wildlife.pdf
Another article, similar vein, different source
http://e360.yale.edu/content/feature.msp?id=2228
Peter, you and I are not going to resolve this debate when the scientific
evaluations are still progressing. For many beekeepers, like it was for me
until very recently, the "jury is still out". But enough evidence has now
accumulated to convince me, that environmental exposure to agrichems
compromises the bee immune system, effectively augmenting the impacts of
other health problems, such as Nosema infection, to serious levels that can
be causal in hive decline and demise.
PeterD
Western Australia
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