20 different pesticides and 2 metabolites were found.
Further sample analysis has increased these numbers to
75 different chemicals (even including DDT). What such
residues mean is not answered in such surveys.
Surprisingly the pesticide ‘family’ most suspected by
beekeepers, the imidacloprids, is not widely found in the
analysis.
VARROA CONTROL CHEMICALS
Of the three compounds most commonly found in both
pollen and wax samples analyzed, two materials are used
widely by beekeepers for varroa mite control: theMost frequently detected pesticides in brood nest wax of
pyrethroid fluvalinate and the organophosphate (OP)honey bees (Frazier et al)
coumaphos. These two materials were found in 100% of
the brood wax samples. The OP chlorpyrifos, widely useduniversity research centers and scientific agricultural
and known for long residue activity, is the third mostcircles is that several interrelated factors contribute to
common contaminant (see the figure from Frazier et al,CCD. Precisely what is weakening the bees, making them
left). Residues are found in virtually all portions of thesusceptible to a final blow, which appears in the form of
hive, especially in beeswax but less commonly in honey. several pathogens, is yet to be determined. From our
samples of sick and dying bees, we find a higher level of PESTICIDE SCREENING
pathogens in the sick hives, including viruses, Nosema
and mites. In greenhouse tests, the stressed bee adults Based on this recent evidence of high pesticide levels inwax, pollen and brood, a cost-sharing program has
with viruses leave their hive and die ‘outside’ the hive recently been announced which will enable US
itself. But just how all these factors interact is still under beekeepers to have samples from their own
active investigation (see ScienceNews:
http://www.sciencenews.org/view/generic/id/39117/title/
Honeybee_CSI_Why_dead_bodies_can%E2%80%99t_be_
found).
ARE PESTICIDES TO BLAME?
Beekeepers feel pesticides are killing their colonies. We
lack scientific proof that pesticides are solely responsible
for CCD.
The old adage ‘look and you will find’ appears to apply to
pesticides in bee hives. In a continuing study of pesticide
residues, a CCD Task Force/Penn State University study
led by Maryann Frazier finally found a laboratory willing to
analyze pollen and beeswax for residues at ppb (parts per
billion) levels. Such analysis involves precise laboratory
equipment but both pollen and beeswax ‘gum’ up the
sensitive machines and few laboratories will do such
analysis.
They reported the initial results in the July 2008 issue of
American Bee Journal and on the http://MAAREC.psu.edu
CCD website. Of 108 pollen and bee bread samples
analyzed (most from colonies with CCD symptoms but
also control colonies), 46 different pesticides, including
6 metabolic derivatives, were found in this vital bee
resource. Samples analyzed averaged 5 pesticides; one
sample had 17 different pesticides and only 3 had zero
detectable residues. In a total of 88 brood wax samples,
Bee Craft America January 2009 Page 17
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