If you are 'seriously' interested the fifteen year long Scientific debate behind the European ban on neonics, please read the full document at the link below. Those of you who are not interested - just don't bother; it requires some effort.
I have abstracted the crucial section on the TIMELINE of how this poison got onto the market; how and why 1 million French bee colonies died as a result - and why the French government then banned Imidacloprid after considering more than 120 Peer -Reviewed Scientific Papers. The main evidence however, came from the beekeepers
The abstract below shows that Bayer's strategy - in terms of the Four Dog Defense, was as follows:
1994 - Deny that the pesticide presents ANY risk to bees at all - because it is biologically impossible for it ever to appear in the flowers. That got them the license.
1995-97 - Admit that they were wrong - it DOES come out in the flowers, but only in tiny, tiny amounts that could never harm a bee - and the million colonies which died among the sunflowers treated with the poison - COINCIDENCE!
1998-1999 Bayer said its scientists could not find, or could not quantify 'how much' imidacloprid came out in the flowers.
Independent researchers had no problem finding it and quantifying it.
1997-2002 Bayer admits that imidacloprid is present in pollen and nectar at 1.9 ro 3.3 ppb - but claim that no toxic effect was seen until the dose reached 5000 ppb - so it was still safe. Independent research shows bees were intoxicated and died at just 5ppb - one thousand times less than Bayer claimed.
. . . it just goes on and on. See for yourself.
The truth is that we are trying to retrospectively prove something is safe or not safe 20 years after it was first licensed - and ten million dead bee colonies later. You are supposed to verify that pesticides are safe BEFORE they are unleashed on the world.
Bayer claimed that imidacloprid applied on seeds
cannot be present in flowers, because it disappears
before the treated plants flower
The consistent association between
the use of Gaucho® in treating sunflowers and the
appearance of intoxication symptoms in bees during sunflower
foraging, however, led beekeepers to suspect
the presence of the substance in those parts of the
plant utilized by honeybees.
All of Bayer's studies concluded that Gaucho® used
in sunflower seed-dressing is harmless for honeybees
significant lack of quality in Bayer's studies was
repeatedly demonstrated by independent scientists.
Beekeepers and local/departmental state services also
carried out field studies and showed the occurrence of
bee symptoms in areas of extended monocultures seed-dressed
with Gaucho®, and the absence of other
The studies undertaken by Bayer during this period
either could not detect imidacloprid or detected it,
but could not quantify it (GVA, 2006; SCT, 2003).
One exception was a laboratory study that quantified
the substance (imidacloprid) in sunflowers treated with Gaucho® to
be 3.3 ppb in pollen and 1.9 ppb in nectar (Stork,1999)
The first independent
research program (INRA, CNRS and AFSSA, 1998)
identified the presence of imidacloprid in plants
during flowering and abnormal honeybee behavior
at both treated and control sites. This last finding led
the researchers to address the problem of imidaclo-
prid's persistence in soils and its presence in
untreated crops cultivated in soils previously used
for treated crops (Bonmatin et al., 2000).
Bayer received precise results during this period
(3.3 ppb in sunflower pollen and 1.9 ppb in nectar
(Stork, 1999, in SCT, 2003)). Nevertheless, the
company reported “an exposure between 0 and
5 ppb” The value of 5 ppb is the quantification limit declared by Bayer
for the dosage of imidacloprid in Gaucho®-treated
sunflowers and maize. We, however, showed that
Bayer had already obtained lower measurements
(using radioactivity-based methods). In view of the
relevancy of the existing knowledge, this ‘semantic
slip’ blurs the message by strategically selecting
among the measurements available.
Moreover, independent research had already
reported (two years before) available quantification
and detection limits well below those used by Bayer:
quantification limit at 1 ppb (pollen and nectar) and a
detection limit at 0.3 ppb for pollen (Bonmatin,
2001, in SCT, 2003) and 0.8 for nectar (Lagarde,
2000, in SCT, 2003). Imidacloprid was measured in
the pollen of sunflowers and maize in concentrations
between 2 and 4 ppb.
Recently published results of a survey initiated in French apiaries to
monitor the weakness of honeybee colonies showed
that imidacloprid had become a common contaminant
of the environment (the most frequently found
residue was imidacloprid: in 49.4% of the samples)
(Chauzat et al., 2006).
3.3. The lowest effect concentration
In 1997, Bayer declared that the first biological
effects (only appear in bees) at 5000 ppb. Two years later,
however, the LOEC (lowest observed effect concentration)
value identified by a Bayer study was
well below this value: 0.5 to 7 ng/honeybee (20 ppb)
(Kirchner, 1999, in SCT, 2003).
In 2000, sublethal effects were identified at very low doses (0.075–
0.21 ng/honeybee, i.e., 3 ppb in a solution containing imidacloprid)
by scientists working in independent
research (Colin and Bonmatin, 2000, in SCT, 2003).
Beekeepers continued to present the results of
independent research, emphasizing that doses as
low as 3 ppb and 6 ppb affect honeybees (GVA,
Bayer claimed that the lowest effect dose is 20 ppb,
but failed to mention that this result was obtained
during an open-field study. Thus, the company stated
that for the studies “made on complete colonies in the
open field… the first negative effects are not observed
at 20 ppb. The first observed effect of imidacloprid is
a refusal to feed from the contaminated source and
thus the end of foraging”
This claim inadequately reflects the results of
the respective study (Kirchner, 1999, 2000, in SCT,
2003), in which the effects observed in the open field,
and caused by 0.5–1.4 ng/honeybee (20 ppb), were
not the refusal of feeding, but a decrease in the
frequency of wagging dances (which is correlated to
recruitment in the colony for a food source), a change
in dance precision (concerning the direction), and the
occurrence of trembling dances (which is an inhibiting
behavior for foraging recruitment and often
observed in intoxicated bees) (Kirchner, 1999,
2000, in SCT, 2003).
Based on the results produced by independent
research, the beekeepers supplied arguments in
support of their demand to ban the use of Gaucho®.
Three of the available results for the effect dose of
imidacloprid were validated in 2002 by the Commission
for Toxic Products and ranged from 0.15 ng/
honeybee (laboratory) to 7 ng/honeybee (open field).
3.5. Impacts on non-target organisms and on the environment
Bayer judged the risks that imidacloprid forms for the
environment to be either 'non-existent' or ‘acceptable’
Available scientific knowledge, however,
indicated negative effects on other insects (including
pollinators), birds, and aquatic organisms.
Both researchers and beekeepers insist that the honeybee, in
this case, represents a bio-indicator for the state of the
environment. The Minister of Ecology also held
imidacloprid responsible for the bird intoxication
observed in France after 1995 (GVA, 2006). Imidaclo-
prid authorization data in several countries has shown
different toxicity levels for birds, pollinating insects
(particularly honeybees), fish and other aquatic organisms,
and mammals (pesticides authorization registers
for Portugal, Belgium, Spain, Canada, and the United
States, websites visited in January 2006).