Neonicotinoid Pesticides and Bees - The Food and Environment ...
Neonicotinoid Pesticides and Bees - The Food and Environment ...
Neonicotinoid Pesticides and Bees - The Food and Environment ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
2.5 Exposure of bees to pesticides<br />
See EFSA 2012 http://www.efsa.europa.eu/en/supporting/pub/340e.htm.<br />
Conclusions<br />
<strong>Bees</strong> are exposed to pesticides via a number of routes <strong>and</strong> the relative importance of each<br />
depends on the life stage of the insect <strong>and</strong> the mode of application of the pesticide. Adults<br />
may be exposed directly to pesticides through direct overspray or flying through spray drift,<br />
by consumption of pollen <strong>and</strong> nectar (which may contain directly over-sprayed or systemic<br />
residues), by contact with treated surfaces (such as resting on recently treated leaves or<br />
flowers), by contact with dusts generated during drilling of treated seeds, or by exposure to<br />
guttation fluid potentially as a source of water or as dried residues on the surface of leaves.<br />
<strong>The</strong> exposure of larvae is primarily via processed pollen <strong>and</strong> nectar in brood food. Data<br />
available in the literature includes residues in pollen, wax <strong>and</strong> nectar within colonies, pollen<br />
<strong>and</strong> nectar residues from plants, in pollen loads on bees returning to the hives <strong>and</strong> in adult<br />
workers. Such data also includes the residues of veterinary medicines detected <strong>and</strong> the<br />
distribution of chemicals around the hive.<br />
<strong>The</strong> routes of exposure of bees to pesticides has been assessed <strong>and</strong> recently reviewed in an<br />
EFSA Scientific Opinion particularly in relation to quantifying uptake <strong>and</strong> extended to include<br />
other non-Apis species where data were available. <strong>The</strong> exposure of bumble bees to<br />
pesticides has also been reviewed <strong>and</strong> showed there are key times in the year when<br />
exposure of queens may be particularly important in determining the fate of a colony.<br />
A review of residues in bees after pesticide applications in the EFSA review (2012) provides<br />
evidence of the exposure of bees to applications aggregated through all routes of exposure,<br />
i.e. through direct overspray, foraging on treated crops <strong>and</strong> consumption of treated food <strong>and</strong><br />
water as samples were collected over time after exposure. This showed peak residues in the<br />
first sample after application with declines for spray applications over the following week. No<br />
data from systemic seed or soil application field studies were available but residues of<br />
imidacloprid <strong>and</strong> its metabolite 6-chloronitoctinic acid <strong>and</strong> fipronil <strong>and</strong> its metabolites were<br />
detected at low levels in monitoring studies<br />
Studies on residues deposited as dust containing neonicotinoids are summarised obviously<br />
this does not take into account recent EU requirements to limit dust emissions through the<br />
use of professionally treated seeds <strong>and</strong> deflectors. Drift during agricultural treatment<br />
determines the deposition of pesticides within a small distance from the field edge. What is<br />
less obvious is how to calculate the drift onto flowering weeds in the field margin as dust drift<br />
is unlikely to behave in the same way as spray drift due to the wide variations in particle size.<br />
Unfortunately the deposition data generated to date for grasses <strong>and</strong> flowering weeds in<br />
flower margins have limitations in terms of the reporting of sowing rates <strong>and</strong> seed treatment<br />
rates.<br />
Contact of bees with treated surfaces may occur through resting on treated leaves or during<br />
foraging on treated flowers. <strong>The</strong> major issue is that bees do not come into contact with the<br />
treated plant over the entire surface of their body but primarily through their feet; however<br />
<strong>Neonicotinoid</strong> pesticides <strong>and</strong> bees Page 42 of 133<br />
Report to Syngenta Ltd