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I wrote about the effects of neonicotinoid pesticides on honey bees in my article on beekeeping in 2009, see 7. Articles (f) Beekeeping.     Now in 2013 neonicotinoid pesticides are in the news and an EU ban on the 3 most toxic will come into force in December, and will last for 2 years.  This is a start.  Neonicotinoids should never have been approved for use.  Regulation (EC) No.1107/2009 Annexe II Criteria for approval p.43 states that “A plant protection product should not be persistent in the environment”.  The persitance criterion is fulfilled where the half-life in soil is less than 120 days.  Neonicotinoids are very persistent, clothianidin (produced by Bayer in 2003, when their patent protection for imidacloprid expired) has a half-life of over 500 days (in some cases persisting for over 3 years):  it is also toxic to earthworms, ants and collembola (springtails), and can build up in the soil year on year affecting (and expressed in) any following crop or wildflower.  They are soluble in water which means that water sources can be contaminated by field run-offs or overspray, potentially devastating aquatic life.  Many different products are produced including seed dressings, foliar sprays, soil drenches, turf applications, home and garden uses, and veterinary products (i.e.  pet’s flea treatment).

Bayer reportedly made US $830 million for sales of imidacloprid and US$267 million for clothianidin in 2010.  In the UK cropland treated with neonicotinoids went from 0.65% in 1994 to 30% in 2010    (3 million acres).

It is argued that there is no proof that bee colonies have been badly affected by neonicotinoids:  this is not true.  North Dakota beekeepers took Bayer to court in 1995 when rapeseed crops were sprayed with imidacloprid and they lost their colonies of bees.  The US has colony collapse disorder (CCD) and a study funded by Harvard Centre for the Environment in 2010 found that when  16 colonies of bees were exposed to low levels of imidacloprid, 15 died out within 23 weeks with identical characteristics to CCD*.   France lost one-third of its commercial honeybees in 1999 following widespread use of imidacloprid as a seed dressing for sunflowers.  In Germany 8 different seed treatments containing neonicotinoids were banned for use on sweet corn following honey bee deaths (11,000 colonies).  Similar die-offs have been reported in Italy, Spain, Switzerland, the Netherlands, Austria, Poland, Hungary, Slovenia, Greece, Belgium, Argentina, Australia, Canada, Japan, China and India.  Japanese ecologists are pressing for a ban.

Many independent studies have found that neonicotinoids affect the nervous system of bees, disrupting foraging, orientation and causing premature death.  Guttation drops (like sweat on the leaves) on treated sweet corn plants will kill thirsty bees within minutes.  No-one has been able to test the effects on developing bees fed contaminated pollen but it is thought that the bees immune systems are compromised, causing increased susceptibility to diseases – and increased levels of the gut pathogen nosema are seen.

In Italy neonicotinoid maize seed treatment was banned in 2008, since then bee populations have been recovering.   The monitoring network APENET reported bee deaths in maize growing areas were reduced to zero during the growing period and winter losses declined from 37.5% to 15% in 2010-11.  APENET has also found that farmers’ untreated maize crops did not suffer reduced yield and productivity was high.  They concluded that banning neonicotinoids on maize greatly reduced bee mortality and by rotating crops pests were kept under control and yields maintained.

Although a 2-year ban is due from this December we should not become complacent.  Britain did not vote for this ban, we abstained.  Two years is not enough given the long lasting contamination of the soil.  Unfortunately politicians seem to be influenced by corporate interests rather than the public or the environment.  The public can make a difference checking ingredients and refusing to buy products containing neonicotinoids (i.e. in garden pesticides and spot-on flea treatments).  There is evidence of adverse health effects on mammals.  Gestational exposure in rats to a single dose of imidacloprid “produced significant neurobehavioral deficits and pathological alterations in their offspring”.    Treated maize is fed to cows and they provide us with milk and meat.

The plight of honeybees has caught the public imagination partly because they are such good pollinators of our food crops.  All other pollinating insects are suffering too and so are birds, bats and amphibians.  You might want to watch an American video “Vanishing of the Bees” online at

*In Situ Replication of Honey Bee Colony Collapse Disorder, by C. Lu, K. Warchol and R. Callahan, Bulletin of Insectology, June 2012.

For the names of all the different neonicotinoid pesticides see Wikipedia online.

Sally Viney


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