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Bees and chemicals

Bees and Chemicals

European Parliament, Directorate-General for Internal Policies. Existing Scientific Evidence of the Effects of Neo-Nicotinoid Pesticides on Bees,

December 2012

Neo-nicotinoids work by blocking specific neural pathways in insects’ central nervous systems. In bees, they impair communication, homing and foraging abilities, flight activity, bees’ sense of smell, learning and immune systems, thereby seriously affecting their ability to survive. Honeybees’ genetic system makes them particularly vulnerable to neo-nicotinoids.

Bees employ two strategies to protect themselves:

  • When foraging in a new area, scout bees are sent to taste the new nectar and pollens. If the scouts are adversely affected, they will be expelled from the hive and the colony will avoid the area.

  • When foraging begins, the house and guard bees in the hive clean the foragers every time they return.

Honey bees live and work as a colony, not as individuals, however the cumulative impact of small doses of neo-nicotinoids over time affects the individual bee’s ability to work and communicate effectively as part of the colony. Neo-nicotinoids cause many hundreds of bees in each colony to behave sub-optimally leading to Colony Collapse Disorder.

Neo-nicotinoid insecticides were first used commercially for Colorado beetles in the United States in 1995. Beetle populations were tested from 1998 to 2010 for imidocloprid and thiamethoxam contamination using standard assays for adults. From 1998 to 2001, imidocloprid resistance was present in a few locations in the eastern United States. By 2003, imidocloprid resistance was common in the northeastern United States and by 2004 imidocloprid resistance in Colorado beetles was detected for the first time in the Midwestern United States. By 2009, 95% of the populations tested from the northeastern and midwestern United States had significant higher resistance for imidocloprid than the susceptible population.

The European Commission introduced a two year ban on the use of neo-nicotinoids from December 2014. There has been much discussion on the use of these chemicals worldwide. In May 2008 at least 300 million bees were killed in the western part of Germany by Bayer’s clothiandin pesticide which was used as a dressing on maize seed. At least 7,000 beekeepers contacted the Landsverband Badischer Imker (Beekeeper’s Union) to report total losses. Greenpeace stepped in and reported that pesticides manufactured by German multinational company Bayer pose the biggest threat to human health and the environment, however, Syngenta (Swiss), Monsanto (United States), BASF (Germany) and Dow Chemical (United States) are on the list of harmful companies.

The Greenpeace report, The Dirty Portfolios of the Pesticides Industry, provides the first ever ranking of the world’s leading agrochemical companies based on the risks of their pesticides on human health and the environment. These listed multinationals account for 75% of the world market and 243 (46%) of the 512 pesticides they sell worldwide are particularly hazardous for humans and nature generally. The EU is at present negotiating new legislation for the authorisation of pesticides.

A Greenpeace chemicals expert explained the ranking list showing how toxic the leading agrochemical companies remain. Politicians must use EU pesticide laws to protect human health and preserve biodiversity. Pesticides cause cancer, alter genes, damage the reproductive, endocrine or nervous system and that harm bees or aquatic life must be withdrawn from sale. The chemical industry actively lobbies for authorisation for these toxins.

At least 46% of multinational companies’ pesticide stocks are particularly dangerous substances. A further 16% of chemicals’ toxic effects are not available in public databases. EU laboratories consistently fail to detect the residues in human food of at least 42% of pesticides in the market. Pesticides are in the environment, in human food, in human’s bodies thereby threatening human health along with many endangered animal and plant species.

Monsanto has the highest proportion (60%) of pesticides particularly toxic to humans and the environment generally. Monsanto is in the middle of the Greenpeace ranking list due to its small market share which includes quantities sold worldwide.

The United States authorities are examining their current difficulties with Colony Collapse Disorder (CCD) and now accept the biggest threats to honeybees are chemicals, varroa and weather, so that all three are causing the CCD problem.

The journal Scientific Reports imparts that as pesticides weaken bees they then succumb to disease. The decline of honeybees was headline news a decade ago in particular with the deaths of entire colonies in the United States, now known as Colony Collapse Disorder (CCD). The United States has fewer managed pollinators than at any time in the past five decades. European countries have witnessed a decline in honeybee numbers with the UK honeybee declined by 50%.

Bees are crucial to pollinating flowers and to producing food. Billions of Euro are invested to solve this drastic decline in bee numbers, so, there have to be controls on harmful pesticides.

EU Press Release Fipronil, Brussels July 2013:

EU member states supported a proposal to restrict the use of Fipronil, an insecticide, which is identified as posing an acute risk to Europe’s honeybee population following a scientific risk assessment carried by the European Food Safety Authority (EFSA) in May 2013 which clearly identified that seeds treated with pesticides containing Fipronil pose an acute risk to Europe’s honeybee population.

The requirement:

Restricts the crops where Fipronil is used as a seed treatment;

Seed treatments with Fipronil may be allowed for seeds sown in greenhouses, brassicas excepted due to their being harvested prior to flowering; the treatment of maize and sunflower seeds is no longer authorised.

European Honeybees are drastically affected by Neo-Nicotinoid Pesticides

The shift from the older pesticides, which react to pests to the current preventative strategy which are systemic pesticides, remaining active in the crop until harvest, then persist in the soil for years to be absorbed by later crops, or wild flowers, and are equally poisonous to bees and wildlife.

The French experience with Bayer’s neo-nicotinoid Imidacloprid:

Imidacloprid, invented in 1985, was granted a licence in 1994, when the bee crisis commenced with 450,000 French bee colonies dying out after feeding on sunflowers treated with Bayer’s Imidacloprid. Bayer denied responsibility. Independent research demonstrated the persistence of Imidacloprid with bees affected by just 3 to 5 parts per billion (ppb).

Further research demonstrated that neo-nicotinoid insecticides caused genetic defects in bees. Imidacloprid adversely affected the lifespan of the honeybees. The transparency of pesticide trials by chemical companies

has been discussed in the United States.

The scientific research on neo-nicotinoids is not conclusive. Field experience consistently fails to match laboratory research. The current ban on neo-nicotinoids cannot prevent the return of older cruder insecticides and should the ban be continued or automatically lifted then how could sub-lethal effects, accumulation, degradation and dispersal be measured?

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