These products are systemic. They are absorbed and carried into all parts of the plant, including flowers, pollen and nectar. Here they are available to be collected by bees and returned to hives for storage and feeding to other bees and progeny. Foragers are also exposed through direct contact with sprays, dust and residues on foliage. It doesn’t end there, as if that wasn’t enough. Neonicotinoids are very persistent in the environment, with a long half-life in soil, as many as years in heavy soils. They can be leached out by heavy rains into the ground water and thence into creeks, dams and river systems. Once applied, residues can persist and build up in soils so that they last from 1 year to the next and are available to be picked up by successive crops. A recently published book by Dr Henk Tennekes, a toxicologist in The Netherlands, paints a bleak picture of the current parlous state of European wildlife that can be directly related to neonicotinoid use (www.disasterinthemaking.com). Using imidacloprid as an example, he shows that it has leached into waterways over an extensive area with devastating results on aquatic and terrestrial invertebrates and therefore the wildlife dependent on them, particularly birds. Estimates of amounts applied worldwide are difficult to find, but Bayer CropScience reportedly earned a tidy US$830 million for global sales of imidacloprid and US$267 million dollars for clothianidin in 2010 alone.
Unlike some other countries, pesticide usage data is not collected in Australia. The APVMA authority extends only to the point of retail sale, though the organisation collects a levy based on dollar value of product sold (www.apvma.gov.au/about/reporting/product_sales.php). The scale of the potential problem in Australia is basically unknown unless the pesticide companies can be persuaded to release their sales volume data for individual pesticides, an unlikely prospect without a statutory requirement. The sales data for agricultural chemical products make interesting reading. Sales of insecticides and fungicides alone from 2004-2010 amounted to AU$500-$625 million per annum, with household insecticides making up more than a third of this total. Hopefully, the latter is a reflection of profit margin rather than volume applied, but it is still concerning.
In Part II the authors explore the evidence for neonicotinoid impacts on honey bees, the role of governments in regulating pesticides, and the changes required to adequately evaluate their environmental safety.
About the authors
Stephen Goodwin and Marilyn Steiner are IPM consultants trading as Biocontrol Solutions at Mangrove Mountain. Email: sgoodwin.msteiner@gmail.com
Reference
Funase, S. 2008. Neonicotinoids, Devilish Novel Pesticides. Silent Summer Without Bees. Sangokan, Tokyo. 235pp.
