Are agricultural chemicals responsible for Colony Collapse Disorder?
31 August 2010
In summary, the evidence to date does not support this conclusion.
Colony Collapse Disorder (CCD) is a phenomenon noticed particularly in the United States and Europe whereby bees suddenly disappear from their hives. One theory is that agricultural chemicals, particularly a new generation of pesticides called neonicotinoids, may play a role. Research, however, supports the view that CCD may be the culmination of a wide variety of factors and stresses that include parasites, viruses, climate change, nutrition and bee health, lack of genetic diversity and migratory bee keeping.
More information
Colony Collapse Disorder (CCD), a phenomenon in which bees suddenly disappear from hives, has puzzled and concerned beekeepers and scientists around the world. The cause or causes of the syndrome are not yet fully understood. Many authorities attribute the problem to bee parasites such as Varroa mites and Nosema apis, and a number of fungal and viral diseases. Other proposed causes include climate change stress, pesticides, bee health and nutrition, lack of genetic diversity and migratory beekeeping.
In relation to pesticides it is sometimes argued that the cause of CCD is the use of a new generation of pesticides, the neonicotinoids. It is proposed that these pesticides weaken bees and make them more susceptible to disease. The potential impact of pesticides on bees is an issue the Australian Pesticides and Veterinary Medicines Authority (APVMA) takes seriously when doing its work. This comes from the APVMA’s legislative responsibility to ensure that pesticides it registers do not have an unintended adverse impact on animals or the environment.
Studies that assess the environmental toxicity of pesticides to bees are a specific core assessment requirement for any pesticide proposed for field use. Data from these and other studies such as environmental chemistry and fate are used to determine if a pesticide can be safely used and, if it can, under what conditions. The Australian government published a report in 2008, following an inquiry into the future of the Australian Honey bee industry, noting the prevalence of CCD in other countries. This report considered a number of impacts on the industry, including pesticides, their assessment and registration and label statements for pesticide products.
The APVMA has registered a number of chemicals in the neonicotinoid family. These are a class of insecticides that are designed to kill insects by acting on the central nervous systems of insects and have a lower toxicity to mammals. They are among the most widely used insecticides worldwide. Of the six types of neonicotinoid registered in Australia, products based on five are used either as broadscale insecticides or seed dressings and thus have the potential for contact with bees. The assessments undertaken as part of the registration process have identified those that present the greatest risk to bees. These products contain specific label instructions that may, for example, require users not to spray plants in flower while bees are foraging. Where necessary such instructions can be extensive and detailed and include instructions relating to managed bee hives. These instructions are legally enforceable under State law.
Is this regulatory setting appropriate? At a broad level it appears to be. Neonicotinoids are widely used in Australia without Australia experiencing CCD. While there is occasional evidence of hives being impacted through mis-use of pesticides there are few, if any, reports of systemic issues in Australia. Should the regulatory setting nonetheless be continually revised? Yes. The APVMA will continue to follow research around the world and consider decisions taken by other regulators, while looking at new information.
Further reading
A good update of the various hypotheses relating to CCD is provided by in the article ‘Silence of the Bees’ in the March/April 2010 edition of Organic Gardener magazine.
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