Data, Data Everywhere But We Don't Know What to Think? Neonicotinoid Insecticides and Pollinators

• Published in: Outlooks on pest management Vol. 24; no. 4; pp. 151 - 155
• Main Author: Walters, Keith
• Format: Journal Article
• Language: English
• Published: Saffron Walden Research Information 01.08.2013; Research Information Ltd
• Subjects: Exposure; IPM; Neonicotinoid Insecticides; Policy; Pollinators; Risk Assessment; Sub-Lethal Effects
• ISSN: 1743-1026; 1743-1034
• DOI: 10.1564/v24_aug_02

Pesticides have long been the subject of public and scientific debate. Opinions range from a belief that the potential environmental damage that might result from their use warrants abandonment of these central crop production tools through to endorsement of their continued use under the current registration procedures (which are supported by strict and robust risk assessment). Since their introduction, neonicotinoid insecticides have been subject to the same registration procedures as other groups of pesticides but not withstanding this, during the last ten years they have become a particular focus, with the debate becoming increasingly polarised. At first sight a puzzling aspect of the discussion surrounding the neonicotinoids centres on the recognition that the results of individual studies have frequently been used to support very different and apparently contradictory viewpoints, leading to a barrage of claim and counter-claim in the media. Against this background legislators and politicians throughout Europe have been faced with the need to balance the available evidence to establish whether registration of some or all of this class of insecticides is to continue. How this situation has arisen, and what new information is needed to reach a consensus, have become central questions. The current debate surrounding the effect of neonicotinoid insecticides on pollinators and the consequential moratorium on their use under defined circumstances appears to have been based, at times, on narrowly focused, incomplete and in some cases unrepresentative datasets. It is, however, an important debate and it is vital that we arrive at a scientifically based consensus on the actual impact of this class of pesticides so that realistic conclusions can be drawn on their future use. If such a consensus is to be achieved it is essential that further research is urgently undertaken to fill the current gaps in our knowledge and provide robust datasets upon which informed decision making can be based. It is also important to recognise that concentration on possible effects on pollinators has resulted in less prominence being given to the wider consequences of loss of these pesticides. For example, the proposed ban will increase usage of (and hence selection pressure on) other active ingredients thus increasing the risk of resistance arising and leaving us with fewer options for managing its spread, a risk that is compounded by alternative pest management approaches often not currently being available. Integrated pest management (IPM) and biological control have been promoted as important components of future sustainable crop production. However, much research is required before their potential can be evaluated and fully implemented, particularly in field crops. Some neonicotinoids are also important components of some current IPM protocols (being used in conjunction with natural or introduced predators) and their loss would delay introduction of new systems that will reduce reliance on pesticides. Thus, decisions on the future of these insecticides should not only be based on substantial and reliable scientific evidence on their impact on pollinators, but balanced where necessary with the results of urgent research into alternatives to their use. In summary, to provide legislators and politicians with a reliable basis for decision making: Future experimental design needs to take account of the real risks posed by each exposure route for each active substance, under current registration restrictions. It will need to reflect realistic exposure scenarios, profiles and rates in laboratory, semi-field and field experiments to support the establishment of robust conclusions on the likely sub-lethal effects in the field. An understanding of the importance of insect metabolism of active substances in ameliorating sub-lethal responses should also be reflected in experimental design and data interpretation, and appropriate insecticide residue data should be routinely collected as part of field experiments. It is also important that we investigate and attain an improved understanding of the biological relevance (at both the individual and colony level) of the behavioural and physiological responses used in assessments of sub-lethal effects of these insecticides. Research should be extended to encompass the full range of pollinator groups and insecticides, as the current extrapolation of results gained primarily from work investigating imidacloprid and Apis is inadequate. In addition it should also not concentrate solely on biological responses of the insects, but incorporate technological developments to limit exposures, such as the recent work to reduce dispersal of dusts at sowing. Policy makers and legislators also have a role in establishing a solution to the current situation; for example to enhance confidence (in some quarters) in the risk assessment procedure, re-assessment and, if justified, amendment of the methods by which PECs are calculated for seed treatments would be advantageous. Although there are many research gaps and problems with interpreting existing published work, there is an opportunity to use the period of the moratorium to generate the data needed to establish a basis for balanced decisions on the future of this group of insecticides. Similar issues will inevitably arise in the future for other pesticide groups, so the work of the next two years may set an important precedent; thus it is vital that the science is robust.