Normes OEPP EPPO Standards Efficacy evaluation of plant protection products Evaluation biologique des produits phytosanitaires

Resistance is the naturally occurring, inheritable adjustment in the ability of individuals in a population to survive a plant protection product treatment that would normally give effective control. Although resistance can often be demonstrated in the laboratory, this does not necessarily mean that pest control in the field is reduced. ‘Practical resistance’ is the term used for loss of field control due to a shift in sensitivity (EPPO, 1988). Loss of performance of a plant protection product because of the development of practical resistance in the target organism and the subsequent need for additional product use to achieve control can be costly to the grower, the crop protection company and the environment. Furthermore, the loss of efficacy due to resistance may remove the plant protection product from the range of methods available to combat the large potential losses caused by plant pests. Registration authorities and crop protection companies now recognize that the development of resistance can be minimized (i.e. delayed or kept at a low level) by means of suitable management strategies, and that it is in both their interests to protect the efficacy of plant protection products. The registration procedure, before the product is released for full commercial use, is seen to be the point at which appropriate risk management strategies should be agreed and implemented. For example, the harmonized registration procedure of the countries of the European Union (EC, 2009) requires that applicants provide information on the possible occurrence and development of resistance (including information on related active substances, other pests or other crops that could indicate the likelihood of resistance developing). If there is evidence to suggest that difficulties of control could result from the development of resistance, a management strategy should be proposed that would minimize the likelihood of resistance. These requirements do not provide any specific guidance on the scale and scope of evidence that should be submitted, nor is any guidance given on the evaluation of this data or of the proposed management strategy. The aim of this Standard is therefore to indicate to the registration authorities and to applicants for registration what their obligations are with regard to assessing and managing the risk of practical resistance in the target organism(s). These elements are included in the process of resistance risk analysis (i.e. evaluation of the risk followed, if necessary, by the choice of management options). The Standard provides guidance on: • the concepts of resistance; • how resistance risk might be assessed; • how resistance might be managed; • what data should be supplied to support the conclusion of a resistance risk analysis; • other data needed on resistance in the registration dossier; • reaching a registration decision with regard to resistance risk. The Standard covers all types of plant protection products. It does not cover the registration of genetically modified plants that express pesticidal activity, but it does consider their possible influence on the development of resistance in plant pests. Appendix 2 indicates different approaches for the main types of plant protection products.