Efficacy Assessment in Agriculture

Crops & Chemicals Europe sponsored by: SCC

For those who could not attend Dr Norbert Weissmann’s presentation on ‘Efficacy Assessment in Agriculture’ at Crops and Chemicals Europe 2017, we are pleased to provide the key points of his talk hereafter.

A short introduction in the history of regulatory efficacy was given. Once, guidance on efficacy was provided primarily by EPPO and on national level. As efficacy played no role in the review of active substances according to directive 91/414, there was no legal pressure for harmonization in the entire efficacy. This changed on 14 June 2011 as after this date, following regulation 1107/2009, all product applications in EU member states had to be submitted on zonal level. In this context a harmonized dual structure of Biological Assessment Dossier (BAD) and the dRR section 3 (formerly 7) was developed in two EPPO workshops at Berlin and Sofia in 2011 and 2013.

In the course of this development several challenges and regulatory developments in efficacy appeared, such as the need for preparation of comparative assessments, which is obligatory for products containing active substances listed as candidate for substitution. A tiered assessment on national level has to be performed, indicating the products agricultural indispensability, e.g. because it is needed to sufficiently defend diseases and pests in minor crops.

Furthermore it became more and more important to provide comprising dose justification information. This is due to the fact that during the course of the renewal of approval of active substances a need for reduction of the current dose rate may be evoked by recalculation of risk assessments, e.g. from the ecotoxicology section. Dose justification trials containing a reduced dose rate with lower, but still sufficient efficacy, may preserve the registration holder conducting a new trial program.

One of the most important factors regarding efficacy in the framework of product renewals according to Article 43 of 1107/2009 is an update of the data point resistance risk, based on recent data. Fighting and delaying the process of resistance development is of key importance for the whole plant protection industry, and inclusion of the product in integrated pest management strategies has to be strongly considered.

For future efficacy trials new requirements have to be taken into account. For example the assessment of parameters needed for calculating the leaf-wall-area (LWA) as dose expression for 3D-crops, e.g. the distance between and within the rows, the sprayed height, the canopy density, shape and growing system of high growing crops. This was controversially discussed in the EPPO workshop conducted in Vienna in 2016.

Another example is the new EPPO standard PP1/291 on ‘Evaluation of the influence of tank mixture adjuvants on the efficacy of plant protection products’, providing advice for better design of trials and a guidance for efficacy testing with mandatory (e.g. twin packs) or voluntary mixtures of product and adjuvant.

For the efficacy testing of biopesticides and biostimulants specific EPPO standards have to be taken into account, besides the general standards. However, the data requirements (e.g. number of trials, bridging options) for ‘low risk substances’ are reduced, and respective further guidance will be provided in an EPPO standard expected to be published in September 2017.

In case of any particular questions which could not be addressed adequately in this summary, please feel free to contact Dr Weissmann directly by phone (+49 (0)671-29846-151) or email (norbert.weissmann@scc-gmbh.de).

Dr Norbert Weissmann 

Senior Manager Regulatory Affairs Agrochemicals and Biopesticides - Head of Efficacy group at SCC

Tel: +49 (0)671-29846-151

Email: norbert.weissmann@scc-gmbh.de

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