Assessing in-field pesticide effects under European Regulation and its implications for biodiversity: a workshop report.

Abstract

Background Biodiversity loss is particularly pronounced in agroecosystems. Agricultural felds cover about one-third  of the European Union and are crucial habitats for many species. At the same time, agricultural felds receive the highest pesticide input in European landscapes. Non-target species, including plants and arthropods, closely related to targeted pests, are directly afected by pesticides. Direct efects on these lower trophic levels cascade through the food web, resulting in indirect efects via the loss of food and habitat for subsequent trophic levels. The overarching goals of the European pesticide legislation require governments to sufciently consider direct and indirect efects on plants and arthropods when authorising pesticides. This publication provides an overview of a workshop’s fndings in 2023 on whether the current pesticide risk assessment adequately addresses these requirements. Results Efects due to in-feld exposure to pesticides are currently not assessed for plants and inadequately assessed for arthropods, resulting in an impairment of the food web support and biodiversity. Defciencies lie within the risk assessment, as defned in the terrestrial guidance document from 2002. To overcome this problem, we introduce a two-step assessment method feasible for risk assessors, that is to determine (i) whether a pesticide product might have severe impacts on plants or arthropods and (ii) whether these efects extend to a broad taxonomic spectrum. When each step is fulflled, it can be concluded that the in-feld exposure of the pesticide use under assessment could lead to unacceptable direct efects on non-target species in-feld and thus subsequent indirect efects on the food web. While our primary focus is to improve risk assessment methodologies, it is crucial to note that risk mitigation measures, such as conservation headlands, exist in cases where risks from in-feld exposure have been identifed. Conclusions We advocate that direct and indirect efects caused by in-feld exposure to pesticides need to be  adequately included in the risk assessment and risk management as soon as possible. To achieve this, we provide recommendations for the authorities including an evaluation method. Implementing this method would address a major defciency in the current in-feld pesticide risk assessment and ensure better protection of biodiversity.