Evaluation of two indicators according to the objectives of the Sustainable Use of pesticides Directive (SUD). A French case study

The European agricultural protests of 2023/2024 have prompted a reassessment of public policies at the EU level with the SUR put on a stand still. In France, in early 2024, the government replaced the historical monitoring indicator "NoDU'' with the European Harmonized Risk Indicator HRI1 to monitor the progress in the use of Plant Protection Products (PPP) in its National Action Plan (NAP). This study aimed to assess the relevance of these two indicators regarding the objectives outlined in the Sustainable Use of pesticides Directive (“SUD”) that defines the framework within which they operate. To this effect, we analyzed the PPPs they consider, the official calculation formulas, but also their past evolution and possible future evolutions through putative scenarios of changes in PPP use and regulation: ban or not; substitution or not; for the top 5 synthetic insecticides; all synthetic insecticides; glyphosate; mancozeb; and the top five active ingredients from HRI1 risk group 3 (candidates for substitution). French PPP sales data from 2011 to 2021 were used for past evolutions and we used the last available figures in France, 2021, for simulations.Designed to monitor the use of PPPs by farmers, the NoDU mostly monitors achievement with regards to one aim of the SUD: to "reduce dependency on the use of pesticides" and promote "the use of Integrated Pest Management". Its value does not change with the mere substitution of a product by another, even if the second is deemed less toxic. This limits its ability to assess the "risks and impacts of pesticide use on human health and the environment", the first aim of the directive. The HRI1 indicator is not supposed to strictly quantify the use of PPP and was found to inadequately reflect significant changes in PPP use, but also in the induced risk: 1) changes of use without a ban on a substance are limited and as such, past correlation of HRI1 with the QAI of the fourth group (banned PPPs) is very high (0.90); 2) the impact of variations of low-dose active ingredients is minimal, independently of their toxicity/ecotoxicity, even in the case of a ban. Thus, the putative withdrawal of all insecticides sold, even without substitution by other PPPs, would reduce HRI1 by only 4 in percentage points (from 67.1 % to 63.1 %), while NoDU would drop by 16 percentage points (from 94.5% to 78.5%), thus better reflecting both the paradigm shift in PPP use for farmers and the large diminution of the risk induced for the environment. On the opposite end, banning only glyphosate, a high dose active ingredient, even with full substitution with another herbicide, would bring the HRI1 down to 43.8% of its value in 2011-2013 and sells of glyphosate in 2021 would represent 47.8% of the HRI1 before the ban, when it is only 4.3% of the use of PPPs as measured by the NoDU. Finally, 2022 ban of mancozeb, even if fully substituted by other PPPs, might be enough to bring the HRI1 very near to the 50% target of the Ecophyto plan (56.9%), while the NoDU would remain at 94.5% of its average value in 2011-2013.Our results strongly suggest that HRI1 fails to adequately monitor the objectives of the SUD. We accordingly recommend that the European Commission reconsider the design of Harmonized Risk Indicators. NAP monitoring indicators at national and European level should encompass three primary features. First, the indicators should be founded on robust scientific and technical evidence. Second, they should consider toxicity and ecotoxicity profiles of PPPs. Last, they should be computable for each member state and allow comparisons in absolute values between member states to account for “the risk or use reduction" targets already achieved prior to the application of this Directive.