Camilla Drocco

Abstract: Within the ARISTO project, this thesis addresses the need to advance the Environmental Risk Assessment (ERA) of pesticides for soil microbes. Given the magnitude of pesticide applications annually and the possible accumulation of active ingredients and their main residues in soil, there is an urgent need to develop an accurate and effective risk assessment strategy. Particular attention is directed towards ammonia oxidizers, crucial contributors to the soil nitrogen cycling. While soil microbial responses to pesticides are relatively well studied, there is a significant knowledge gap regarding the effects on free-living nematodes, organisms closely interacting with the microbial community. This thesis aims also to explore this gap by investigating the responses of both soil microbes and free-living nematodes communities to pesticide mixtures, through a lab-tofield experimental approach. Molecular techniques such as qPCR and next generation sequencing were employed to study changes in microbial community due to pesticide mixture application, while impacts on free-living nematodes were recorded with the traditional taxonomical identification. Our findings suggest that pesticide mixtures do not have a stronger impact on the microbial and nematode communities than that produced by each of the pesticide studied seperately. Overall, molecular techniques targeting microbes and taxonomical identification of nematode provide comprehensive information on the impact of pesticide mixture on the key players of the soil food web, that could be of interest to be implemented in a further revision of the current pesticides EU regulation.

Date and time: 14 octobre 2024 at 9h00
Location: Amphithéâtre Ampère - Université de Bourgogne - UFR SVTE - Batiment Gabriel - 6, boulevard Gabriel - 21000 Dijon.

Jury:
M. Aymé SPOR - Directeur de thèse / Directrice de thèse : ayme.spor@inra.fr
Mme Lise BARTHELMEBS - Rapporteur / Rapporteure : barthelm@univ-perp.fr
M. Stéphane PESCE - Rapporteur / Rapporteure : stephane.pesce@inrae.fr
Mme Anja COORS - Co-encadrant de thèse / Co-encadrante de thèse : a.coors@ect.de
Mme Cécile VILLENAVE - Examinateur / Examinatrice : cecile.villenave@elisol-environnement.fr
M. Stéphane VUILLEUMIER - Examinateur / Examinatrice : vuilleumier@unistra.fr