imson weed (Datura stramonium L.) is an invasive weed plant that produces alkaloids that are particularly toxic to humans (crop contamination) and animals (fodder). The objective of my research project is to find a biocontrol solution based on the use of fungi (even oomycetes) and/or plant extracts to control this plant in agricultural plots. At first, I focus on the research of mycoherbicides. The presence of pathogens or phytotoxic metabolites for jimson weed in a panel of non-infested soils to highly infested soils is tested by applying aqueous extracts or filtrates (0.2µm) of these soil extracts to datura seeds placed on germination paper under controlled temperature and humidity conditions. 80% of the control seeds (supplied with sterile water) germinate on day D+5 while 60% do with the soil extract and 70% with the soil filtrate. This result suggests that microorganisms present in the soil extract, and to a lesser degree phytotoxic molecules present in the filtrate inhibited the development of jimson weed. The fungal diversity of these different soils will be analyzed using high throughput sequencing. This should allow us to look for a link between fungi richness, fungal communities structure, presence of datura and crop management technique. At the same time, one hundred and thirty-one fungal isolates were isolated from jimson weed seedlings exhibiting damping off symptoms, grown in a climatic chamber under controlled temperature and humidity conditions. The pathogenicity of these isolates, among which the most represented genera are Alternaria and Fusarium, is tested using bioassays in climatic chamber. Several stages of datura development will be considered: non-germinated seeds and germinated seeds on germination paper, and seedlings at the two-cotyledon stage in tests in pots containing a compost-perlite mixture to test the pathogenicity of the isolates on the three characteristics of damping off (inhibition of germination, root and crown rotting). I will present you the results of this screening of my 131 isolates during our next doctoral days or during an upcoming internal seminar.