Allelopathy, the interaction between plants mediated by chemicals, is drawing growing interest the last few years, especially in agriculture. This phenomenon Could be helpful to optimise weed management in cultivated fields, for instance through allelopathic cultivars breeding, laying of allelopathic ground covers or insertion of allelopathic crops in the rotation scheme. This approach is welcome, particularly with present need of alternatives to chemical weed control. Nevertheless, allelopathy still remains controversial, mainly because it is often difficult to unambiguously distinguish it experimentally from competition effects. This paper presents a synthesis of our results with Artemisia annua, producing artemisinin, a molecule with very potent phytotoxic propel-ties. The mose of action of artemisinin could be demonstrated under lab, greenhouse and field conditions, whereby confirming the reality of allelopathic phenomenon. Preliminary results are also presented concerning the putative role played by this molecule in natural conditions. Lastly, ongoing works using others species, aimed at providing a practical use of allelopathy for weed management of cultivated fields, is briefly described.
