Mangroves are the only forests located at the sea-land interface in the tropical and subtropical regions of the world. Mangrove species, which develop in intertidal zones where wave energy is lower allowing thin sediments deposition suitable for mangroves settlement and development. These forests are key elements of tropical coastal ecosystems, providing numerous ecosystemic services such as raw material and food production, habitats, limitation of costal erosion and salt intrusion. Another service is the production of secondary metabolites by mangrove species and their potential use in medicine and/or agriculture. Indeed, contrary to the synthetic pesticides which are associated to negative environmental impacts (soil persistence, non-targeted toxicity, carcinogenic and mutagenic activities, etc.), use of natural pesticides and herbicides is generally considered safer for the environment and the human health, particularly due to their implicit biodegradability, their highly selective actions, etc.

We explored the allelopathic potential of 8 mangrove species (Avicennia marina, Kandelia obovata, Bruguiera gymnorrhiza, Sonneratia apetala, Sonneratia caseolaris, Aegiceras corniculatum, Lumnitzera racemosa and Rhizophora stylosa) on the development of plants from an adjacent agrosystem (target species Oryza sativa and Echinochloa crus-galli). The results of our experiment reveal that the leaves aqueous extracts mangrove trees might affect in several ways the germination and the growth of the target species linked to their chemical signature. These fallouts seem especially important as Vietnam is currently facing serious challenges concerning both the quantity and the toxicity of the pesticides used in agriculture.