Microbial metabolites as eco-friendly agrochemicals for the next millennium

As a result of the increasing environmental and health-related problems caused by the synthetic agrochemicals currently used, suitable and non-hazardous innovative alternatives are being sought. Antagonism and allelopathy, both in nature and in agro-ecosystems, have attracted these researchers' attention, with the main goal of using these phenomena in the biological control of weeds. This article presents a review on the use and efficacy of microbial secondary metabolites which have potential as natural herbicides, either directly or as templates for bio-rational eco-friendly agrochemicals (allelochemicals). Their merits as alternatives to synthetic chemicals and biological control agents have been highlighted for an holistic approach in integrated pest/weed management.