Herbicides made from natural molecules may be a good environmentally friendly alternative to synthetic chemical herbicides for weed control. As a result, this investigation was carried out to ascertain the phytotoxicity of Parthenium hysterophorus L. as well as to identify its phenolic components. Germination of seeds and devel-opment of seedlings of Vigna subterranea (L.) Verdc, Raphanus sativus (L.) Domin, Cucurbita maxima Duchesne., Cucumis sativus L., Solanum lycopersicum L., Capsicum

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... cens L., Zea mays L., Abelmoschus esculentus (L.) Moench, Daucus carota L., Digitaria sanguinalis (L.) Scop and Eleusine indica (L.) Gaertn were investigated using P. hyster-ophorus leaf, stem, and flower methanol extracts. Six concentrations (25, 50, 75, 100, and 150 g L-1) were com-parison to the control (distilled water). The concentration of extracts increased, the rate of the seed sprouting and seedling growth decreased. EC50 values showed that the extraction of leaf of P. hysterophorus (811) was phytotoxic in comparison to the stem (1554) and flower (1109) extract. According to PCA analysis, Raphanus sativus, Solanum lycopersicum, Capsicum frutescens, Abelmoschus esculentus, Daucus carota, Digitaria sanguinalis, and Eleusine indica were all very susceptible to allelochemicals. LC-MS analysis revealed that the P. hysterophorus leaf extract contained 7 phenolic compounds that were responsible for inhibition. These studies also revealed that the leaf of P. hysterophorus is a major source of phytotoxicity, which could be valuable in the future for developing a natural herbicide.