Abstract

 The present study was undertaken to assess the in vitro antifungal activity of petroleum ether, chlo-roform, methanol and aqueous extracts of Datura metel L. leaves and flowers, against two Trichoderma species (Trichoderma harzianum and Trichoderma viride) and three formae speciales of Fusarium oxysporum, that is, Fusarium oxysporum f. sp. melonis, Fusarium oxysporum f. sp. lycopersici and Fusarium oxysporum f. sp. tuberosi. Radial growth of the pathogen on PDA plates was recorded after 3 to 7 days of incubation at 25°C. Results revealed an important antifungal activity of D. metel leaf and flower aqueous extracts at all concentrations tested (1, 2, 3 and 4%) against pathogenic fungus.How-ever, the extent of response to extracts was species specific. In fact, the highest inhibition (69%) of T. viride mycelial growth was observed with flower aqueous extracts. Indeed, F. oxysporum f. sp. melonis was found to be more susceptible than the other fungal species to organic extract; radial growth inhibition varied from 24 to 76% and from 31 to 76% in the presence of leaf and flower organic extracts, respectively. In addition, the radial growth of F. oxysporum f. sp. Lycopersici was reduced by all organic extracts. The fungicidal activity of leaf extracts was more effective against F. oxysporum f. sp. tuberosias compared to flower extracts. Both Trichoderma species were less sensitive to D. metel organic extracts than Fusarium species. Our findings showed that D. metel extracts can be used as potential source of fungicides to control the phytopathogenic fungi tested.

Key words: Antifungal activity, aqueous and organic extracts, Datura metel, Fusarium, Trichoderma, radial growth.