Thesis Abstract

The aetiology of the fungal rot of cucumber fruit (Cucumis sativus L.) in Enugu State was investigated. Five fungal pathogens were isolated from diseased cucumber fruits. They were identified as Fusarium oxysporum Schlecht, Aspergillus niger Van Tiegh, Rhizopus stolonifer Ehrenb. ex.Fr, Geotrichum candidum Link and Mucor micheli ex Staint – Amans. The pathogenicity tests proved them as the causal agents of the rot. The effects of ethanolic extracts of Chromolaena odorata and Moringa oleifera and benlate solution on the isolates wegre also determined. The ethanolic extracts of the test plants inhibited mycelial growth of the pathogens in vitro as well as in vivo. The inhibitory effects of the extracts increased with increase in concentration. All concentrations of 20 mg/ml to 100 mg/ml reduced the mycelial growth of the pathogens to some significant (P > 0.05) level. Benlate solution also reduced the mycelial growth of the pathogens. Phytochemical analysis of C. odorata revealed the presence of tannins, saponins, phenols, flavonoids, terpenoids, glycosides and alkaloids while M. oleifera contained all the phytochemicals except alkaloids. The presence of these active ingredients in the extracts may have contributed to their inhibitory properties. These findings suggest that plant extracts could serve as potential sources of bio-fungicides.

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