Antifungal activity of leaf extracts and essential oils of some medicinal plants against Didymella bryoniae

The fungitoxicity of crude extracts and essential oils of Achillea millefol ium, Cymbopogon citratus, Eucalyptus citriodora and Ageratum conyzoides on the fungus Didymella bryoniae was verified in vitro by means of germination of spores and mycelial growth. In addition, some observations were made us ing scanning electron microscopy (SEM) to detect possible alterations on th e hyphae of Didymella bryoniae. The results revealed that crude extracts of E. citriodora and A. conyzoides were more effective in inhibiting the myce lial growth of D. bryoniae whereas in the germination of spores A. conyzoid es and A. millefolium were responsible for most of the inhibition, namely, 52 and 46%, respectively. The essential oils of C. citratus, A. conyzoides and E. citriodora provided 100% inhibition of the mycelial growth and germi nation of spores of D. bryoniae. SEM observations revealed alterations in t he growth pattern of hyphae of D. bryoniae when the essential oil of A. mil lefolium was present.