An Evaluation Of Fungicidal Capacity Of Ethanol Extract Of Vernonia amygdalina (DELL) On Yam Tuber ( Dioscorea rotundata Poir) Rot

摘要

The fungicidal activities of Vernonia amygdalina extracts were evaluated on the rot causing pathogens of yam tubers in vitro . The ethanol extracts of V. amygdalina were prepared and 1ml of the extract was dispensed into plate and allowed to solidify along with molten PDA. The isolated rot organisms: Botryodiplodia theobromae, Aspergillus niger, Aspergillus flavus and Aspergillus glaucus from rotten yam tubers were inoculated and incubated separately for 5days, inhibition was determined by measuring with metre rule along two perpendicular lines drawn at the bottom of the plate. The results showed that all the concentrations of the extracts had remarkable reduction effects on radial mycelial growth of the isolates. Ethanol extracts of 10% and 20% of V. amygdalina at 10g and 20g/100ml inhibited A. niger and B. theobromae by 92.95 and 97.14% respectively, similarly, ethanol extracts of 30% of V. amygdalina at 20 and 30g/100ml inhibited A. flavus by 100%. Ethanol extracts of 40% of V. amygdalina at 50g/100ml inhibited B. theobromae by 92.38 %, ethanol extracts of 50% of V. amygdalina at 50g/100ml inhibited B. theobromae by 90.48%. The results from this finding herald the appealing fortunes of a potentially viable antifungal agent of plant source.