Aqueous and ethanolic extracts of Vernonia amygdalina L. in the control of fungi associated with Arachis hypogeae L.
A study was carried out on the use of Vernonia amygdalina del. extract to control fungi associated with groundnut (Arachis hypogeae L) seeds. Aspergillus niger van Tiegh, A. flavus link ex fries, Cercospora arachidicola Hori, Phoma exigua desm., Macrophomina phaseolina (Tassi) Goid, Fusarium oxysporium schl., Cercosporella sp and Phyllosticta sp were isolated from groundnut seeds obtained from Choba market in Rivers state. The water and ethanolic extracts of Vernonia amygdalina significantly (P=0.05) inhibited the spore germination and vegetative growth of Phoma exigua and Macrophomina phaseolina. Water extract was most active for Phoma exigua with an ED50 of less than 12.0%, followed by Macrophomina phaseolina 12.8%. The ethanolic extract showed fungitoxicity with ED50 of 13.2% (M. phaseolina) and ED50 of 15.9% (P. exigua). The results showed that Vernonia amygdalina leaf extract would be effective in controlling the leaf spot and charcoal rot of groundnut caused by Phoma exigua and Macrophomina phaseolina respectively.
Key words: Bitter Leaf Extract, Fungal Disease, Groundnut.