Effect of Azadirachta indica extract on the radial growth of some test fungi isolated from two varieties of cocoyam (Colocasia esculenta L.) corms and cormels in some markets in Plateau State, Nigeria

Abstract

Antifungal effect of aqueous and ethanol extracts of Azadirachta indica on the radial growth of fungal pathogens of stored cocoyam corms and cormels was investigated. Four different extract concentrations were used from the plant leaves. Pathogenicity test showed that: Alternaria alternata, Fusarium oxysporum, Verticilium lateritium, Botrydiplodia theobramae, Colletotricum coccoides, Phythium myriotylum, Fusarium verticillioides, Rhizopus stolonifer and Geotricum candidum induced rot in both varieties of healthy cocoyam corms and cormels after 7 days of inoculation. The highest aqueous extract inhibition recorded was 81.11% on V. lateritium at 10% while the least inhibitory effect was 18.35% observed at 2.5% on G. candidum. Meanwhile, the ethanol extract gave a highly significant (P<0.05) inhibitory effect of 87.21% at 10% and the least was 26.80% at 2.5% on A.alternata and V. lateritium respectively compared to the rest as recorded in aqueous extract at the same level of concentrations (10%). The fungitoxic potential of this plant extract on rot inducing fungi of stored cocoyam corms and cormels is indicative of its use to farmers as alternative to commercial or synthetic fungicides destroying our ecosystem and health.