Antifungal potencies of ethanol leaf extracts of four plants found around traditional Yan Barns in south eastern Nigeria on five Yam pathogens implicated in postharvest Yam rot

Abstract

The susceptibilities of five fungi implicated in postharvest rot of yam, namely, Aspergillus niger, Penicillium oxalicum, Mucor circinelloides, Fusarium oxysporum, and Rhizopus nigricans were evaluated using ethanol leaf extracts of four plants commonly found around traditional yam barns in south eastern. The plants screened were Fagara rubescens, Neubouldia laevis, Pterocarpus soyauxii, and Vernonia amygdalina. Antimicrobial susceptibility was measured as an index of turbidity of broth cultures after incubation 72 hours at ambient temperature (29 – 310C). The optical densities (OD650) were measured by spectrophotometry. None of the test isolates showed susceptibility to any of the plant extracts screened irrespective of the concentration employed. This study also revealed that though all the plants contained bioactive secondary metabolites, no antifungal potency was detected for any of the plant extracts on the test organisms.

Keywords

• yam pathogens, plant extracts, yam rot, susceptibility, phytochemicals