Evaluation of the Effects of the Extract of Vernonia amygdalina on Fungi Associated with Infected Tomatoes (Lycopersicon esculentum) in Jos North Local Government Area, Plateau State, Nigeria

Abstract

Aim: To evaluate the effects of different concentrations of ethanolic extract of Vernonia amygdalina on fungi associated with infected tomatoes (Lycopersicon esculentum) obtain from Jos North Local Government Area. Place and Duration of Study: Jos Local Government Area markets; Microbiology Laboratory, Federal College of Forestry between May and August, 2015. Materials and Methods: A total of thirty (30) infected tomatoes were collected. Three species of fungi were isolated, identified and observed in relation to their percentage of distribution. Isolates obtained were subjected to Vernonia amygdalina ethanolic leaf extract to determine antifungal sensitivity at varying concentrations. 70% Ethanolic extract of Vernonia amygdalina at 12.5, 25, 50 and 100 mg/ml were used for sensitivity test with positive control using fluconazole (50mg/ml) and negative control using distilled water. The mean effects of the treatments on the isolates were determined at 24hours and 48hours, respectively. Results: The percentage of distribution showed Geotrichum candidum (45.16%), Rhizopus stolonifer (22.58%) and Fusarium oxysporum (32.26%). After 24 hours, no inhibition was recorded on Fusarium oxysporum at all levels of concentration of the test plant, except the positive control which showed the highest inhibitory effect. However after 48 hours, there was inhibitory effect across all the isolates at all concentration levels of the test plant with significant differences between each level. 100 mg/ml of the extract had high inhibitory effect of 13.00 mm in comparison with other concentration levels. The lowest inhibitory effect of 1.00 mm was observed at 12.5 mg/ml concentration. The positive control showed no inhibitory effect on Rhizopus stolonifer within the duration of the observation. The inhibitory effects of the extract results shows significant difference among the three fungi tested (P<001). Conclusion: This study revealed that natural products from higher plants are relatively broad spectrum, bio-efficacious, economical, and biodegradable and can be ideal for use as agro-chemicals. Among plants that are known to possess those qualities is Vernonia amygdalina.