Bioassay of Lemongrass on Fungi Pathogen Associated with Cassava Tubers Rot in Farin Gada Market, Jos

Abstract

The aim of this study was to determine the effects of Lemongrass on fungal pathogen associated with cassava tuber rot. The study was carried out in the biology laboratory of the Federal College of Forestry Jos, Plateau state from March to May, 2019. Rotten and healthy cassava tubers were collected separately from Farin-Gada market Jos, fungi species were isolated from rotten cassava tubers by direct inoculation of the spoiled part on sterile Potato Dextrose Agar medium and incubated for 3-5 days, the isolated fungi were identified microscopically and macroscopically. The identified fungi were used for pathogenicity test. The antifungal effect of different concentrations of ethanol extract of lemongrass was investigated. Data collected were analyzed using one way ANOVA and the means were separated using Least Significant Difference (LSD) at (p≥0.05). The fungi isolated include, Fusarium sp, Penicillium sp, Geotrichum candidum, and Aspergillus flavus. The frequency of occurrence of the isolated fungi indicated Fusarium sp, Penicillium sp, Geotrichum candidum, and Aspergillus flavus had 30, 15, 35 and 20% respectively. 20 mL of the tested extract gave the highest inhibition of 19.07, 20.57, 18.17 mL and 18.00 mL on Fusarium spp, Penicillium spp, Geotrichum candidum and Aspergillus flavus respectively. At the 5th day of incubation the results of the pathogenicity showed that Aspergillus flavus gives the highest deterioration of 9.17 mm. The length of deterioration showed significant difference. The lemongrass extract indicated anti-fungal effect on the fungal isolates, therefore could be used to control cassava tuber rot caused by fungi.