Phytochemical composition and efficacy of ethanolic leaf extracts of some Vernonia species against two phytopathogenic fungi

Abstract

Phytochemicals in the form of ehanolic extracts of three Vernonia species viz., V. ambigua, V. amygdalina and V. cinerea were evaluated in vitro for their efficacy against Cercosporell apersica and Curvularia lunatus isolates of groundnut leafspot disease. The extracts at the concentrations of 100, 200, 300, 400 and 500 mg/mL were tested on Potato Dextrose Agar medium (PDAM) for their effect on radial mycalial growth. Maximum growth inhibition of C. persica was observed at 200 mg/mL for V. ambigua and 300 mg/mL for V. amygdalina and V. cinerea while maximum inhibition of C. lunatus was at 300 mg/ml for all the extracts. The extracts had superior inhibition effect over Dithane M45 in fungitoxicity against the pathogens. The phytochemical screening of the extract showed the presence of flavonoids, alkaloids, terpenes, saponins, tannins among others at varied concentrations while GC-MS analysis of the extract revealed a mixture of compounds which may be responsible for the observed biological activity. The exploitation of these extracts will greatly contribute to the available ecofriendly biofungicides in the control of plant diseases due to these fungi. © 376.