In vitro evaluation of antifungal activity of Ageratum conyzoides, Basella alba and Mitracarpus villosus on the strain of Lasiodiplodia theobromae in the Kisangani Region / D R Congo

Abstract

Following our previous investigations relating to the in vitro evaluation of antifungal activity, this study focused on the demonstration of the inhibitory power of extracts of fresh and dry leaves of Ageratum conyzoides, Basella alba and Mitracarpus villosus on the strain of Lasiodiplodia theobromae, fungus responsible for brown rot of cocoa pod in the Kisangani region. In six repetitions on the Patato dextrose agar medium, the strain of L. theobromae was inhibited up to 68.1% by the aqueous extract of B. alba; 60.0% by the ethanolic extract of A. conyzoides and 55.2% by the ethanolic extract of M. villosus (all obtained from dry leaves). Only the fresh leaves of the aqueous (56.7%) and ethereal (51.1%) extracts of A. conyzoides showed high inhibition percentages compared to those of the extracts of the fresh leaves of B. alba and M. villosus. The extracts of the dry leaves showed high inhibition percentages followed by those of the fresh leaves and finally those of crude extracts after two days of incubation. Thus, in addition to the expected results, the plants studied are all active. These inhibitory powers could be very high for the secondary metabolites of the respective plants.