ANTIFUNGAL ACTIVITY OF PLANT EXTRACTS ON COMMON BEAN PATHOGENS

Abstract

Bioactive plants have been studied for their effectiveness in controlling plant diseases, for use in production systems that seek to reduce or eliminate the application of pesticides. This study aimed to evaluate the antifungal activity of plant extracts on common bean soilborne pathogens. We added aqueous extracts from the medicinal plants Baccharis dracunculifolia, Porophyllum ruderale and Schinus terebinthifolius and ethanolic extracts from B. dracunculifolia and Calendula officinalis to PDA (potato-dextrose-agar) in order to obtain the concentrations of 0, 250, 500, 1000 and 3000 µl L-1. Mycelial discs (5 mm diameter) of six fungus species (Fusarium oxysporum f. sp. phaseoli, F. solani f. sp. phaseoli, Macrophomina phaseolina, Rhizoctonia solani, Sclerotinia sclerotiorum and Sclerotium rolfsi) were aseptically placed in the center of Petri dishes with PDA. The colony diameter was measured after 48 h. The mycelial growth of the pathogens was not affected by the aqueous extracts of P. ruderale and S. terebinthifolius. Only aqueous and ethanolic extracts of B. dracunculifolia and the ethanolic extract of C. officinalis had inhibitory effect on the mycelial growth of the fungi. The mycelial growth was more pronouncedly reduced by the ethanolic extract of B. dracunculifolia than by the aqueous extract. We concluded that B. dracunculifolia and C. officinalis have potential to be included in further tests as a component of an integrated program for management of common bean pathogens.