Effects of aqueous extracts of some plant species against Fusarium solani and Rhizoctonia solani in Phaseolus vulgaris plants

Abstract

The antifungal activity of aqueous extracts of 22 of plant species, against the linear mycelium of Fusarium solani and Rhizoctonia solani, were tested in vitro test. All plant extracts have an antifungal activity against the two fungi except Basil, Castor beans, Chamomile and Peppermint. Aqueous extracts of Chilli, Lantana, Lemon grass and Onion seeds highly reduced the mycelial growth of F. solani from 60.0 to 74.4% and of R. solani from 42.2 to 71.1%. These extracts at concentrations of 2.5% significantly inhibited the activity of polygalactronase and cellulolytic enzymes of the tested pathogenic fungi in treated cultural media compared with control. The dried plant materials of Chilli, Lantana, Lemon grass and Onion seeds were applied as seed dressing and/or soil treatment in greenhouse and field experiments. The treatments significantly reduced the incidence of pre- and post-emergence damping-off disease under artificial infection. Field results showed that the above treatments were effective in reducing the damping-off and root-rot disease incidence on bean plants under natural infection. The treatments increased the percentage of plant survival and improved some growth and yield parameters compared with control. The dried material treatments also increased the activity of polyphenol oxidase, peroxidase and chitinase enzymes in bean plants.