Efficacy of Jatropha, Annona and Parthenium biowashon Sclerotium rolfsii, Fusarium oxysporum f. sp. ciceriand Macrophomina phaseolina, pathogens of chickpeaand sorghum uri icon

abstract

  • The demand for products and technologies based on plants to control plant pathogens has increased inrecent years due to concern about the use of hazardous pesticides. In the present investigation,washings of vermicompost (called biowash) prepared from foliage of Jatropha (Jatropha curcas),Annona (Annona squamosa) and Parthenium (Parthenium hysterophorus) were evaluated againstfungal pathogens viz. Fusarium oxysporum f. sp. ciceri (FOC; causes wilt in chickpea), Sclerotiumrolfsii (causes collar rot in chickpea) and Macrophomina phaseolina (causes charcoal rot in sorghum).Crude biowash of the botanicals were partitioned against ethyl acetate and the resultant organic andaqueous fractions were tested against the fungi. Similarly, crude biowash was also passed through C18solid phase extraction cartridges and the resultant adsorbed and non-adsorbed fractions were testedagainst the fungi. Organic fractions of all the three biowash at 0.5% inhibited the growth of S. rolfsiibetween 78 and 87%, M. phaseolina between 62 and 65%, whereas only Parthenium was able toeffectively inhibit FOC (91%), compared to control. Adsorbed fractions of all the three biowash at 0.5%inhibited the growth of S. rolfsii between 81 and 92%, M. phaseolina between 76 and 77% and FOCbetween 26 and 49%, compared to control. Both aqueous and non-adsorbed fractions of all the threebiowash did not inhibit any of the fungi. Since Jatropha biowash showed consistently higher levels ofinhibition (>80%) in both fractionation methods on S. rolfsii, this was selected for further purification oftheir secondary metabolites. When the organic fraction of Jatropha biowash was further fractionated byC18 open column chromatography with eluent 5, 10, 20, 40, 60, 80 and 100% MeOH fractions, only 80%methanol (MeOH) fraction was found to inhibit S. rolfsii. The active 80% MeOH fraction showed threeclear bands when chromatographed on Silica Gel 60 F254 thin layer chromatography (TLC) plates with Rfvalues 0.95, 0.90 and 0.70. Hence, it was concluded that one of these three bands could be the activeingredients that inhibited S. rolfsii and can be further exploited as a bio-fungicide

publication date

  • 2010