Isolation of antagonistic fungi and evaluation of antifungal activity of the separated metabolite against the red rot of sugarcane pathogen

Antagonistic potential of six rhizosphere soil fungi viz., Trichoderma harzianum, T. viride, Aspergillus flavus, A. fumigatus, A. niger, and A. sulphureus were tested against the red rot of sugarcane pathogen Colletotrichum falcatum. Out of the seven soil fungi tested, Trichoderma harzianum was found to be most effective in controlling the growth of Colletotrichum falcatum based on the colony interactions and effects of volatile and non-volatile metabolites. When HPLC fractionation of the mycelia extract of T. harzianum, T. viride, Aspergillus flavus, A. fumigatus, A. niger, and A. sulphureus were tested against the red rot of sugarcane pathogen C. falcatum. The T. harzianum peak at showed RT 4.893 maximum antifungal activity with the inhibition zone of 0.9 mm followed by Trichoderma viride(0.7mm), A. fumigatus (0.5 mm), A. niger (0.5mm), A. flavus ( 0.4 mm), and A. sulphureus (0.3mm). This peak may be responsible for the antifungal activity of this fraction. The fungus isolated in the present study may be exploited commercially to biocontrol this disease. Further studies on the determination of the actual biochemical compound responsible for antagonistic effect through FT-IR and GC-MS analysis is under way.