EVALUATION OF ANTAGONISTIC POTENTIAL OF INDIGENOUS TRICHODERMA ISOLATES AGAINST PYTHIUM APHANIDERMATUM (EDSON) FITZ. CAUSING RHIZOME ROT IN TURMERIC (CURCUMA LONGA L.)

Abstract

Twenty two isolates of Trichoderma spp. isolated from the turmeric rhizosphere soil collected from major turmeric growing tracts of South India were evaluated for their antagonistic potential against Pythium aphanidermatum (Edson) Fitz. causing rhizome rot of turmeric (Curcuma longa L.). The isolates were evaluated based on the dual plating, growth rate and volatile and non-volatile metabolites production in vitro. Out of twenty two isolates, six isolates via, IISR CLT 102, IISR CLT 107, IISR CLT 110, IISR CLT 114, IISR CLT 118, and IISR CLT 121 showed mycelial inhibition of above 70% on dual plate assay. The isolates showed variability in the production of volatile and non volatile metabolites. The highest inhibition by volatile metabolites was shown by IISR CLT 118 (84.82%) and IISR CLT 121(82.22%). The non-volatile metabolites produced by IISR CLT 103 (37.78%), IISR CLT 107(38.52), IISR CLT 110 (46.30%) and IISR CLT 114 (42.22%) were comparatively effective against the pathogen. IISR CLT 114 from Bidar (Karnataka) and IISR CLT 102 from Vaithiri (Kerala) induced cytoplasmic coagulation of the pathogen on dual culture technique. A total of six isolates were shortlisted for further evaluation in pot culture and field evaluation against rhizome rot of turmeric considering their above listed potentialities.