Mycoparasitic capabilities of diverse native strain of Trichoderma spp. against Fusarium oxysporum f. sp. lycopersici

The Fusarium wilt of tomato (Lycopersicon esculentum Mill.) caused by Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder and Hansen is recognised as one of the most devastating disease and major yield limiting factor in tomato growing regions worldwide. For eco-friendly and sustainable management of the disease, 19 Trichoderma native isolates belonging to 3 species of the genus, T. harzianum, T. asperellum and T. virens were evaluated in vitro against the pathogen using dual culture method. Out of 19 isolates, 8 isolates showed mycoparasitism, 8 isolates showed antibiosis and remaining showed lysis. Microscopic observations of Fusarium oxysporum f. sp. lycopersici (FOL) growth in dual cultures revealed that growth inhibition occurred just before near to contact with the antagonist. All T. harzianum isolates tested exhibited coiling around the hyphae of FOL. Isolates of T. harzianum, showed good coiling and growth inhibition of the pathogen. The T. harzianum strains did not differ in coiling pattern and gave somewhat equal coiling performances. Strains of T. asperellum, showed coiling but the coiling pattern of all these strains was different. Only one strain of T. virens showed coiling out of 2 strains. Among them T. harzianum (SVPUTh91) showed the best performance in vitro as biological control agent against FOL followed by T. asperellum and T. virens, resulting in 83, 73 and 65% reduction in colony growth, respectively.