Abstract Mycoparasitic action of Trichoderma spp. on the pathogen through the production of lytic enzymes viz β-1, 3 glucanase (laminarinase) and chitinase was studied. Hyphal interaction between the antagonist and the pathogen was investigated through scanning electron microscope. Coiling around, penetration and overgrowth of the antagonistic mycelium on the pathogenic mycelium were the result of the death of the pathogen mycelium through lysis. Studies on the production of hydrolytic enzymes viz. β-1, 3 glucanase and chitinase by the five Trichoderma spp. have reflected their inducible nature. On the other hand, various carbon sources influenced differently the production of β-1, 3 glucanase and chitinase enzyme by the antagonists, as there exists a parallel relationship between carbon source in the medium and Trichoderma species. Different species of Trichoderma also showed variable degrees of enzyme production and T. harzianum was recorded to be the most efficient producer. The variation in enzyme activity clearly reflects the varying degree of substrate utilization by the different species of Trichoderma indicating thereby their varying degree of biocontrol potential as mycoparasitic fungi.
Keywords Fusarium oxysporum, hyphal interaction, lytic enzymes, mycoparasitism, Trichoderma species.