Mechanisms in the biological control of lentil vascular wilt (Fusarium oxysporum f.sp lentis) by Trichoderma hamatum

Biological control with microorganisms is a promising method for managing lentil vascular wilt. The efficacy of T hamatum for control of F oxysporum was investigated both in vitro and in vivo. In vitro, T hamatum rapidly colonized and produced abundant conidia on F. oxysporum in a dual culture plate assay. Microscopic studies showed different hyphal interactions of effective T hamatum towards the pathogenic fungus. The biocontrol fungus T hamatum appears to be a mycoparasite of F oxysporum hyphae. In vivo, soil treatment with T hamatum significantly increased the population of T hamatum to be effective and reduced the population of F oxysporum. T hamatum was a strong competitor, even at fairly low concentration, in the rhizosphere with F. oxysporum in loamy soil. The results of this study suggest that mycoparasitism and competition is one of the mechanisms involved in the inhibitory interaction of F oxysporum with T hamatum.