Evaluation of different combinations of Trichoderma species for controlling Fusarium rot of lentil

The Fusarium disease, caused by Fusarium oxysporum has been observed in different areas of Iran in recent years. Current biocontrol studies have confirmed the effectiveness of the Trichoderma species against many fungal phytopathogens. In this study, biocontrol effects of Trichoderma isolates alone and in combination were evaluated against F. oxysporum pathogen. This study shows the ability of Trichoderma harzianum isolates which had been isolated from soil and as such, lentil roots were compared to the combination of the three fungal lentil Fusarium root. Three isolates (T. harzianum) T1, (Trichoderma asperellum) T2, (Trichoderma virens) T3, were selected base on good antagonist effect after screening tests for antifungal combination effects against Fusarium disease pathogen in greenhouse. In dual culture tests, three (T1, T2 and T3) isolates covered and colonized the colony of the pathogen. In other experiment, three (T1, T2 and T3) isolates covered and colonized the colony of the other Trichoderma isolates. Microscopic studies revealed hyphal coiling (hyperparasitism) of isolates T1 and T2 around F. oxysporum hyphae. Volatile metabolites of all isolates reduced the mycelial growth of fusarium pathogen. T1 and T2 isolates and their combination were more effective than other treatments in controlling the disease, such that it reduced disease severity from 20 to 44% and increased the dry weight from 23 to 52%. All treatments showed significant differences with control plants. Key words: Fusarium rot, lentil, combination, Trichoderma, biocontrol.