The efficacy of some native Trichoderma isolates in induction of resistance in tomato against Fusarium oxysporum f. sp. lycopersici, the causal agent of Fusarium wilt disease

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) is one of the most destructive tomato diseases. The disease control through induction of resistance by biocontrol agents is a management strategy to reduce application of chemical fungicides. So, in this study the efficacy of 10 native Trichoderma isolates in induction of resistance against the pathogen was evaluated. In greenhouse, phenotypic evaluation of induction of resistance by Trichoderma isolates with stem-injection and split-root bioassay methods showed the least disease severity and incidence significantly (p≤0.05) in Trichoderma harzianum Th-14ᚉ and Trichoderma atroviride Ta-30ᚉ treatments. The results of study of rhizosphere colonization ability of Trichoderma isolates by serial dilution method, revealed maximum population density in these two isolates. The disease severity showed negative correlation with Trichoderma population density. The activity of polyphenol oxidase and peroxidase increased significantly (p≤0.05) in the plants treated with Th-14 and Ta-30 isolates compared to control (Fol). The results of this study can be applied in integrated management of tomato Fusarium wilt.