Antagonistic mechanisms of Trichoderma spp. as biological control systems for the management of Fusarium oxysporum f. sp. mori in blackberry and raspberry cultivars

Abstract

The fungal genus Fusarium is one of the most agriculturally important pathogenic groups. This filamentous ascomycete fungi can be found all over the world and includes many toxin-producing plant pathogens. Traditional methods that aid in the control of the disease are being questioned as they are becoming ineffective in the management of the disease. Biocontrol agents are an innovative solution that are becoming more and more significant to the agricultural sector as an alternative to fungicides or more classical methods. Different species of Trichoderma have been described as optimal candidates to control F. oxysporum. However, their effectiveness depends on the forma specialis of the pathogen. A study was undertaken under in vitro conditions to assess the antagonic mechanisms of seven Trichoderma strains, against 6 vascular wilt causing pathogen in blackberry and raspberry plants, Fusarium oxysporum f. sp. mori. By the method of dual culture plate technique, the antagonic mechanisms and the production of volatile organic compounds of the isolates of Trichoderma were screened under in vitro conditions against Fusarium oxysporum f. sp. mori. All strains, antagonic and pathogenic, where resistant to the highest concentration recommended by the manufacturer (Sygenta) to Uniform and Ridomil Gold. Antibiosis, mycoparasitism, and competition for resources was observed micro- and macroscopically in all dual culture antagonism screening. As well as mycelial growth inhibition up to 82% by the Trichoderma strain T2. Production of inhibitory volatile compounds was confirmed by a sealing agar plate system where maximum growth inhibition was achieved (32%) by the Trichoderma strain T2. The F. oxysporum strain F1, was the hardest to inhibit, with a minimum percentage of inhibition of in dual culture antagonism. All the Trichdoerma isolates demonstrated a significant reduction in the growth of the Fusarium isolates. The results obtained in this study showed the antagonistic potential of the Trichoderma strains and how its mechanisms can aid in the biological control of the pathogen Fusarium oxysporum f. sp. mori. The potential use of these biocontrol agents can improve management strategies of Fusariosis in blackberry and raspberry cultivars.