CONICET | Buscador de Institutos y Recursos Humanos

Introduction: The fungi of the genus Fusarium are pathogens of plants widely distributed worldwide, affecting more than 80 crops of commercial importance. These phytopathogens produce significantlosses in the agricultural and forestry activity of the province of Misiones (Argentina). For its control traditional chemical pesticides are extensively used, which usually have many detrimental consequences on the environment, for this reason, the use of biopesticides of fungal origin is increasingly widespread. Among the main fungal genera used in biocontrol are Trichoderma and Clonostachys. Species of the genera Trichoderma and Clonostachys are used for biological control due to their ability to inhibit fungal pathogens through different mechanisms of action, such as mycoparasitism and the secretion of secondary growth inhibiting metabolites.Objective: In order to develop optimal biocontrol strategies, the aim of this work was to evaluate the in-vitro pathogenicity and biocontrol capacity of two native strains of Trichoderma, and one native strain of Clonostachys against a strain of a phytopathogenic fungus of the genus Fusarium.Methods: Each fungal isolate, the biocontrol fungi Trichoderma (POS 7 and Tricho H), Clonostachys (HEP30), and the phytopathogenic fungus Fusarium (LBM 232), were reactivated in a 60 mm Petri dish, containing PDA as a culture medium at a concentration of 3.9% (w/v), sterilized in an autoclave at 121°C, and 1 atm pressure higher than normal for 15 min.For antagonisms, 90 mm diameter Petri dishes were used with PDA medium 3.9% (w/v). Five millimeters wells were made in the plates under sterile conditions, and 50 µL of the spore suspensions of each of the strains, with concentrations of 10 spores/mL, were inoculated in each well. The plates were incubated at 28 ± 1°C, with controlled photoperiod (24h darkness) for a period of 10 days. As an experimental control, all the isolates of the biocontrol strains and phytopathogenic fungi were cultured in the absence of the antagonist fungus where 50 µL of each spore suspension were seeded in a well located in the center of each plate. From all these tests, photographic records of each confrontation were obtained daily to determine the diameter of colonial growth of each fungus. The diameter of growth was analyzed statistically using Statgraphics Centurion Software.Results: The results obtained from contrasting the growth halos showed a reduction of Fusarium Colony. In all cases, the biocontrol agents of the genus Trichoderma were more aggressive and faster in their development, covering the entire plate faster than the Clonostachys HEP30 biocontrol agent. Even growing on the phytopathogen colony. Although the growth of Clonostachys was slower, its mere presence produced the deformation of the growth halos of Fusarium.Conclusions: Thus, it can be suggested that the native strains of Trichoderma and Clonostachys genera cocultured possess an effective biocontrol capacity against the Fusarium phytopathogen.

enviar mensaje