Antifungal activity of chitosan against Fusarium oxysporum isolated from Vanilla planifolia Andrews.

Vanilla planifolia is an orchid with high commercial demand, due to the fact that vanillin is obtained from its siliques, which is a substance used worldwide mainly in the cosmetic and soft drink industry. The vanilla crop is mainly affected by the fungus Fusarium oxysporum that causes fruit and root rot and in more severe cases causes the death of 52% of the plants. Chitosan is a biopolymer that stands out for interacting with the cell wall of pathogenic microorganisms, inhibiting their growth. Therefore, the isolation of the fungus F. oxysporum from plants with signs of disease began. Mycelial growth inhibition bioassays were performed in solid PDA medium, adding chitosan at different concentrations (1, 1.5, 2, 3, 4%), making evaluations every 24 hr until the control fungus covered the surface of the plate. The statistical results showed that the dose of chitosan at 4% produces an inhibition of fungal growth by 76.32% in relation to the control. In the feasibility study it was determined that the germination of F. oxysporum spores was significantly affected in the presence of 3% and 4% chitosan. [ABSTRACT FROM AUTHOR]