Fusarium oxysporum, agente causal de la marchitez de estevia en Veracruz, México

The wilting of stevia plants (Stevia rebaudiana Bertoni) is one of the most important phytosanitary problems in the production area of Veracruz. The objective of this study was to identify the causal agent of wilt symptoms in stevia plants in a plantation located in Martinez of the Torre, in the state of Veracruz, Mexico. In 2015, Stevia plants were observed and collected with symptoms of root rot, basal stem necrosis and wilting. From the samples, Fusarium fungal colonies were continuously obtained. For the identification of the fungus, a morphological characterization and sequence analysis of the region of the transcribed internal spacer (ITS) and of the partial sequence of the gene of elongation factor 1-alpha (EF1-α) were performed. In addition, the pathogenicity of a representative isolate of Fusarium in stevia plants was verified. The results of the morphological characterization, analysis of ITS and EF1-α sequences, as well as the pathogenicity tests, determined that Fusarium oxysporum is the causal agent of the wilt symptoms of stevia plants in Martinez of the Torre, Veracruz.