DETERMINACIÓN DE LA FUENTE DE INOCULO DE Claviceps gigantea PARA LA EXPRESIÓN DE DIENTE DE CABALLO EN EL HIBRIDO FAISÁN

Abstract

The incidence and damage caused by the fungus Claviceps gigantea has increased considerably in the Toluca Valley region. It has been reported in fields of susceptible maize hybrids at altitudes from 2,000 to 2,800 masl, especially in plots under high productivity programs. The objective of this study was to identify the source of the inoculum leading to the expression of Claviceps gigantea in the Faisán® hybrid, evaluating different concentrations of ascospores and microconidia (500,000; 250,000; 100,000 and 50,000). The study consisted of two stages. The first was performed in the laboratory, to obtain solutions at the different experimental doses, and the second was performed in the field, where plants that were considered ideal for inoculation were inoculated using the injection technique. For each inoculum type and concentration, 5mL were injected per plant. The results showed that the source of inoculum was ascospores, and 100,000 was the dose that led to the highest incidence and most severe degree of horse’s tooth; the incidence of ears affected increased by 50%, and sclerosis formed by 40 days. Thus, this type of spore demonstrated an ability to generate a new inoculum, reproductive structures, and/or spores in a shorter time period.