Uso de extractos acuosos de raquis de banano y Tagetes spp. enriquecidos con bacterias y hongos endofíticos para el control biológico de Radopholus similis (Cobb) Thorne

Abstract

Extractos acuosos de Tagetes spp. y raquis de banano en forma individual, mezclados y combinados con microorganismos endofíticos fueron estudiados en dos etapas para el biocontrol de Radopholis similis en vitro plantas de banano cv. "Gran enano". En la primera etapa se evaluó el efecto de extractos acuosos maduros y frescos de Tagetes spp y raquis de banano de forma individual y combinada para medir su efecto en la penetración y biocontrol de R. similis así como su efecto en la promoción de crecimiento. Mientras que para la segunda etapa se determinó el efecto de extractos de Tagetes spp. y raquis de banano enriquecidos con cuatro hongos y cuatro bacterias endofíticas en condiciones in vitro e in vivo para el control de R. similis; adicionalmente se evaluó el efecto individual de órganos de la planta de Tagetes spp. a nivel in vitro e in vivo.Los tratamientos raquis-bacteria (20 y 25 por ciento) y Tagetes-hongo (10 y 20 por ciento) fueron los más efectivos, con biocontroles mayores al 82 por ciento. A nivel in vitro los extractos de órganos de Tagetes spp. redujeron la movilidad de R. similis siendo los extractos de raíces y flores los que presentaron mayor inmovilización a las 24 horas alcanzando porcentajes hasta 92 por ciento. A nivel de invernadero los extractos de órganos de Tagetes spp. redujeron la penetración de R. similis entre 55 y 81 por ciento, siendo estadísticamente similar al XI control químico. Además extractos de raíz y flor fueron los que presentaron mayor promoción de crecimiento de la planta.

Aqueous extracts of Tagetes spp. and banana rachis along as well as in combinations with endophytic microorganism were evaluated in two phases for the biocontrol activity to Radopholus similis in tissue culture plants of the Grande Niane. In the first phase it was evaluated the effect of fresh and fermentated aqueous extracts of Tagetes spp. and banana rachis along and combined for their effect on the penetration and biocontrol of R. similis, as well as the plant growth promotion. In the second phase it was evaluated the effect of extract of Tagetes spp. and banana rachis enhanced with 4 endophytic bacteria and 4 endophytic fungi, which were tested in vitro and in vivo for the biocontrol of R. similis. In addition, the effect of the extract of different parts of the Tagetes spp. plant was also evaluated. In the first phase 14 treatments of extract of Tagetes spp. and banana rachis reduced the penetration of R. similis up to 70 and 90 percent.In greenhouse conditions the extract of Tagetes spp. and banana rachis reduced the population of R. similis in the root system up to 68 to 89 percent and the treatment of rachis enhanced with 20 a 25 percent of bacteria and Tagetes spp. with fungi 10 to 20 percent were the most effective reaching biocontrol activity higher than 82 percent. In vitro conditions extract of organs of plant of Tagetes spp. provoque the inmovilation of R. similis and extract from roots and flowers were more efficient than leaves and stems. It was found that at 24 hours of exposition 92 percent of R. simillis was inmovilizated. In greenhouse conditions the organs extract of Tagetes spp. reduced the penetration of R. similis between 55 to 85 percent and not difference XIII with the chemical control was found. Besides the biocontrol activity extract of roots and flower presented the higher effect on the plant growth promotion.