<p>Actualmente, en los municipios del departamento de Nariño (Colombia), en los cultivos de trigo y papa que son los principales sistemas de producción, se presentan altas infestaciones de poblaciones de chisas encontrándose hasta 350 larvas/m2, representando un factor limitante para la producción de los cultivos. Una alternativa promisoria para el manejo de esta plaga es la utilización de métodos biológicos que incluyen el uso de hongos entomopatógenos. El objetivo del presente trabajo fue el de evaluar el efecto de <em>Beauveria bassiana, Metarhizium anisopliae </em>sobre larvas de <em>Ancognatha scarabaeoides </em>en laboratorio e invernadero. Los aislamientos de hongos se obtuvieron de larvas infectadas en los municipios de Yacuanquer y Ospina. En el laboratorio, se seleccionaron 5 de 9 aislamientos de hongos: Mt1, Bb cosmo, Mt2, Bb4 y Bb10 que presentaron mortalidades superiores al 50%, éstas se evaluaron a concentraciones de 1x105 a 1x1010 esporas/ml. El porcentaje acumulado de mortalidad a los 18 días después de la inoculación fueron: del 100% para Bb cosmo, Mt1 y Mt2 en la concentración de 1x1010 esporas/ml y del 90% para Bb4 y Bb10 en la concentración de 1x109 esporas/ml, presentando concentraciones letales 90(CL90) de 1.1x1010, 7.3x109, 2.2x1010, 3.9x1010 y 4.3x1010 esporas/ml respectivamente. En invernadero se evaluaron los mismos microorganismos con sus respectivas concentraciones letales 50(CL50) y 90(CL90), encontrándose porcentajes de mortalidad del 76.00%, 67.50%, 63.50%, 59.00% y 53.50% para Mt1, Bb cosmo, Mt2, Bb4 y Bb10. Estos resultados indican la posibilidad de incluir estos biocontroladores nativos en el manejo integrado de las chisas en Nariño.</p><p> </p><p><strong>Evaluation of the biocontrol activity of <em>Beauveria bassiana, Metarhizium anisopliae</em>, on larvae of <em>Ancognatha scarabaeoides </em>(Coleoptera: Scarabaeidae).</strong></p><p>High grub populations of coleopteran, frequently attack crops of wheat and potato in the Department of Nariño, Colombia. Reports indicate that infestations levels reach more than 350 larvae/ m2, which severely reduce crop yields. Use of biological control measurements as fungal entomopathogens seems to be a promising alternative for management of this pest. The present work aimed to evaluate the effect of <em>Beauveria bassiana </em>and <em>Metarhizium anisopliae </em>on larvae of <em>Ancognatha scarabaeoides </em>both in laboratory and greenhouse conditions. Isolates of entomopathogen fungus were obtained from infected larvae in the municipalities of Yacuanquer and Ospina. A sample of 5 isolates, which previously had shown to cause mortality rates higher than 50%, was selected in the laboratory: Mt1, Bb cosmo, Mt2, Bb4 and Bb10. Isolates concentrations from 1x105 to 1x1010 spores/ml were tested. The cumulative mortality percentage (at 18 days after the inoculation) ranged from 100% with Bb cosmo, Mt1 and Mt2 at concentrations of 1x1010 spores/ml to 90% with Bb4 and Bb10 at concentrations of 1x109 spores/ml. Lethal doses 90 (LD90) of 1.1x1010, 7.3x109, 2.2x1010, 3.9x1010 and 4.3x1010 spores/ml were calculated for each isolate, respectively. An evaluation of the biocontrol activity of the isolates was carried out under greenhouse conditions. Mortality percentages obtained reached 76%, 67.5%, 63.5%, 59% and 53.5% for Mt1, Bb cosmo, Mt2, Bb4 and Bb10, respectively. These results suggest that the use of native biocontrolers is a promising alternative to be included in the integrated management for white grubs in Nariño.</p>
Existence of entomopathogen fungi, Beauveria bassiana as an endophyte in cacao seedlings