Examinando por Materia "Entomopathogen"

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  • Miniatura
    PublicaciónAcceso abierto
    Evaluation of Beauveria bassiana for Monalonion velezangeli (Hemiptera: Miridae) control in coffee crop.
    (Universidad del Valle, 2020-07-09) Góngora, Carmenza E.; Laiton J., Laura A.; Gil, Zulma N.; Benavides, Pablo; Montoya Lerma, James
    Monalonion velezangeli (Hemiptera: Miridae) is a polyphagous pest found in Colombia which attacks ornamentals, weeds, timber and fruit trees including coffee. The pathogenicity of Beauveria bassiana strain B at 1 x 107 conidia/ml was evaluated on Monalonion velezangeli by immersion. The fungus caused 84 % mortality on the insect. Cissus verticillata plants were infested with M. velezangeli and applications of the fungus at 4 x 1010 conidium/L were done. Average insects mortality treated with the fungus was 84 %. Under field conditions, in the department of Huila, in a coffee plot infested with M. velezangeli the following treatment were applied: strain B at 4 x 1010 conidium/L, insecticide Chlorpyrifos at 4 cc/L and water. In a first assay, groups of nine trees (20 repetitions) were chosen. Both the insecticides and the fungus caused insect mortality with an 80 to 90 % decrease in the percentage of trees with new damage. Meanwhile the decrease in the control was 40 %. In a second assay, three plots of 450 trees were selected and the same treatments were applied. Percentage of trees affected in the control ranged between 19 and 11 %. The plot in which the insecticide was applied, started with an infestation of 29 %, and at the end of the assay the infestation was 20 % and the highest damage was observed in this plot. In the plot where B. bassiana was applied the initial infestation was 30 % and at the end of the assay, this plot showed the lowest infestation level near to 5 %. The B. bassiana strain B becomes a feasible alternative for M. velezangeli pest control on coffee plantations.
  • Miniatura
    PublicaciónAcceso abierto
    Hypothenemus hampei (Coleoptera: Curculionidae) as in vitro inducer of laminarinase and chitinase of Beauveria bassiana (Hypocreales: Clavicipitaceae).
    (Universidad del Valle, 2017-06-30) Acuña Payano, Rosalyn; Quiroz Farfán, Diego; Laynes Zela, Pedro; Nolasco Cárdenas, Oscar; Gutiérrez Román, Ana; Sociedad Colombiana de Entomología - Socolen; Universidad del Valle
    In Peru, Hypothenemus hampei or the coffee berry borer, (CBB) is the most important pest, causing specific damage to coffee crops, because it causes fruit to fall during feeding. On the other hand, Beauveria bassiana is an entomopathogenic fungus widely used in biological control. This study determine the induction of chitinase and laminarinase of B. bassiana in presence of H. hampei powder and how it relates to pathogenicity in order to promote the development of biological control agents and replace the use of pesticides. Three different liquid media cultures were prepared to induce the enzymatic production and growth of B. bassiana; and biomass, total proteins, conidia, enzymatic activities and enzymatic specific activities were evaluated. Data were analyzed using SPSS 19.0. Significant differences (P < 0.05) for biomass (F = 5.30; df = 35; P < 0.05), conidia (F = 190.87; df = 35; P < 0.05), total proteins (F = 91.04; df = 35; p < 0.05), laminarinase activity (F = 27.61; df = 35; P < 0.05), specific laminarinase activity (F = 25.31; df = 35; P < 0.05), chitinase activity (F = 32.66; df = 35; P < 0.05) and specific chitinase activity (F = 26.91; df = 35; P < 0.05) were determined between each treatment evaluated. Levels of chitinase and laminarinase determined that induction of these enzymes is possible in liquid media cultures supplemented with powdered H. hampei extract. Results require further evaluation for application in vivo but are fundamental and constitute a contribution to knowledge about the pathogenic mechanism of B. bassiana.