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Accueil du site → Master → Canada → Investigations on the use of the fungus, Beauveria bassiana, Hyphomycetes : Moniliales, for control of the Senegalese grasshopper, Oedaleus senegalensis , Orthoptera : Acrididae

Simon Fraser University (1993)

Investigations on the use of the fungus, Beauveria bassiana, Hyphomycetes : Moniliales, for control of the Senegalese grasshopper, Oedaleus senegalensis , Orthoptera : Acrididae

Ouedraogo, Maneguedo Robert

Titre : Investigations on the use of the fungus, Beauveria bassiana, Hyphomycetes : Moniliales, for control of the Senegalese grasshopper, Oedaleus senegalensis , Orthoptera : Acrididae

Auteur : Ouedraogo, Maneguedo Robert

Université de soutenance : Simon Fraser University

Grade : Master of Pest Management (M.P.M.) 1993.

Résumé
The Senegalese grasshopper, Oedaleus senegalensis (Orthoptera : Acrididae), is a major pest of crops in the sahelian zone of West Africa. Ten new isolates of Beauveria bassiana (Hyphomycetes : Moniliales) were obtained from soil and grasshoppers collected in Burkina Faso, from zones of significant grasshopper and locust activity. The effects of temperature on conidial germination and pathogenicity toward O. senegalensis were investigated under laboratory conditions. Germination was studied at temperatures of $\rm 20\sp\circ,\ 25\sp\circ,\ 30\sp\circ\ and\ 35\sp\circ C.$ The most favorable and the most adverse temperatures were 25$\sp\circ$ and 35$\sp\circ$C, respectively. Temperature response curves for the germination rate and the time to 95% germination were adequately described by quadratic functions. Intra-specific variations in the components of germination were observed. Pathogenicity was assessed after topical application of 10$\sp5$ conidia onto third-instar nymphs. All isolates were found to be pathogenic to O. senegalensis. Significant differences in virulence were observed among isolates, and the median lethal times varied between 3.5 and 5 days. High virulence appeared to correlate with high conidial germination. The effects of oral and topical applications of conidia on third-instar nymphs were compared. The fungus was pathogenic to O. senegalensis regardless of the route of exposure. In addition, there was no significant difference in virulence between the two methods of application. These studies show that (1) B. bassiana has potential use for control of grasshoppers, (2) influence of temperature on germination should be considered when selecting isolates to develop as a mycopesticide in the Sahel, (3) selection for virulent isolates is necessary, even among isolates collected from the same geographical location, and (4) conidia could be used in baits or droplets in a similar way as chemical pesticides for control of O. senegalensis.

Présentation (Amicus)

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