Entomopathogenicity of beauveria bassiana and metarhizium anisopliae to the cowpea aphid,aphis craccivora koch (homoptera: Aphididae) |
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Authors: | Sunday Ekesi Abubakar D Akpa Isa Onu Michael O Ogunlana |
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Institution: | 1. Department of Crop Protection , Ahmadu Bello University , P.M.B. 1044, Zaria, Nigeria;2. International Centre of Insect Physiology and Ecology (ICIPE) , PO Box 30772, Nairobi, Kenya Fax: E-mail: sekesi@icipe.org;3. Department of Crop Protection , Ahmadu Bello University , P.M.B. 1044, Zaria, Nigeria |
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Abstract: | The pathogenicity of four isolates each of the entomopathogenic fungi, Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) Sorok. to apterous adult Aphis craccivora Koch was evaluated in the laboratory at 4 concentrations of conidia. All fungi isolates tested were found to be pathogenic to the insect but their virulence varied among species and isolates within species. Three isolates, B. bassiana CPD 11 and M. anisopliae CPD 4 and 5 caused significantly higher mortality than the other isolates at the various concentrations tested causing mortality of between 58–91%, 64 to 93% and 66–100%, respectively, at 7 days post treatment. At the highest concentration of 1 × 108conidiaml‐1, these isolates produced the shortest LT50s of 3.5, 3.6 and 3.4 days, respectively. Their LC50s were 6.8 × 105, 3.1 × 105 and 2.7 × 105 conidia ml‐1, respectively. The results indicate that these isolates are promising candidates for the control of the cowpea aphid but their pathogenicity to various aphid non‐target beneficial organisms within the cowpea agroecosystem warrant further investigation before initiating field control. |
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Keywords: | Aphis craccivora Metarhizium anisopliae Beauveria bassiana pathogenicity control cowpea |
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