Advances in Life Sciences
Year : 2016, Volume : 5, Issue : 6
First page : ( 2049) Last page : ( 2052)
Print ISSN : 2278-3849. Online ISSN : 2278-4705.

Entomopathogens Against Cowpea Bruchid, Callosobruchus maculatus (F.) (Chrysomelidae: Coleoptera) in Storage

Kumari S. Amritha

College of Agriculture, Vellayani. email: amritha2005kau@gmail.com

Online published on 15 December, 2016.

Abstract

Activity of two entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against Callosobruchus maculatus in storage was assessed by conducting studies on dosage-mortality response and time-mortality effect in the laboratory. Toxicity of entomopathogens was studied by two bioassay techniques-direct dipping and residue film. The entomopathogens were tested at five different concentrations 1 x 10⁴, 1 x 10⁵, 1 x 10⁶, 1 x 10⁷ and 1 x 10⁸ spores/ml. Observations on mortality were taken at 24hours interval upto five days. Resultson mortality of C. maculatus indicated an increase in mortality withincrease in dosage and period of exposure. Probit analysis of dosage-mortality response of B. bassiana and M. anisopliae indicated lower LC₅₀ value for M. anisopliae than B. bassiana (5.12x10⁶ and 6.7x10⁶ spores/ml) than B. bassiana (5.38x10⁶ and 7.49x10⁶ spores/ml). Time-mortality effect of B. bassiana and M. anisopliae indicated an increase in LT₅₀values as the spore concentration decreased.

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Keywords

Callosobruchus maculatus, Beauveria bassiana, Metarhizium anisopliae, LC₅₀, LT₅₀.

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