Characterization of the Midgut Bacterial Isolate of Culex quinquefasciatus and Its Control by Plant Extracts

Abstract

In the present study, the midgut bacteria of Culex quinquefasciatus was isolated, characterized and controlled by plant extracts. Morphology of the bacterial colony was studied. The vegetative body of the bacterial isolate was scanned in scanning electron microscope. Biochemical tests and fermentation tests of different carbohydrate sources were performed. The physiological tests such as temperature, NaCl and pH tolerance ability of the midgut isolate of Cx. quinquefasciatus was determined. The antibiotic sensitivity of the bacterial isolate against some standard antibiotics was observed. Agar cup assay was performed to determine the sensitivity of the isolate against some plant extracts such as Neem ( Azadirachta indica ), citronella ( Cymbopogon nardus ) and Basak ( Justicia adhatoda ). From the morphological, biochemical and physiological characteristics, the midgut bacterium CMG1 was characterized as Bacillus sp. the isolate CMG1 showed sensitivity to Neem ( Azadirachta indica ) and citronella ( Cymbopogon nardus ) plant extracts. The application of neem and citronella (25 μl/well) produced 32 and 45 mm inhibition zone of the midgut bacterial isolate CMG1.