Microbial flora in gut of Culex quinquefasciatus breeding in cess pits.

The number and types of microorganisms in the gut of Culex quinquefasciatus larvae varied considerably from one site of collection to another. Larval gut, in general, contained enormous number of bacteria, a few fungi and negligible number of actinomycetes which belonged to 15 bacterial, 6 fungal and 4 actinomycete genera, respectively. Bacillus sp., Staphylococcus sp. and Pseudomonas sp. among bacteria, Aspergillus among fungi and Streptomyces sp. among actinomycetes were frequently encountered. Escherichia, Proteus, Aspergillus and Streptomyces were the most abundant genera. Isolates of Bacillus, Pseudomonas, Shigella and Staphylococcus caused 100% mortality during the early instar of larval development. None of the fungal isolates effected 100% mortality while Nocardiopsis sp. among actinomycetes gave 100% mortality. One of the Escherichia isolate suppressed the adult emergence completely while 27 others, belonging to most of the genera found, suppressed significantly. Isolates of Aspergillus, Alternaria and Streptomyces inhibited the emergence of adults completely.