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Bacillus sphaericus mosquito pathogens in the aquatic environment

Abstract

The fate of Bacillus sphaericus spores in the aquatic environment was investigated by suspending spores in dialysis bags in fresh and seawater. Spore viability was lost more rapidly in seawater. Neither B. sphaericus nor B. thuringiensis israelensis (B.t.i.) spores mixed with pond sediment appeared to attach to the sediment. However, rapid decrease in B.t.i. toxicity suggested attachment of parasporal bodies to sediment. B. sphaericus toxin settled more slowly and less completely. B. sphaericus spores fed to larvae of four aquatic invertebrates were mostly eliminated from the animal gut in less than one week. An exception was the cranefly (Tipula abdominalis) where spores persisted in the posterior gut for up to five weeks.

Bacillus sphaericus; Bacillus thuringiensis israelensis; mosquito pathogenic bacteria; bacterial spores; Chironomus riparius; Paragnetina media; Pteronarcys proteus; Tipula abdominalis; biological control


ABSTRACT

Bacillus sphaericus mosquito pathogens in the aquatic environment

Allan A Yousten1

Ernest F Benfield1

Fred J Genthner2

Virginia Polytechnic Institute and State University, Biology Department, Blacksburg, USA

U. S. Environmental Protection Agency, Microbial Ecology and Biotechnology Branch, Environmental Research Laboratory, Gulf Breeze, USA

The fate of Bacillus sphaericus spores in the aquatic environment was investigated by suspending spores in dialysis bags in fresh and seawater. Spore viability was lost more rapidly in seawater. Neither B. sphaericus nor B. thuringiensis israelensis (B.t.i.) spores mixed with pond sediment appeared to attach to the sediment. However, rapid decrease in B.t.i. toxicity suggested attachment of parasporal bodies to sediment. B. sphaericus toxin settled more slowly and less completely. B. sphaericus spores fed to larvae of four aquatic invertebrates were mostly eliminated from the animal gut in less than one week. An exception was the cranefly (Tipula abdominalis) where spores persisted in the posterior gut for up to five weeks.

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Publication Dates

  • Publication in this collection
    26 May 2009
  • Date of issue
    Feb 1995
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