Research Information System
FRESENIUS ENVIRONMENTAL BULLETIN, vol.27, no.1, pp.154-159, 2018 (SCI-Expanded)
Biolarvicides, based on crystal toxins of certain strains of Bacillus sphaericus are highly effective against mosquito larvae. The wide variety of formulations based on spore-crystal complexes intended for ingestion by target insects, are the result of many years of research. Depending on the formulation and environmental conditions, B. sphaericus is generally effective from 1-4 weeks after application. In this work we aimed to detect the extracellular proteases in mosquito breeding areas as the environmental factors that affect the life of the biolarvacide formulations. Thus, 120 bacterial isolates from some mosquito habitats in Turkey were obtained and screened for their putative proteolytic extracellular protease(s) against B. sphaericus strain 2362 mosquitocidal toxin. Two isolates, identified as B. cereus and B. thrungiensis according to 16s rDNA, have extra cellular proteases which have high activity against crystal toxin. The bioassay applications using the larvae of the Culex spp. were also performed. The results confirmed the efficacy of the aquatic bacteria on the B. sphaericus crystal toxin. The proteolytic activity of the bacteria isolated-from aquatic mosquito environments indicates that the microbial content of the mosquito habitats should be taken into account when bacterial insect controlling agents, like B. sphaericus formulated larvicide, are to be used.