Lethal effect of Streptomyces citreofluorescens against larvae of malaria,filaria and dengue vectors

<正>Objective:To investigate lethal effect of culture filtrates of Streptomyces citreofluorescens （S.citreofluorescens） against Anopheles stephensi（An.stephensi）,Culex quinquefasciatus（Cx. quinquefasciatus）,and Aedes aegypti（Ae.aegypti） larvae vectors for malaria,filarial and dengue. Methods:The culture filtrates obtained from S.cilreofluorescens 2528 was grown in Potato Dextrose Broth（PDB）,filtrated and used for the bioassay after a growth of 15 days.Results:The results demonstrated that the An.stephensi shows mortalities with LC50,LG40 values of first instar 46.8μL/mL,79.5μL/mL,second instar 79.0μL/mL,95.6μL/mL,third instar 79.0μL/mL,136.9μL/mL,and fourth instar 122.6μL/mL,174.5μL/mL Whereas,The Cx.quinquefasciatus were found effective on first instar 40.0μL/mL,138.03μL/mL,second instar 80.0μL/ml,181.97μL/ mL,third instar 100.0μL/mL,309.2μL/mL,and fourth instar 60.0μL/ml,169.82μL/mL.The Ae.aegypti were successfully achieved susceptible with higher concentrations in comparisons of An.stephensi and Cx.quinquefasciatus larvae.These outcomes of the investigations have compared with the Chitinase of Streptomyces griseus（S.griseus） C6137 that shows 90%-95% mortality.Conclusions:These new findings significantly permitted that the culture filtrates of S. citreofluorescens can be used as bacterial larvicides.This is an environmentally safe approach to control the vectors of malaria,dengue and filariasis of tropical areas.