Abstract Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides) and adults (adulticides) create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV), was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV) was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90) were age-dependent, with early instars requiring a lower concentration com- pared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV) than was Aedes aegypti. Fecundity rate was highly reduced after treatment with differ- ent concentrations of Bacillus sphaericus (Bs G3-IV). Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV), total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV) to be an effective mosquito control agent that can be used for more integrated pest management programs. Introduction Mosquitoes are insect vectors responsible for the transmission of many diseases. Mosquito-borne diseases include yellow fever, dengue fever and Chikungunya, transmitted mostly by Aedes aegypti; malaria, carried by the genus Anopheles, and Culex serves as a vector of impor- tant diseases such as West Nile virus, filariasis, Japanese encephalitis, St. Louis encephalitis, and avian malaria. Insect-transmitted disease remains a major source of illness and death worldwide. Mosquitoes alone transmit disease to more than 700 million people annually and are responsible for several million deaths every year (WHO, 2012; Taubes, 2000; Kessler & Guerin, 2008). Management of these vectors is a serious concern in a developing country like India, due to development of pesticide resistance and for socio-economic reasons. Every year, a large part of the population is affected by one or more vector-borne diseases. Vector control, which includes both anti-larval and anti-adult measures, constitutes an impor- tant aspect of any mosquito control program. Mosquito control using synthetic insecticides is an effective vector control strategy used exten- sively in daily life. Synthetic insecticides are still at the forefront of mos- quito-controlling efforts. However, the environmental threat that these chemicals pose affects on non-target organisms, and resistance of mos- quitoes to insecticides have all increased during the last five decades (Wattanachai & Tintanon, 1999; Amer & Mehlhorn, 2006a, 2006b). In recognition of these facts, it is necessary to develop new insecti- cides for controlling mosquitoes that are environmentally safer, biodegradable, and more target-specific against the mosquitoes. Recent negative consumer perceptions concerning the use of chemi- cals as larvicides have shifted research efforts towards the develop- ment of alternatives that the public perceives as natural products, such as bacterial pesticides, predators, and plant extracts. Consequently, the present work deals with the insecticidal activities of natural products, such as bacterial pesticides. Bacillus sphaericus is an aerobic, mesophilic, spore-forming bac- terium with terminal swollen sporangia and spherical spores. As a con- sequence of the specific toxicity to mosquito larvae of binary toxin (Bin) and mosquitocidal toxins (Mtxs) produced during the sporula- tion and vegetative stages, respectively, some toxic strains have been widely used for many years as biopesticides in the field in mosquito control programs (Bei et al., 2007). Bacillus sphaericus is a naturally occurring soil bacterium that can Journal of Entomological and Acarological Research 2012; volume 44:e15 Correspondence: Kadarkarai Murugan, Department of Zoology, Bharathiar University, Coimbatore, 641046, India. E-mail: kmvvkg@gmail.com Key words: Bacillus sphaericus (Bs G3-IV), Aedes aegypti, Culex quinquefas- ciatus, fecundity, mosquito longevity. Acknowledgments: we are very thankful to the authorities of the Defence Research and Development Laboratory (DRDL), Defence Research and Development Organization, Ministry of Defence, Government of India, Tezpur for providing funds plus their isolate of Bacillus sphaericus, for the successful completion of this project. Received for publication: 20 August 2012. Revision received: 20 November 2012. Accepted for publication: 20 November 2012. ©Copyright A. Nareshkumar et al., 2012 Licensee PAGEPress, Italy Journal of Entomological and Acarological Research 2012; 44:e15 doi:10.4081/jear.2012.e15 This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (by-nc 3.0) which permits any noncom- mercial use, distribution, and reproduction in any medium, provided the orig- inal author(s) and source are credited. Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV) on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus A. Nareshkumar, 1 K. Murugan, 1 I. Baruah, 2 P. Madhiyazhagan, 1 T. Nataraj 1 1 Department of Zoology, Bharathiar University, Coimbatore; 2 Defence Research and Development Organization, Defence Research Laboratory, Assam, India [Journal of Entomological and Acarological Research 2012; 44:e15] [page 79] Non-commercial use only