Susceptibility to temephos,permethrin and deltamethrin of Aedes aegypti(Diptera:Culicidae) from Muang district,Phitsanulok Province,Thailand

Objective:To investigate the susceptibility to temephos.permethrin and deltamethrin of Aedes aegypti Ae.aegypti),collected from areas with high incidence of dengue hemorrhagic fever cases in Phitsanulok Province.Thailand.Methods:The F1 progenies of Ae.aegypti colony,originated from five sub-districts including Aranyik.Hua Ro,Nai Muang.Ban Krang and Tha Pho,were used in the bioassays following the procedures of World Heath Organization.For larval bioassay.the late third or early fourth-instar lanae were tested with different concentrations of temephos.For adult bioassay.the females were exposed to 0.75%permethrin or 0.05%deltamethrin.LC;value and mortality rate were analyzed to compare the insecticide susceptibility of the larvae and the adults in each area,respectively.Results:The LC;value of temephos for the larvae from Aranyik.Hua Ro.Nai Muang,Ban Krang and Tha Pho sub-districts was 0.017.0.017.0.026.0.061.and 0.113 ppm,respectively.For permethrin,the highest morlalitv rate（86.84%） was found in the mosquitoes from Aranyik but the others were more resistant with the lower morlality rates（16.00-42.67%）.The adult morlality rates after exposing to dellaiiielhrin were higher（82.34-98.67%） in all areas.Conclusions:Ae.acgypti larvae were still susceptible to temephos.Conversely,most tested adults tended to resist the penmethrin and deltamethrin.