Current Susceptibility Status of Anopheles stephensi (Diptera: Culicidae) to Different Imagicides in a Malarious Area, Southeastern Iran

<p><strong>Background:</strong><strong> </strong><em>Anopheles</em> mosquitoes are an important group of arthropods due to their role in transmission of ma­laria. The present study was conducted for determination of susceptibility status of <em>Anopheles stephensi </em>to different imagicides<em> </em>collected from malarious area in Chabahar city, Iran.<strong><br />Methods: </strong>In the present study seven insecticides including: DDT 4%, lambdacyhalothrin 0.05%, deltamethrin 0.05%, permethrin 0.75%, cyfluthrin 0.15% and etofenprox 0.5% were tested based on WHO method. Regression line was plotted for each insecticide using mortality of different exposure times. Bioassay data were analyzed using Probit software and the lethal time for 50% and 90% mortality (LT₅₀ and LT₉₀) values were calculated.<strong><br />Results:</strong> The susceptibility levels of field strain of <em>An. stephensi </em>to the discriminative dose of different imagicides were determined 100, 98, 96, 89, 82 and 62% for etofenprox, permethrin, deltamethrin, lambdacyhalothrin, cyfluth­rin and DDT, respectively. Our finding indicated that <em>An. stephensi </em>is resistant to<em> </em>DDT, lambdacyhalothrin and cyfluthrin, and susceptible to etofenprox and permethrin and candidate of resistant to deltamethrin based on WHO criteria.<strong><br />Conclusion: </strong>Our findings indicated that <em>An. stephensi</em> is resistant to DDT and some pyrethroid insecticides which can be developed due to application of insecticides in health and agriculture. These results can provide a clue for future chemical control program in the study area.