High Insecticides Resistance in Culex pipiens (Diptera: Culicidae) from Tehran, Capital of Iran

<p><strong>Background:</strong> During recent years transmission of <em>Dirofilaria immitis </em>(dog heart worm) by <em>Culex pipiens</em> and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of <em>Cx. pipiens</em> collected from capital city of Tehran, Iran<strong>.<br />Methods:</strong> Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard methods were used for evaluating the susceptibility status of <em>Cx. pipiens</em> from Tehran moreover For comparison susceptibility status a Laboratory strain also was used. Bioassay data were ana­lyzed using Probit program. The lethal time for 50% and 90% mortality (LT₅₀ and LT₉₀) values were calculated from regression line.<strong><br />Results: </strong>The susceptibility status of lab strain of <em>Cx. pipiens</em> revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT₅₀=36 seconds and DDT with LT₅₀=3005 seconds had the least and most LT₅₀s. Field population was resistance to all tested insecticides and DDT yielded no mortality.<strong><br />Conclusion: </strong>Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control.