Determination of insecticides diagnostic doses in susceptible Culex quinquefasciatus (Diptera: Culicidae)

Despite Mass Drug Administration cases of Lymphatic filariasis still exist in several developing countries such as, China, India, Indonesia, Malaysia and several Southeast Asian countries. Culex quinquefasciatus is the major vector that is dominant and widespread mosquito distributed in rural and urban areas. This study aimed at determining the diagnostic doses of LC50 and LC90 (lethal concentrations that causes 50% and 90% mortality respectively) of commonly used insecticides in Malaysia for dengue vector control by Malaysian Ministry of Health. The diagnostic LC50 of the Malathion, Pirimiphos methyl, Temephos and Deltamethrin insecticides were determined at 0.019mg/L, 0.0060 mg/L, 0.0011 mg/L and 0.0032 mg/L as well as LC90 0.033 mg/L, 0.012 mg/L, 0.0033 mg/L and 0.0010 mg/ml respectively. It is concluded that various LC50 and LC90 diagnostic doses of these insecticides were effective against the susceptible population of Cx. quinquefasciatus that also carries infective third instar larvae (L3) microfilariae. We recommend the use of these doses for effective control of Cx. quinquefasciatus population and constant monitoring of its susceptibility status will provide more information on the possible resistance that may affect the effort in the elimination of Lymphatic filariasis in affected countries.