Efficacy of certain conventional and non-conventional insecticides against a vector of dengue fever, the Aedes aegypti Mosquito in Saudi Arabia

Dengue fever (DF) was originally discovered and registered in the Kingdom of Saudi Arabia within the premises of the Jeddah governate (province) during 1994. Currently there is no vaccine against this type of dengue virus, however, the most practical methods of suppression and control of this fatal disease are confined to the control of its vector. This study aimed to investigate the effectiveness of six types of conventional pesticides of the pyrethroid (Icon 2.5% and Residex C-10EC), organophosphorous (Rizfin 50% EC and Keen 600EC) and biocide (Bacilod and VectoMax) groups against the Aedes aegypti mosquito, as well as four pesticides in the insect growth regulators (IGR) groups (In 2 Mix and Starycide) and the plant oils group (lemon oil and peppermint oil). Taking the LC50 values (the concentration required for killing 50% of the individuals) into consideration, larvae of Ae. aegypti mosquitoes exhibited more susceptibility to Icon 2.5% (0.023 ppm) than Rizfin (0.032 ppm), Residex C-10EC (0.05 ppm), Keen (0.052 ppm), VectoMax FG (0.115 ppm) and Bacilod (0.174 ppm) by approximately 1.39, 2.18, 2.26, 5.1 and 7.6 fold, respectively. Based on the IC50 values (the concentration that prevents the emergence of 50% of adults), the IGR In 2 Mix (IC50 = 0.0023 ppm) revealed more larvicidal activity against Ae. aegypti than did Starycide 480 SC (0.0047 ppm), lemon oil (11.842 ppm) and peppermint oil (17.213 ppm) by approximately 2.04, 5.15 and 7.5 fold, respectively. The differences in susceptibility levels can be attributed to the mode of action and the nature of the active ingredients of each pesticide. Generally, these bioassay tests are of great importance to provide reference for mosquito control managers and make informed decisions on the best usage of insecticides.