Temephos Resistance and Esterase Activity in Selected Laboratory Population of Culex Pipiens from Tunisia

Selection for resistance to temephos (an organophosphorus insecticide) was performed by exposing larvae of the field-collection population of Culex pipiens to increasing doses of temephos for four generations. Mosquito larval specimens were captured in Northwestern Tunisia and identified using morphological keys. Two insecticides including temephos and propoxur were used evaluating the susceptibility status of the selected population. Bioassays results showed high resistance to temephos and no esterase activity. A new esterase was first detected in one sample among 60 tested. This result will help to elucidate resistance mechanisms, which is essential for the planning of future insecticide resistance management programs.