Resistance status to deltamethrin pyrethroid of Culex pipiens pipiens (Diptera: Culicidae) collected from three districts of Tunisia

OBJECTIVES: populations against deltamehtrin insecticide. METHODS: were collected from three breeding places in Northern and Southern Tunisia between 2003 and 2005. Early third and late fourth instars were tested against deltamethrin pyrethroid insecticide. Cross-resistance with DDT resistance was evaluated in studied samples to estimate the role of target site insensitivity and two synergists including piperonyl butoxide (Pb) and S,S,S-tributyl phosphorotrithioate (DEF) were used to estimate the role of detoxification enzymes. RESULTS: Our results revealed that the level of deltamehtrin resistance ranged from 0.67 to 31.4. We also showed the non-involvement of kdr resistance in pyrethroid resistance and no cross-resistance with DDT resistance was detected in all studied populations including the most resistant one. Synergists study on the resistant population (sample # 1) showed the involvement of CYP450 in the recorded resistance to the deltamethrin insecticide. CONCLUSION: The results obtained from this study should be considered in the current control programs to combat mosquitoes in Tunisia.