Abstract

Study Confirming Resistance to Fenitrothion of Culex pipiens (Diptera: Culicidae) from Central Tunisia

Ahmed Tabbabi, Jaber Daaboub, Ali Laamari, Raja Ben Cheikh, Ibtissem Ben Jha and Hassen Ben Cheikh

Five natural populations of Culex pipiens were taken as larvae in the central Tunisia to evaluate their resistance level of fenitrothion. Our study showed that all samples were resistant to fenitrothion at LC50. The RR50 ranged from 9.2 in sample # 2 to 59.2 in sample # 5. Starch electrophoresis detected the overproduced esterases in all studied samples. The most frequent esterase A2B2 was detected in samples # 5 with a frequency of 31%. Three other esterases were detected in samples # 1, 2, 3, and 4: A4-B4 and/or A5-B5, A12, and C1. Synergists showed that the involvement of CYTP450 in the resistance to fenitrothion (OP) is not neglected. Cross-resistance of fenitrothion and propoxur was detected indicate the involvement of target site alteration (AChE1) in fenitrothion resistance. It should be noted that study of the polymorphism of AChE 1 will be of great importance.