Resistance development and insecticide susceptibility in , an important vector of human diseases, against selection pressure of temephos and its relationship to cross-resistance towards organophosphates and pyrethroids insecticides.

BACKGROUND

is an important vector of human diseases.

OBJECTIVE

To determine the insecticide resistance development in against selection pressure of temephos..

METHODS

A field population of was collected from Northwestern Tunisia with a medium level of temephos resistance (LC = 0.0069). It was subjected to six generations of temephos pressure selection to evaluate its relationship to cross-resistance towards organophosphates (OPs) and pyrethroids (PYR) insecticides.

RESULTS

The selection was initiated at the dose 0.0266, 0.0748 and 0.0069 which were increased during successive generations up to 0.1488, 3.8747 and 0.0086 after sixth generation for temephos, chlorpyrifos and permethrin insecticides, respectively. It is important to noted that high cross-resistance to chlorpyrifos insecticide (OP) was detected (51.88×). However, little or no cross-resistance to the pyrethroid permethrin (PYR) was recorded (1.24×). Contrary to metabolic resistance, it seemed that acetylcholinesterases AChE 1 was fixed under pressure selection.

CONCLUSION

The high cross-resistance to temephos and chlorpyrifos is reasonable because they belong to the same class of insecticide (OP). However, the little cross-resistance to the pyrethroid permethrin could support its use alternately for control.