AN ENHANCED TOLERANCE TO PERMETHRIN IN ANOPHELES STEPHENSI WITH PERMETHRIN AND OTHERENZYME INDUCERS

Pretreatment of adults of IRAQ strain of AfhStephenSt with a sub-letlial dose of pcrmethrin resulted in a 65% enliancemenl of tolerance to this insecticide. Similarly, pre-exposure of DUB-LPR larvae to a sub-lethal dose of pcrmethrin resulted in increased tolerance to pcrmethrin. For the sensitive IND-S strain, the inductive effect was smaller. Tiie results of bioassays of resistant and susceptible AtX.StCphensi females following pretreatment with sodium phenobarbital and subsequent exposure to pcrmethrin indicated that sodium phenobarbital increases the tolerance level of the IND-S strain to a greater extent titan the DVB-APR strain. Tliere was some evidence of enhancement of pcrmethrin tolerance in larvae of DUB-LPR and IND-S strains when they were treated with sodium phenobarbitaL Larvae of DUB-LPR and IND-S strains pretreated with mentlwl-related compounds exJiibited a significantly enlutnced tolerance to pcrmethrin. Treatment with a mentfwl - related compound induced a significant level of enhanced tolerance, as high as 3-fold in the case of larvae exposed to breeding water containing peppermint leaves in which menthol is probably the main active compound.