[Resistance to organophosphorous and carbamates insecticides in a population of Culex quinquefasciatus].

The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil) has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively) to this insect population is reported. The results show the need to develop an insecticide management program. The susceptibility to permethrin (pyretroid) suggests the possibility of using this class of insecticide should the need for replacement of the insecticide in use arise.