COMPARISON BETWEEN THE VARIATION OF DETOX IFYING CAPACITY AND THE DIFFERENT SUSCEPTIBILITY TO MALATHION ACCORDING TO THE AGE OF NYMPHS-V OFTRIATOMA-INFESTANS

The tolerance to the organophosphorus insecticide malathion in nimphs V of Triatoma infestans was notabily higher at the end of this larval stage. The possibility of this differential toxicity response dependen t on nimphs V age were due to changes in the detoxifying capacity medi ated by hydrolases or glutathione transferases. The experimental evide nces obtained would indicated that the malathion carboxyesterases woul d not be the primary cause of the differential toxicity but the glutat hione transferases and phosphorotriesterases could contribute to expla in this phenomenon.