Incoordination, paralysis and recovery after pyrethroid treatment on nymphs III of Triatoma infestans (Hemiptera: Reduviidae).

Symptoms of poisoning for deltamethrin and cis-permethrin on nymphs III of Triatoma infestans were described. The time required for incoordination and paralysis were determined. Deltamethrin was equal or more rapid in the onset of the first effect (accordingly to dose), and cis-permethrin in the onset of the second one. There were no significant differences between incoordination doses 50% (IncD50s) at different times for the two pyrethroids. They showed equivalent incoordination power, but the nymphs treated with deltamethrin recovered slightly more rapid and in greater amount than the nymphs treated with cis-permethrin. The recovery was inhibited by the simultaneous application of piperonyl butoxide. This result suggests that biotransformation by mixed-function microsomal oxidases are involved in the process of recovery.