Temperature effect on the insecticidal activity of pyrethroids on Triatoma infestans.

1. The toxic effect of deltamethrin, asymmethrin, alphamethrin, cypermethrin and cypermethrin High cis in nymphs III of Triatoma infestans was lower at 28 than 16 degrees C. 2. Prostration in treated nymphs III occurred more rapidly at 28 than 16 degrees C. 3. Symptoms of poisoning rapidly disappeared when nymphs III intoxicated were moved from 16 to 28 degrees C. 4. Nymphs III exposed to low doses of pyrethroids at 28 degrees C, which did not show symptoms of poisoning, were rapidly affected when they were moved to 16 degrees C.