The Effects of Cypermethrin Pour-on and Piperonyl Butoxide on Triatoma infestans Under Laboratory Conditions

AMELOTTI I, CATALÁ S Y GORLA D.

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Columbia; Año: 2010 vol. 47 p. 1135 - 1140

0022-2585

The effect of exposing Triatoma infestans to chickens treated with cypermethrinpour-on combined with piperonyl butoxide (PBO) was studied. Four groups of treated chickens and one control group were used. Each treatment received 1 or 2ml of the cypermethrin formulation with and without PBO. Independent groups of nymphs were fed 1, 7, 15, 30, and 45 d after the treatment application. Blood intake was estimated after each feeding occasion. Up to 15 d after the pour-on application, high mortality was observed in allnymphsfed on treated chickens (>93%+/-12), and lower than the nymphs of the control group (<33% +/-15). After 30 d of the pour-on application, there was signiÞcantly different mortality between the treatment with 1 ml (80% +/- 9) and 2 ml (>96% +/-5); no difference was observed between groups with or without PBO addition. After 45 d of the pour-on application, the treatments did not show signiÞcant differences (77% +/- 7), although all treatments showed higher mortality than the control group (10% +/- 9). Up to 45 d after the pour-on application, blood intake by nymphs exposed to treated chickens (0.85 +/- 0.96 mg/nymph) was lower than bloodintake by nymphs exposed to control chickens (6.7 +/-5 mg/nymph). This study shows that cypermethrin pour-on produces high mortality and reduces the blood intake of third-instar nymphs of T. infestans up to 45 d after the insecticide application to chickens. PBO did not produce a detectable effect.