Synergism between cis-permethrin and benzoyl phenyl urea insect growth regulators against Aedes aegypti larvae.
Emulsifiable concentrate formulations of 2 insect growth regulator (IGR) benzoyl ureas (novaluron and diflubenzuron) and the pyrethroid cis-permethrin were individually bioassayed against late 3rd- or early 4th-stage larvae of susceptible Aedes aegypti. The emergence inhibition 50% were 0.038, 0.048, and 0.179 ppb for novaluron, diflubenzuron, and cis-permethrin, respectively. We also tested 1:1 (v:v) mixtures of cis-permethrin and benzoyl ureas. Emergence inhibition 50% for novaluron plus cis-permethrin and diflubenzuron plus cis-permethrin were 0.030 and 0.037, respectively, with combination indexes of 0.49 and 0.56, indicating a synergistic interaction between these insecticides. The percentage of larval mortality produced by 0.5 ppb of the mixtures of cis-permethrin and each IGR was compared to the addition of larval mortality produced in separated experiments by 0.25 ppb of each component, after 5, 9 and 13 days of continuous exposure. In all bioassays, the novaluron plus cis-permethrin mixture produced a significantly higher larvicidal effect (P < 0.05) compared with the individual contribution of each compound. The diflubenzuron plus cis-permethrin mixture showed significantly higher larval mortality (P < 0.05) compared with the contributive effect of each insecticide after 9 and 13 days of exposure, but there was no significant difference after 5 days of exposure.
Sfara
Valeria
V
Centro de Investigaciones de Plagas e Insecticidas (CIPEIN) CITEFA-CONICET, Juan Bautista de La Salle 4397, Villa Martelli, Provincia de Buenos Aires (B1603ALO), Argentina.
De Licastro
Susana A
SA
Masuh
Hector M
HM
Seccacini
Emilia A
EA
Alzogaray
Raul A
RA
Zerba
Eduardo N
EN
D000330:Aedes; D000818:Animals; D004357:Drug Synergism; D007306:Insecticides / Q000494:pharmacology*; D007605:Juvenile Hormones / Q000494:pharmacology*; D007814:Larva; D026023:Permethrin / Q000494:pharmacology*; D010671:Phenylurea Compounds
D007306:Insecticides; D007605:Juvenile Hormones; D010671:Phenylurea Compounds; D026023:Permethrin