The genetic variability of populations of Aedes (Stegomyia) aegypti (Linnaeus, 1762) is often low due to the intense selection pressure caused by chemical control measures. In this study, we evaluated the susceptibility of larvae and adults of this mosquito to chemical insecticides, the frequency of the Val1016IIe mutation, and the genetic variability of the mitochondrial ND4 gene fragment in the urban area of Foz do Iguaçu, Paraná. The populations of A. aegypti in the southern and central regions of the city were resistant to the diagnostic dose of temephos 0.0162 ppm. Additionally, we detected difference in susceptibility in the northern population. The resistance ratios (RR95) were 3.8, 4.1, and 4.6 for the populations in the north, central, and south of the city, respectively. The entire population of A. aegypti in Foz do Iguaçu is resistant to pyrethroids. The mortality rates are as follows: 72.2% for cypermethrin (CD: 146 mg i.a./m²) and 57% for deltamethrin (CD: 18 mg i.a./m²). These results corroborate the hypothesis that the mutated 1016Ile allele is present in all analyzed strata. Out of the 234 samples genotyped for the Val1016Ile mutation, 15% were homozygous dominant for the wild allele (Val/Val), 62% were heterozygous (Va/Ile) and 23% were homozygous for the recessive mutation (Ile/Ile). With respect to the genetic variability of the mitochondrial ND4 gene fragment, 93% of the sequences analyzed belonged to haplotype 1, and 7% belonged to haplotype 2. The genetic diversity was low, the fixation index was not significant, and gene flow was high. The control of A. aegypti in Foz do Iguaçu using temephos and pyrethroids may be compromised because of the reduced vector susceptibility. Populations of A. aegypti, that undergoes a sudden reduction in effective population size and become resistant to pyrethroids may differ from the original population in vector capacity.

Se evalúan productos de origen vegetal en busca de sustancias bioactivas que tengan la capacidad de reducir la dependencia de insecticidas organofosforados y piretroides, a los que las poblaciones de insectos se han vuelto resistentes. Por esta razón el objetivo de este estudio fue evaluar si los aceites esenciales de Guatteria hispida, G. blepharophylla y G. friesiana presentan efecto insecticida contra A. aegypti bajo condiciones de laboratorio. Los aceites esenciales se extrajeron a través de hidrodestilación por medio de un aparato tipo Clevenger, analizados por Cromatografía Gaseosa acoplada a Espectrometría de Masas (CG-EM) y Resonancia Magnética Nuclear (RMN). Los bioensa-yos se analizaron de acuerdo con el modelo Probit. Los análisis de (CG-EM) y (RMN) confrmaron que las hojas de G. blepharophylla presentan óxido de cariofileno como el principal componente; en G. friesiana fue a-, b- y g-eudesmol, y en G. hispida a- y b-pineno y (E)-cariofileno fueron los compuestos predominantes. La concentraciones letales CL50, CL95 y CL99 fueron respectivamente 85,74, 199,35 y 282,76ppm para G. hispida; 58.72, 107.6 y 138.37 ppm para G. blepharophylla; 52,6, 94,37 y 120,22ppm para G. friesiana. El aceite extraído de G. friesiana presentó el mejor efecto insecticida.

the products of vegetal origin were assessed for bioactive substances to reduce reliance on organophosphate and pyrethroid insecticides, to which insect populations have become resistant. For this reason the aim of this study was to assess whether the essential oils of Guatteria hispida, G. blepharophylla and G. friesiana have insecticidal effect against A. aegypti under laboratory conditions. Essential oils were extracted through hydrodistillation using a modifed Clevenger apparatus and analyzed by Gas Chromatography (CG-FID), Gas Chromatography coupled to Mass Spec-trometry (GC-MS), and Nuclear Magnetic Resonance (NMR). the bioassays were analyzed according to the Probit model. The GC-MS and NMR analyses confrmed that the leaves of G. blepharophylla have the caryophyllene oxide as their main component; in G. friesiana the a-,b- and g-eudesmols prevail, and in G. hispida a- and b-pinene, and (E)-caryophyllene are the predominant compounds. the lethal concentrations LC50, LC95 and LC99, were respectively 85.74, 199.35 and 282.76ppm for G. hispida; 58.72, 107.6 and 138.37ppm for G. blepharophylla; and 52.6, 94.37 and 120.22ppm for G. friesiana. the oil extracted from G. friesiana presented the best insecticidal effect.