Potencial dos reguladores de crescimento de insetos (IGRs) Diflubenzuron e Methoprene, no controle de Aedes aegypti (L.) (Diptera: Culicidae) em Uberlândia - MG

Abstract

Aedes aegypti (L.), the vector of urban yellow fever and dengue, is controlled in Brazil mainly by the use of the organophosphate Temephos. Resistance to Temephos has been described in Brazil and in other countries as well. Insect Growth Regulators (IGRs), Diflubenzuron (chitin synthesis inhibitor) and Methoprene (juvenile hormone analog), are insecticides that affect the development of insects by affecting adult emergence. A. aegypti susceptibility to Diflubenzuron and Methoprene was investigated in Uberlândia, by studying the 50% and 95% lethal concentrations of both IGRs for the A. aegypti population (LC50 and LC95) and their action on the immature stages. In addition, other aspects, such as IGRs residual activity and the effect of sublethal dosages upon adult symmetry, size, weight, fecundity, fertility and longevity were investigated. The experiments were done in laboratory conditions using individuals from a colony originated from eggs collected in the urban area of Uberlândia. The number of replicates was six in all assays. The confidence level adopted in all the statistical analysis was 95%. The LC50 and LC95 of Diflubenzuron and Methoprene were 5.19 and 12.24 ppb; 19.95 and 72.08 ppb, respectively. Diflubenzuron was effective in all larvae instars and Methoprene caused greater mortality when the mosquito was exposed from the early fourth instar larvae on. Concentrations of commercial IGRs presented greater residual activity than did the technical formulations. Increased levels of fluctuating asymmetry were observed in the mosquitoes exposed to Diflubenzuron. Females treated with Methoprene showed smaller weight than did the untreated females. On the other hand, the longevity of the mosquito was reduced in the groups treated with both IGRs. The LC50 and LC95 of Diflubenzuron obtained here are compatible with the values observed for this IGR in other studies, while the LCs of Methoprene were higher than those generally reported in the literature. However, the results obtained here indicate that Diflubenzuron and Methoprene are potential tools to control this mosquito in the region of Uberlândia.