Effectiveness of methoprene, an insect growth regulator, against temephos-resistant Aedes aegypti populations from different Brazilian localities, under laboratory conditions.
The susceptibility of Aedes aegypti (L.) larvae from several Brazilian populations to the juvenile hormone analog methoprene and the organophosphate insecticide temephos were investigated. Populations from Natal (northeastern region), Macapá (northern region), and Jardim América, Rio de Janeiro (southeastern region) are temephos-resistant (RR90 = 24.4, 13.3, and 15.8, respectively), whereas populations from Presidente Prudente (southeastern region) and Porto Velho (northern region) exhibit only an incipient temephos-altered susceptibility status (RR90 = 1.8 and 2.6, respectively). Biochemical assays revealed alterations of the enzymes implicated in metabolic resistance, glutathione S-transferase, mixed function oxidases and esterases, among these populations. Dose-response assays showed at most a low resistance to methoprene of all populations tested, irrespective of their temephos resistance level. However, sequential exposure of Macapá and Natal populations to temephos and methoprene indicated a potential cross-resistance when larvae are exposed to both insecticides. Nevertheless, susceptibility of the Brazilian Ae. aegypti populations to methoprene alone suggests this insect growth regulator could substitute for temephos in the control of the dengue vector in the country.
Braga
Ima Aparecida
IA
Departamento de Entomologia, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, CEP 21045-900, Brazil.
Mello
Cícero Brasileiro
CB
Montella
Isabela Reis
IR
Lima
José Bento Pereira
JB
Martins
Ademir de Juses Júnior
Ade J
Medeiros
Priscila Fernandes Viana
PF
Valle
Denise
D
D000110:Acetylcholinesterase / Q000378:metabolism; D000330:Aedes / Q000187:drug effects* / Q000254:growth & development*; D000818:Animals; D001938:Brazil; D004305:Dose-Response Relationship, Drug; D005982:Glutathione Transferase / Q000378:metabolism; D007300:Insect Control / Q000379:methods*; D007306:Insecticides / Q000633:toxicity*; D008726:Methoprene / Q000633:toxicity*; D000002:Temefos / Q000633:toxicity*
D007306:Insecticides; D008726:Methoprene; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D000002:Temefos