title: Insecticide susceptibility of field-collected populations of Culex tritaeniorhynchus in the Republic of Korea.
abstract: The toxicities of 10 insecticides were examined against late third instar Culex tritaeniorhynchus Giles (Diptera: Culicidae) using the direct-contact mortality bioassay. Six geospatially-distant field mosquitoes were collected from Chuncheon-si, Hwaseong, Seosan. Jeonju, Daegu, and Busan in the Republic of Korea. Marked regional variations of insecticide susceptibility were observed. Field populations of Seosan, Jeonju, and Daegu from agricultural areas showed higher to extremely higher insecticide susceptibility to pyrethroids than those of Chuncheon-si, Hwaseong, and Busan strains from non-agricultural areas. Extremely high to low levels of susceptibility were measured: bifenthrin, susceptible ratio (SR) = 2.7-896.3; β-cyfluthrin, SR = 1.8-633.3; α-cypermethrin, SR = 1.2-1,051.9; deltamethrin, SR = 1.3-711.1; permethrin, SR = 1.5-1,053.4; etofenprox, SR = 2.2-29.3; chlorfenapyr, SR = 5.1-103.6; chlorpyrifos, SR = 2.3- 337.0; fenitrothion, SR = 2.0-142.3; and fenthion, SR = 1.4-186.2. Cx. tritaeniorhynchus populations from rice paddies had been under heavy selection pressure due to the agricultural insecticides, and that's why the mosquito species demonstrated high resistance to pyrethroids, which were used for a long time to control agricultural pests in the localities. These results indicate that careful selection and rotational use of these insecticides may result in continued satisfactory control against field populations of Japanese encephalitis vector mosquitoes.
authors.affiliation: Division of Medical Entomology, National Institute of Health, Chungcheongbuk-do 363-951, Republic of Korea.
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Yoo
authors.forename: E-Hyun
authors.initials: EH
authors.lastname: Shin
authors.forename: Dong-Kyu
authors.initials: DK
authors.lastname: Lee
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Ahn
authors.forename: Kyu-Sik
authors.initials: KS
authors.lastname: Chang
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Kim
authors.forename: Seong-Yoon
authors.initials: SY
authors.lastname: Kim
authors.forename: Chan
authors.initials: C
authors.lastname: Park
mesh_terms: D000818:Animals; D003465:Culex; D007305:Insecticide Resistance; D007306:Insecticides; D007814:Larva; D056910:Republic of Korea
chemical_list: D007306:Insecticides