13 Comparative efficacy of pyrethroids against several strains of Asian Culex quinquefasciatus

Susceptibility of several strains of Asian Culex quinquefasciatus (Indonesia, Thailand, Vietnam and Malaysia strain) to several pyrethroids and an organophosphate was investigated. Metofluthrin, a newly synthesized pyrethroid, was most effective against four strains of C. quinquefasciatus. The relative effective ratio of metofluthrin against transfluthrin seemed to be larger in C. quinquefasciatus than in C. pipiens pallens. Vietnam strain was most susceptible among the strains in the study. The combinational use of metofluthrin with the other controlling methods for tropical diseases will be effective and further studies concerning the effective formulation and the efficacy against the other insects of medical importance will be needed.