Susceptibility of Larval Stage of Mosquito Culex Quenquifasciatus Say against Four Insecticides

Bioassay tests were carried out to investigate the susceptibility status of two (3rd and 4th) instar larvae of Culex quenquifasciatus Say populations of Dhaka city against two organophosphate (malathion and chloropyrifos) and two pyrithroid (cypermethrin and lambdacyhalothrin) insecticides. The LC50 values of malathion, chloropyrifos, cypermetrin and lambdacyhalothrin against the 3rd instar larvae were 0.33, 0.02, 0.007 and 0.003 ppm, respectively; and against the 4th instar larvae were 0.426, 0.028, 0.008 and 0.004 ppm, respectively. On the other hand, the LC90 values of the insecticides were 4.448, 0.079, 0.073, 0.014 ppm, respectively for the 3rd instar larvae and 6.032, 0.113, 0.067, 0.019 ppm, respectively for the 4th instar larvae. mvi-ms‡¶ct Bioassay cix¶vi gva ̈‡g PviwU KxUbvkK e ̈envi K‡i XvKv kn‡ii Culex quenquifasciatus Say gkvi Z...Zxq Ges PZz_© jvf©v `kvi susceptibility status Aby mÜvb Kiv n‡q†Q| Z...Zxq jvf©v `kvq malathion, chloropyrifos, cypermetrin and lambdacyhalothrin KxUbvk‡Ki LC50 gvb h_vμ‡g 0.33, 0.02, 0.007 Ges 0.003 wcwcGg; †hLv‡b PZz_© jvf©v `kvq gvb h_vμ‡g 0.426, 0.028, 0.008 Ges 0.004 wcwcGg| D‡j−L ̈, PviwU KxUbvkK e ̈envi K‡i Z...Zxq jvf©v `kvi Rb ̈ LC90 gvb cvIqv †M‡Q h_vμ‡g 4.448, 0.079, 0.073 Ges 0.014 wcwcGg; PZz_© jvf©v `kvq gvb h_vμ‡g 6.032, 0.113, 0.067 Ges 0.019 wcwcGg |