The present study was conducted to evaluate the larvicidal and pupacidal efficacy of Spinosad on Culex species in their breeding habitats in village of Saft, Beni Suef Governorate, Egypt. The results showed that Spinosad caused a pronounced toxicity against C. pipiens. The total mortality of second and fourth larval instars was achieved by lower concentrations of Spinosad. While the highest pupal morality of C. pipiens was obtained by concentration of 5000 ppm (93.3%), after 168 h under laboratory conditions. Spinosad was applied with concentration of 5000 ppm at semi-field experiments and resulted total mortality of larval instars of C. pipiens, C. theileri and C. perexiguus after 24 and 48 h of exposure. The same concentration induced strong pupal mortalities of C. pipiens, C. theileri and C. perexiguus (90, 60 and 70%), respectively after 48 h. The field experiments, Spinosad (5000 ppm) induced total mortality of larval instars of Culex species and the pupal mortality was higher in breeding habitat, cement irrigation tank (77.8 %) and decreased to 36.4% in agriculture canal. The present study concluded that Spinosad is a promising larvicide that can be used in treatment of mosquito breeding habitat sites with low efficacy on pupae at some habitat sites such as agricultural canals.

Culex pipiens was the main vector of Bancroftian filariasis that causes filariasis disease in Egypt. Effect of chlorpyrifos on field strains of C. pipiens in laboratory and their field breeding habitats were evaluated in village of Saft, Beni Suef Governorate, Egypt. Under laboratory conditions, all tested concentrations (0.5-25 ppm) of chlorpyrifos caused complete mortality of the larval instars compared to the control treatment. While, the pupal mortality significantly increased with increasing concentrations of chlorpyrifos and the highest pupal morality of C. pipiens was obtained at 25 ppm. Under semi field trials, the highest morality in immature stages of C. pipiens was obtained at concentration of 25 ppm which were 100.0, 100.0 and 96.7% for second and fourth larval instars and pupal stage, respectively after 48 h. While in under field conditions, the complete reduction in density of immature stages of C. pipiens in treated cement tanks with chlorpyrifos was at 25 ppm after 24 h. The reduction in C. pipiens density was slightly lower in other breeding habitats (Agriculture canals and drains). In agricultural canals, the percentages of reduction in density of second and fourth instars and pupal stage were 95.3, 81.9 and 87.5%, respectively after 24 h, while in drains were 87.0, 70.9 and 50.0%, respectively. Our results were indicated that chlorpyrifos was effective on C. pipiens in most of their breeding habitats.