Investigation on azadirachtin against Culex pipiens pallens

Objective To investigate the effectiveness of azadirachtin against Culex pipiens pallens. Methods Dipping methods were used.The growth and development of Culex pipiens pallens exposured to azadirachtin with various concentrations were observed such as toxicity,growth-regulating activity,blood-feeding,reproduction and the longevity. Results The young larvae were more sensitive to azadirachtin than older larvae,and the value of LC50 decreaesd with a longer post treated-time.Azadirachtin showed growth inhibiting effect on larvae,and the effectiveness inserased with higher concentrations. Conclusion The rate of blood-feeding,eggs laid by per female,hatchability and the longevity of Culex pipiens pallens treated with azadirachtin were significantly different from the control group,but the toxicity to egg raft only showed within 4 h after laid.