Effect of azadirachtin on Mesocyclops leuckarti sensu lato, vector of dracunculiasis.

Extension or otherwise of characteristic insect development inhibitory effects of the neem sesquiterpenoid azadirachtin have been examined on eggs and nauplii of the crustacean cyclops, M. leuckarti sensu lato, a major vector of guineaworm disease at 0.1 ppm and above doses. Azadirachtin reduced survival of early nauplii (N1 to N3) at 0.1 ppm and above doses. No such effect was observed when eggs and late nauplii (N4 to N5) were exposed. Azadirachtin did not affect the moult cycle when late nauplii (N4 to N5) were exposed continuously till adulthood. At all concentrations tested, adult cyclops exhibited normal mating.