Effects of Azadirachtin on the Development and Mortality of Lutzomyia longipalpis Larvae (Diptera: Psychodidae: Phlebotominae)

Abstract

The effects of azadirachtin A added to the standard diet on the development, mortality, and metamorphosis of Lutzomyia longipalpis Lutz & Neiva, 1912 were studied. Concentrations of 0.1, 1.0, and 10.0 microg of azadirachtin/mg of diet significantly increased larval mortality in comparison with nontreated insects. Concentrations 0.1 and 1.0 microg blocked the molt of larvae, which remained as third instars until the end of the experiment. The 10 microg/mg concentration resulted in greater molt inhibition. In this group, all insects stopped their development as second instars. Simultaneous addition of ecdysone (1 microg/mg) to the standard diet containing azadirachtin counteracted the effects of azadirachtin on mortality and inhibition of ecdysis. These results indicate that azadirachtin is a potent growth inhibitor of L. longipalpis.