Various alkaloids from Adhatoda vasica (Acanthaceae) were found to be responsible for the antifertility and antifeedant activity of the extracts of the plant against insects. Among the major alkaloids vasicine, vasicinol and vasicinone severe antifertility effects were exhibited by vasicinol against Dysdercus skoenigii and Tribolium castaneum due to blocking of oocytes in the oviduct. Feeding deterrence was observed against Aulacophora foveicollis and Epilachna vijintioctopunctata at 0.05 and 0.1% levels of these compounds. These allelochemics appear to show a dual activity vis-à-vis a species specificity.
