INDIGENOUS-PLANT EXTRACTS AS LARVICIDAL AGENTS AGAINST CULEX-QUINQUEFASCIATUS SAY

Bioassay studies of the laboratory-colonised larvae (LCL) and field-co llected larvae (FCL) of Culex quinquefasciatus with Jive different con centrations of 12 different plant extracts (petroleum ether solvent) s howed that the extracts of Argemone mexicana, Jatropha curcus, Pergula ria extensa and Withania somnifera had acute toxicity. The benzene ext racts of these four plants were tested for their toxic effects on LCL and FCL. Argemone mexicana showed acute toxicity and observations made at 31.25 ppm concentration showed larval and pupal mortality; larval- pupal intermediates; half ecdysed organisms and prolonged larval and p upal duration. (C) 1997 Elsevier Science Ltd.