Lethal amounts of ricinine in green peach aphids (Myzus persicae) (Suzler) fed on castor bean plants

The green peach aphid Myzus persicae (Sulzer) when fed on leaves of the castor bean plant Ricinus communis L. died 8 to 24 h later. Extraction and subsequent thin layer chromatographic (TLC) and high-performance liquid chromatographic (HPLC) analyses separated and showed the presence of ricinine in aphids fed on castor bean plants but not in aphids fed on leaves of Phaseolus vulgaris L. The results indicate that plant allelochemicals, which may be present in the phloem, play a role in plant defence mechanisms against aphids.