Toxicity of leaves from the castor oil plant, Ricinus communis L. (Euphorbiaceae), to adult grass grub, Costelytra zealandica (White) (Coleoptera: Scarabaeidae)

Abstract

Abstract Adult grass grubs, Costelytra zealandica (White), die shortly after feeding on castor oil plant (Ricinus communis L.) leaves in the field. Chemical constituents of R. communis leaves were extracted and fractionated. A bioassay using grass grub adults confirmed that fresh R. communis leaves and some of the chemical fractions were toxic. The main toxic substance was identified by mass spectrometry as the alkaloid ricinine.