Delairea odorata Lemaire (Cape ivy) (Asteraceae) has become naturalized and invasive in many countries including the United States of America where biological control is being considered as a long-term solution to managing this invasive vine. Extensive surveys throughout the natural range of D. odorata in South Africa revealed a large arthropod fauna associated with the plant. Amongst the herbivorous insects showing potential as possible biological control candidates was Diota rostrata (Wallengren) (Noctuidae: Arctiinae), a widespread defoliating moth. Although D. rostrata is highly fecund with a short life cycle, laboratory host range tests indicated that the moth had a wide host range that included other Senecio spp. with soft or fleshy leaves. Although all further testing was terminated, the study contributes towards a better understanding of the biology and host preferences of D. rostrata.