The blue stem borer, H. farinaria Turner has a bivoltine life cycle on ragwort, S. jacobaea L., in northern Tasmania. Development is continous, although the insect overwinters as a quiescent larva until the onset of warmer weather in spring. Adults are active from late Nov. and larvae from this generation quickly complete their development during summer. Second generation adults fly from mid-Feb. until March. Surveys showed that infestations in ragwort were more common in the north than in the south. Four hymenopterous parasites were identified during the study of which a braconid, Apantales sp., was predominant.