The insect fauna of Chondrilla juncea L. (Asteraceae) in Bulgaria and preliminary studies of Schinia cognata (L.) (Lepidoptera: Noctuidae) as a potential biological control agent

摘要

Between 2001 and 2005, a survey of rush skeletonweed, Chondrilla juncea L. (Asteraceae), and its associated insect fauna was conducted in Bulgaria. The weed occurs from sea level to 1200 m mainly on roadsides (47% of populations encountered), disturbed and abandoned farmlands (40%), as well as in orchards, vineyards and fields of wheat, roses and lavender. For the first time in Bulgaria, the insect species associated with the plant were inventoried. A total of 51 insect species were collected, but only four appeared to be specific to the plant. The most dominant species and the one considered most promising as a potential biological control agent was the moth, Schinia cognata Fr. (Lepidoptera: Noctuidae). S. cognata larvae feed on the reproductive parts of the plant, and during development, one larva can consume 61 to 62 flower buds or seed heads. In Bulgaria, the moth has two generations that overlap, with maximum population densities in July and August. S. cognata is widely distributed throughoutBulgaria and was found in high densities in most of the populations of C. juncea studied. It was not observed attacking any other native plant or cultivated plants, and preliminary host-range studies of four closely related species indicated that it could only feed and develop on C. juncea. S. cognata has therefore been selected as a potential biological control agent for possible future introduction in North America.