The release and establishment of two biological control agents of horehound (Marrubium vulgare L.) in south-eastern Australia

Emma Wills, Keith Turnbull Research Institute, Department of Natural Resources and Environment, CRC of Weed Management Systems, PO Box 48, Frankston, Victoria 3199, Australia.


In 1991 a survey of the native range of horehound, Marrubium vulgare L. in Europe was conducted to identify potential biological control agents for Australia. Four insects were chosen for closer investigation; a plume moth, Wheeleria spilodactylus (Curtis), a skipper butterfly, Carcharodus boeticus Rambur, a clearwing moth, Chamaesphecia mysiniformis (Boisduval) and a seed beetle, Meligethes rotroui Easton. Host specificity testing of W. spilodactylus began in 1991 at Keith Turnbull Research Institute in Frankston, Victoria and in 1993 it was approved for release.

In 1994 host specificity of C. mysiniformis was performed in France and approval for release was gained in 1996. Initial attempts to begin host specificity testing for C. boeticus and M. rotroui failed, and future attempts have been halted. In the spring of 1998 a redistribution program for W. spilodactylus was initiated. A total of 32 release sites in Victoria, New South Wales, South Australia and Tasmania were visited to determine establishment of W. spilodactylus and the potential for redistribution of insects from the sites. At 90% of the sites visited the biological control agent had established and of those, 41% were at a stage that the collection and redistribution of W. spilodactylus to new sites was possible.


Plant Protection Quarterly (2000) 15 (1) 26-28.