September 1997, Volume 18 No. 3
This issue of BNI has an emphasis on the biological control of weeds. Weed biological control has a long and successful history, starting with the biological control of prickly pear cactus in the early part of the twentieth century. Efforts at biological control of alien weeds with introduced organisms have increased exponentially since then. Most targets to date have been weeds of rangelands, forests, water-ways and other areas where infestations are so remote and/or extensive that economical chemical or mechanical control is not possible. More recently, alien weeds have been perceived as a growing problem for conservation because they displace native plants and change the communities which depend upon them. From both the production and conservation perspectives, bio-logical control is emerging as a preferred strategy for ecological and sustainable management of invasive weed problems.
A substantial milestone in this area has been the allocation by the Global Environment Facility in 1997 of about $8 million for control of water hyacinth on Lake Victoria in Africa. Noteworthy for its scale, its environmental slant and its strong emphasis on biological control, this project also illustrates the enormous potential for spreading the benefits of weed biological control experience between countries.
As interest in weed biological control grows, practitioners face important challenges. Issues of safety and resolution of conflicts of interest have always been a feature of weed biological control. Recent studies in the USA revealing that biological control agents for cactus and thistles have infested populations of rare indigenous plants give cause for concern by ecologists, and show that the priorities which have governed past programmes are not those which will govern future biological control in a more environmentally aware World.
The weed biological control practitioner enjoys a range of sources of up-to-date information on the discipline. Besides this journal, which publishes abstracts from about 65 recent papers every quarter, a four-yearly international conference is organized by the weed biological control community, the proceedings of which give an authorita-tive and very current summary of work underway. The latest proceedings* cover a meeting held in Stellenbosch, Republic of South Africa in January 1996. The next meeting will be in Bozeman, Montana, USA in 2000. For an historical perspective on weed biological control, a database of biological control** is maintained and regularly updated by Dr M. Julien of CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Australia. Finally, for those interested in the more bioherbicidal aspects of weed biological control, a newsletter*** is produced on a regular basis with information on current activities at many institutions worldwide.
The two review articles in this issue of BNI review work on some serious composite weeds of the Old World tropics and subtropics: Parthenium hysterophorus and Ageratina riparia. They reveal much about current weed biological control practices, particularly the diversification of agents from insects into fungi, and the need for safety testing of candidate agents. In the next issue of BNI, we will be publishing the 1995 FAO Code of Conduct for the Import and Release of Biological Control Agents and continuing our emphasis on biological control introductions and safety, as they apply to weed and other targets of biological control.
*Moran, V. C.; Hoffman, J. (eds) (1996) Proceedings of the 9th International Symposium on Biological Control of Weeds, Stellenbosch, South Africa, January 1996. University of Cape Town, 563 pp.
**Julien, M. (1992) Biological Control of Weeds. A World catalogue of agents and their target weeds, 3rd edition. [4th edition in prep.] Wallingford UK; CAB INTERNATIONAL/ACIAR, 186 pp.
***IBG News produced by the Inter-national Bioherbicide Group. For further information contact the Editor: Dr Louise Morin, CRC for Weed Management Systems, CSIRO Ento-mology, GPO Box 1700, Canberra, ACT 2601, Australia