Flaming Fireweed

Abstract

Fireweed ('Senecio madagascariensis') continues to spread in coastal pastures in south eastern Australia, as well as onto the Northern and Southern Tablelands of NSW and in far north Queensland on the Atherton Tablelands. Wherever it spreads it is causing considerable angst amongst farming communities. Recognising the impact and spread of fireweed, and as a result of landholder lobbying, particularly by the Bega Valley Fireweed Association, the Australian Government funded a 2 year research project through the University of New England and CSIRO in 2010 to examine ways to better control this weed and fully assess prospects for biological control. Field sites were established at Dorrigo and Armidale in northern NSW to collect data on survival of fireweed seeds in the soil, impact of fireweed on pasture production and availability, and fireweed seedling emergence times. Initial results indicate that pasture availability to livestock is reduced where fireweed plants are growing close to one another but that seed longevity can be relatively short in the soil seed bank under high rainfall conditions. Where pasture growth is weakened e.g. through herbicide application, fireweed seedlings may germinate in large numbers out of season. An application was submitted to the Australian Weeds Committee (AWC) in September 2010 on behalf of the Australian Government to have fireweed listed as a Weed of National Significance (WoNS), but this application is still under consideration. Twelve natural enemies have been identified in initial surveys across five populations of fireweed in the Kwa-Zulu Natal Province of South Africa, including three stem borers, four flower feeders, two sap suckers, and three plant pathogens. A postdoctoral research fellow and Masters student at the University of Kwa-Zulu Natal will examine what factors keep fireweed in check in South Africa and continue quantitative studies of the weed's natural enemies including attempts to rear the species and make more specific identification.