Rick S. Llewellyn
CSIRO Sustainable Ecosystems, Adelaide
David J. Pannell
University of Western Australia, Perth

The threat of herbicide-resistant weeds to crop production makes sustainable weed and herbicide management an important issue for agricultural extension agencies throughout the world. In this study, we examined the effectiveness of an intensive training workshop in modifying the weed-managementrelated perceptions and adoption intentions of farmers. We found that the extension activity had significant impacts on farmers’ perceptions about several aspects of the herbicide resource management decision, including the speed of resistance development, the potential for a population of herbicide-resistant weeds to return to herbicide-susceptibility, and the economic value of several treatments. As a consequence, the workshop appears to have altered the adoption intentions of a significant number of participating farmers, including adoption of a strategy to prevent development of resistance to the herbicide glyphosate. We argue that extension can be more effective if it targets grower perceptions identified as being influential in the adoption decision, particularly if those perceptions are known to be inaccurate.

Key words: Adoption, decisions, herbicide resistance, integrated weed management, IWM, integrated pest management, IPM, perceptions.