The rust fungus produces small spores that are windborne and naturally spread from sites where it is well established. We have seen natural wind dissemination of up to 15 km one year after a release. Since the Crofton weed rust fungus was approved for release in Australia in May 2014, it has been has been released at several sites across NSW in partnership with the community. The fungus is now well-established at some sites from which it can be redistributed.
To enhance natural spread, community members may consider redistributing the fungus to sites where it is absent using one of the three methods outlined in these guidelines: 1) potted plants method, 2) layering method and 3) transplanting method.
The step-by-step pictorial guide for each method is presented in separate tabs. A PDF file of the three pictorial guides can be downloaded here.Download
The preferred methods are potted plants or layering using potting mix as these options do not involve the movement of soil from one site to another and thus reduce the risk of spread of soil pathogens and weed seeds.
Simply transferring rust-infected leaves to a new site is highly unlikely to lead to establishment of the fungus. The fungus shuts down very quickly once infected material is removed from a plant and thus does not produce the necessary spores for new infections to occur.
Establishment of the fungus in the field depends on the environmental conditions present at the time the redistribution activities are performed. The hot summer months should be avoided.