Community involvement in releases of the Crofton weed rust fungus
Crofton weed plants infected by the rust fungus were used for releases because 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.
Rust-infected plants grown in pasteurised soil or in rock wool were distributed to community members at field events or via the post, respectively.
Production of rust-infected plants for distribution to community members via post
Release of the rust fungus
Three to four rust-infected plants in a plastic-lined box or in individual milkshake containers, obtained at a field event or via the post, were placed within a dense stand of Crofton weed in the shade, where there was no chance of livestock grazing on them. Water was added to the containers to ensure plants remained alive for 2-3 weeks. The release area was identified by attaching a piece of flagging tape on a nearby bush or tree, or using another form of marker to ensure the area could be relocated for monitoring. Plants were not transplanted in the ground as this was deemed too stressful for them.
Community members were asked to revisit release sites at at 4-5 weeks and 3 months after release to inspect for rust symptoms on field-growing Crofton weed plants, record observations and provide feedback to the research team.
Monitoring the impact of the rust fungus
The easiest approach to monitor long-term impact of the fungus on crofton weed is to identify a suitable photopoint at the release site and take photos at the time of release and in subsequent years. The photopoint can be marked with a post or indicated in some other ways so that successive photos of the same area are taken. The photopoint should not be obstructed by tree growth in the future and ideally the photo should be taken from south to north to minimise shading. The photo taken should ideally have a permanent feature in it, such as a distinct tree, to help future comparison between photos.
Example of a photopoint, with photographs taken each year following the release of the Crofton weed rust fungus.
For more details on long-term impact monitoring download the following instructions: