Purple Blotch Disease Update

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Potential Biological Control for Blackberry

One of the roles of The Victorian Blackberry Taskforce (VBT) is to oversee the implementation of the Victorian Blackberry Strategy (VBS). The VBS recognises that blackberry is a complex problem which can’t be solved but can be managed by limiting its growth and spread. In order to achieve this objective it is the role of the VBT to support and encourage research into biological methods of blackberry control. The summary of this research, to determine whether purple blotch disease (pbd) (Septocyta ruborum) can be an effective biocontrol for European blackberry, is provided to bring communities up to date with progress and inform them of the current status of the research program. The funding to support the research ceased in June 2012 and the program was terminated.

Purple blotch disease is a promising tool for blackberry control under a tree canopy. Although there were releases of rust strains several years ago none are effective in shady areas. The public land estate, private remnant native forest and commercial tree crops would benefit if the research were to be continued and pbd found suitable for release. These are usually difficult areas in which to implement successful chemical control programs, for a variety of reasons. Damage to non-target species and access issues are two.

There have been excellent results in blackberry control on cleared farmland through collaborative community weed programs which restore productive capacity and protect biodiversity values. The VBT Community Partnership Program, which enables community action and builds capacity for cooperative weed management at a local level, is one of these programs. Private and public land managers work together on interface infestations when resources allow, however the current approach is not producing sustainable reductions in infestations and another tool is needed.

The VBT is working with Biosecurity Victoria to determine if the research can recommence. Funding would have to be sourced to do this and a project proposal was prepared for the Australian Weeds Committee to seek financial contributions from other States as blackberry is a Weed of National Significance. The proposal was unable to be progressed as other States were reluctant to invest (approx $8K each from 5 States).

The initial investment required to enable the research to progress for 12 months is $40k. This is an independent assessment by a research scientist previously involved in the program and which has been reviewed and confirmed by the University of Tasmania.

At the completion of the 12 months an assessment would be made as to progress and whether funding should be sought for the second year. If required, this funding is estimated to be approx $150K but would be reviewed against progress.

The National Weeds Research Summary 2011-2012 compiled by the Rural Industries Research Development Corporation recommends that the pbd research be continued as the results to date are promising.