Author
Raelene M Kwong
rae.kwong@agriculture.vic.gov.au
Agriculture Victoria
Bundoora
Coauthors
Jackie Steel, Agriculture Victoria, Bundoora, Australia
Tonya Wiechel, Agriculture Victoria, Bundoora, Australia
Sam Van Holsbeek, University of the Sunshine Coast, Sippy Downs, Australia
Marian Seier, CABI, Berkshire, United Kingdom
Norbert Maczey, CABI, Berkshire, United Kingdom
Philip Weyl, CABI, Delémont, Switzerland
Michal Sochor, Palacký University, Olomouc, Czech Republic
Abstract
European blackberry (Rubus fruticosus aggregate) is a declared Weed of National Significance in Australia due to its invasiveness and broad impacts on agriculture, forestry, and the environment. Biological control in Australia began in the 1970s with surveys across the Mediterranean in Europe and the selection of the rust fungus Phragmidium violaceum, tested against predominant blackberry taxa at the time. As P. violaceum has shown variable performance across taxa, a strategy to broaden its genetic diversity was pursued by introducing additional strains from southern France.
Taxonomic revision identified Rubus anglocandicans as Australia’s most widespread taxon, prompting UK-range natural enemy surveys in 2021. Phylogenetic comparisons, however, revealed genetic differences between Australian and UK accessions, raising questions about whether Australian populations represent a biotype of R. anglocandicans or a related species within the Discolores series. The Eurasian Rubus fruticosus aggregate remains obscure and poorly resolved in its native range, complicating the search for new biocontrol agents.
The proposed new phase centres on a genomics-guided, adaptive biocontrol framework: (1) characterizing Australian blackberry population genetics and identifying ancestral lineages within a broad native genotype landscape; (2) linking these insights to native-range enemies for targeted surveys; (3) developing a multicriteria decision tool that fuses ecological, climatic, historical, and molecular data to prioritize taxa and sites and (4) integrating biocontrol agents with current management through glasshouse and field trials. This approach aims to guide targeted surveys and inform the selection of promising biocontrol candidates within a forestry-relevant context.
Keywords
Rubus fruiticosus
Genomics
Blackberry
Natural enemy surveys
Native range
Highlights
Variable rust efficacy across European blackberry taxa limits consistent impact in Australia
Obscure Eurasian taxonomy and genotypic diversity hinder agent matching.
Multicriteria decision tool to guide surveys and inform selection of new agents