Building international collaboration for the biological control of invasive Rubus species
Facilitators: Marion Seier (CABI UK), Raelene Kwong (Agriculture Victoria, Australia), Costas Zachariades (Agricultural Research Council, South Africa)
Key question and/or issue
How can researchers and stakeholders, e.g. growers, commercial Rubus industry, conservation organizations and biosecurity agencies work together internationally to accelerate the development, testing, and implementation of effective biological control solutions for invasive Rubus species, their hybrids, and cultivars?
Background information
A number of invasive Rubus species are currently targeted by classical biological control (CBC) programmes. Invasive European blackberries (Rubus fruticosus agg.) represent one of the most widespread and costly weed problems in temperate regions worldwide. The complex nature of the Rubus species aggregate comprising numerous microspecies and hybrids poses significant challenges for biological control. While agents such as Phragmidium violaceum (blackberry leaf rust) have had local success, their impact is often patchy, and further research is needed to discover and test additional agents.
Mysore raspberry (Rubus niveus), introduced into several countries around the globe, has become highly invasive in Galapagos and Hawaii; in its native Himalayan range numerous rust fungi, particularly Phragmidium species, have been recorded from this Rubus species. However, their taxonomy is complex and to date none of the rust accessions sourced has proven to be compatible and/or sufficiently virulent to the invasive plant genotype(s). A Septoria leaf-spot pathogen is currently undergoing assessment as a potential CBC agent.
Yellow Himalayan raspberry (Rubus ellipticus), invasive in Hawaii, has been the subject of a long-standing CBC initiative and the potential of selected natural enemies as CBC agents has been highlighted in the literature; however, to date none of these has been comprehensively evaluated.
American bramble (R. cuneifolius) has been under investigation in South Africa, with molecular studies revealing the presence of several apomictic genotypes (one widespread in Rubus section Cuneifolii and three widespread in Rubus section Arguti), with genotypic matches to native North American populations yet to be discovered.
The West Asian species R. armeniacus (Armenian blackberry) is a problematic invasive plant in Europe and the western United States. A related group of at least two genotypes of Eurasian origin, likely incorrectly called R. “praecox” or R. “anglocandicans”, is invasive in the western US, South America, and Australia. Genotypic diversity in the secondary ranges has been partly characterized, as well as the genotypes’ susceptibility to rust fungi, but the primary distribution areas are still insufficiently known, not to speak of their taxonomy and nomenclature.
International collaboration is key to improving efficiency, sharing data and live material, coordinating host-specificity testing, clarifying Rubus taxonomy and phylogeny, and developing common monitoring protocols and navigating Access and Benefit Sharing and the Nagoya protocol. This workshop provides a forum to align efforts, identify shared priorities, and explore partnership and funding opportunities to progress biocontrol of invasive Rubus species globally.
The facilitated workshop will be discussion-based, focusing on identifying collaborative opportunities rather than presenting research results. The scene will be set by a brief overview of the current biocontrol status of problematic Rubus spp.
Discussions will be structured across:
- Global search for new biocontrol agents- pooling resources for surveys to discover new agents, sharing results and cultures among countries with similar Rubus problems, sharing host-specificity testing protocols
- Genetic and taxonomic research- efforts to clarify taxonomy and genetics of invasive Rubus spp., use of genomics to map global genetic diversity and identify common invasive genotypes, standardised nomenclature to enable matching agents to the right taxa
- Data, tools and infrastructure sharing- collaborative online data platform on natural enemies and host taxa
Partnership models and funding opportunities: cross-country consortia - Agreement on next steps to stay connected and progress collaborative initiatives.