A new hope for the biological control of blackberry

Blackberry is one of the top ten weeds of priority to Australian grazing industries. Over 9 million hectares of productive pastures across the Southern Australia Livestock Research Council geographic region have been invaded by impenetrable thickets of European blackberry. In 2006, the economic cost of blackberry from lost pasture production and control costs was estimated to be in the order of $103 million per year. Biocontrol using the leaf rust fungus has achieved some success against susceptible genotypes of blackberries in high rainfall regions, but greater impacts are required to provide effective, long-term control in drier regions. A recent Meat and Livestock Australia (MLA)-funded feasibility study identified crown and cane-boring insects in Europe that could make ideal candidates for biocontrol as they reduce the biomass of blackberry infestations and slow their rate of spread. The objective of this project is to conduct host specificity testing on the blackberry can-boring sawfly, enabling an application for its release into Australia to be developed and submitted to the federal government for approval. The outcomes of the project is to obtain approval to release a new biocontrol agent for blackberry to help combat this aggressive weed in Australia.