English (or Scotch) broom (Cytisus scoparius (L.) Link) is a perennial, leguminous shrub of the Fabaceae (pea) family. In native vegetation, it can form dense thickets which exclude native species. Dense infestations are highly difficult to control, and the required interventions to manage these infestations are likely to cause severe off-target impacts and require extensive follow up works. As such, management of these infestations can be cost-prohibitive.
English broom has invaded approximately 150 000 ha of Victoria and is yet to reach maximum habitat potential. Within the Alpine National Park (ANP), the majority of the English Broom infestation is within the Mitta Mitta catchment in the Lakes and East Alps Park Area downstream of Glen Wills. Its distribution extends along the Mitta Mitta River from the Big River Bridge to the upper reaches of Lake Dartmouth.
Biological control can potentially reduce the vigour and spread of target species with minimal labour inputs. Two English broom biocontrol agents with demonstrated capacity to weaken the health and/or reproductive capacity of broom plants have been successfully introduced in the eastern alps: the seed-feeding beetle (Bruchidius villosus Fabricius); and the broom gall mite (Aceria genistae Nalepa).
Parks Victoria has implemented two forms of community participation to assist in the dispersal of broom biocontrol agents: (1) holding a workshop in collaboration with other agencies to educated and train community groups in the dispersal of these agents to public or private land; and (2) engaging volunteers to assist in the targeted redistribution of agents within the Alpine National Park.
Although the success of redistribution works has not yet been determined, over successive years release sites will be revisited to determine the presence or absence of agents.
Primrose, K.A. and Brida, N. (2016). Volunteers as dispersal agents for biocontrol of English broom in the Victorian eastern alps. Plant Protection Quarterly. 31(2), 67-69.