Prospects for biocontrol of invasive Rosa rugosa

The biota of herbivorous arthropods and pathogenic microorganisms associated with Rosa rugosa in its native and exotic ranges is reviewed. This is done as an initial step towards the identification of potential agents for biological control of this plant species invasive in Europe and North America. It is shown that more insect (but apparently not fungal) species attack R. rugosa in its native range than in its exotic range, and that most of the specialized insect and fungal enemies are confined to its native range. Among the close relatives of R. rugosa in its exotic ranges are many native species, as well as economically important crop plants. Few organisms appear to be narrowly specialized to R. rugosa, but true host specificity can only be identified through experimental testing. Based on the literature, the most promising candidates for biocontrol seem to be the aphids Myzus japonensis and Amphorophora amurensis, the leaf hopper Empoasca ussurica, the tortricid moth Notocelia longispina, the cynipid gall-wasp Diplolepis fukudae, and the rust fungi Phragmidium rosae-rugosae and P. yezoense. A screening programme is suggested, investigating the impact of these organisms on R. rugosa performance, their host specificity and the risk of undesired indirect effects in the ecosystem where agents are released. In addition, demographic studies of the target plant should be integrated to provide guidance for the stage in the life cycle most sensitive to control and, thus, enable selection of the most efficient and safe biocontrol agents.