Biological control of Salvinia molesta by Cyrtobagous salviniae in temperate Australia

A three year study of the interaction of salvinia weevil, Cyrtobagous salviniae, with Salvinia molesta was undertaken in temperate Eastern Australia. Releases of C. salviniae were made on rivers, creeks and dams from spring to mid summer of the first year and 12 sites were monitored. Eight sites were controlled by C. salviniae within 12 months, however the weevil failed to persist long term at some sites in still water habitats of creeks and dams. Better control was achieved at sites with higher temperatures and higher salvinia nitrogen levels. Biological control is an important salvinia management option in temperate regions and is now being used by weed management organisations.

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► Cyrtobagous salviniae controlled Salvinia molesta in temperate Eastern Australia in a range of water body types.
► Control in larger water bodies (rivers) was better than in creek and dams.
► Better control was achieved at sites with higher temperatures and higher salvinia N levels.
► Integrating biological control with mechanical harvesting can assist control.