Elm leaf beetle 'Xanthogaleruca luteola' (Muller) dispersal across south eastern Australia (1989-2011)

Elm leaf beetle, Xanthogaleruca luteola (M ller), was first detected in Victoria, Australia, in 1989. It is a serious pest of elm trees, particularly European elms such as English elm Ulmus procera Salisb., Dutch elm U. x hollandica Mill., golden elm U. glabra Huds. 'Lutescens', and weeping elm U. glabra 'Camperdownii'. Overseas experience suggests the beetle is capable of spreading over long distances with the assistance of humans. Reports of elm leaf beetle received by state agencies since 1989, and the results of delimiting surveys, were used to determine the progress of spread of the pest in Australia. The pattern of elm leaf beetle spread in south eastern Australia can be characterised as stratified dispersal, a combination of long-distance (or jump) dispersal and local diffusion dispersal. This paper reviews the surveys taken over many years to detect elm leaf beetle in large parts of Victoria, southern New South Wales and Tasmania, and its recent detection in parts of South Australia. This paper maps the dispersal of elm leaf beetle through the four south eastern Australian states and uses the degree-day calculation to demonstrate differences in its life cycle across these states. This paper also consolidates over 20 years of elm leaf beetle dispersal knowledge from south eastern Australia.