Incursion preparedness: Anticipating the arrival of an economically important plant pathogen Xylella fastidiosa Wells (Proteobacteria: Xanthomonadaceae) and the insect vector Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) in Australia

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is animportant insect vector of the xylem-limited plant pathogen Xylella fastidiosa Wells et al. that causesdiseases in numerous plant species including food and feedstock crops, ornamentals and weeds. Both the pathogen and the vector are native to the Americas, and H. vitripennis has demonstrated highinvasive ability but to date neither has been detected in Australia. The Australian wine grape, tablegrape, peach, plum, nectarine and citrus industries are particularly concerned about the arrival ofX. fastidiosa and H. vitripennis because of the potential economic impact on these important commodities.Other commodity producers in Australia should also be concerned about this vector-pathogen, inparticular the ornamental plant, avocado and olive industries. Past interceptions of H. vitripennis and thepotential for X. fastidiosa to be moved in live plant material or within live vectors indicate the need forrapid detection of an incursion in areas considered at high risk. This requires identification of regionsthat have climatic and environmental conditions conducive to X. fastidiosa and H. vitripennis establishmentas well as a detailed knowledge of their respective potential host plant ranges in new areas. Theseclimatic regions and host plant species can then be targeted for monitoring in order to detect anincursion at an early stage. CLIMEX modelling has shown that much of coastal Australia hastemperatures suitable for survival of both the vector and pathogen. A range of other requirements inaddition to suitable climate must, however, be satisfied for an incursion to lead to establishment,proliferation and spread.This review article provides information that shows that the Australian environment is suitable for the establishment of H. vitripennis and that Australian native plant species are likely to serve as X. fastidiosa hosts and subsequent pathogen sources, and highlights future researchdirections.