Invasion risk of Homalodisca coagulata, vector of Xylella fastidiosa in grapevine-growing regions of the world
Homalodisca coagulata (Homoptera: Cicadellidae – EPPO Alert List) is an efficient vector of Xylella fastidiosa (EPPO A1 list) and its spread to California (US) has resulted in a chronic Pierce’s disease problem for grapevine growers. In USA, Pierce’s disease occurs mainly in areas with mild winters (winter temperatures not falling below 1–4°C). H. coagulata probably originates from south-eastern USA and north-eastern Mexico. Climate matching studies (using CLIMEX) were done to determinate the potential geographical distribution of H. coagulata and grapevine strains of X. fastidiosa in California and other grapevine-growing regions of the world. Model predictions indicated that suitable climatic conditions for H. coagulata and Pierce’s disease strains existed in almost all grapevine-producing regions of the world. However, it was found that regions north of California are not able to sustain populations of either the vector or the disease because of cold stress. It was found that H. coagulata could establish in the major grapevine-growing regions of New Zealand, Australia, France (Bordeaux), Spain (Andalucía, Cataluña, Galicia, País Vasco, Valencia), central and southern parts of Italy. However, cold stress would exclude it from Bourgogne and Champagne regions of France, provinces of Northern Italy and Central Spain. CLIMEX predicted that cold stress would exclude Pierce’s disease from most of New Zealand, Tasmania and Victoria state in Australia, from all France, and from northern and central areas of Spain and Italy. Grapevine-growing areas of Chile (from Valparaiso to Concepción close to the Pacific coast) and the Western Cape Province in South Africa appear vulnerable to both the disease and its vector.
Hoddle MS (2004) The potential adventive geographic range of glassy-winged sharpshooter, Homalodisca coagulata and the grape pathogen Xylella fastidiosa: implications for California and other grape growing regions of the world.
Crop Protection, 23(8), 691-699.