A Two-Year Survey of TSWV Occurrence in Globe Artichokes in Sardinia (Italy)

Globe artichoke, grown over an area of approximately 13,000 ha, is a major horticultural crop in Sardinia (Italy). The first reports of severe symptoms of plant stunting, chlorosis, distortion and necrosis of leaves and globes, date back to the early 2000s. In 2004 Tomato spotted wilt virus (TSWV) was detected on plants collected in a district in the north of the island (Valledoria, Sassari) where the disease was particularly severe. To monitor the spread of disease epidemics, the occurrence of TSWV in the main artichoke-growing areas in the region was surveyed for two years. Approximately 2,000 samples from 114 and 85 sites, in 2008 and 2009 respectively, were analyzed by tissue print hybridization using a TSWV-specific probe. Infected plants were found both in northern districts other than that where the disease was first reported, and in artichoke fields located in the central part of the island. A reduction in the severity of outbreaks, recently noticed by growers, was also evident in our survey, which showed a decrease in disease incidence in the districts initially hard-hit by TSWV epidemics. So far, the Southern areas of Sardinia, where most of the nurseries for production of artichoke plantlets are located have not been affected by the disease.