Tospoviruses infecting Ruscus racemosus (Danae racemosa) in Liguria

• Published in: Journal of plant pathology Vol. 89; no. 3; p. S32
• Main Authors: Bellardi, M G, Vicchi, V, Benni, A, Restuccia, P
• Format: Journal Article
• Language: English
• Published: 01-12-2007
• Subjects: Impatiens necrotic spot virus; Tomato spotted wilt virus
• ISSN: 1125-4653

Ruscus racemosus (Danae racemosa) is an ornamental species with decorative foliage whose branches are used in flower arrangements. In the Ligurian Riviera (northern Italy) this shrub is cultivated on a surface of 330 ha and the cut foliage produced is almost all exported to Europe and the United States. In 2005-06, surveys of R. racemosus crops in the Sanremo area, revealed different types of leaf symptoms consisting of concentric yellow and necrotic rings, necrotic spots (from a few mm to ca 1 cm in size), necrosis and bronzing of the leaf lamina. In 2005, the percentage of diseased plants showing necrotic rings in the open field was about 60-70%; similar percentages of symptomatic plants were also observed in 2006. Preliminary electron microscope observations ("leaf dip") did not show the presence of filamentous virus particles. Considering that ten years ago Impatiens necrotic spot virus (INSV) was found infecting D. racemosa in Portugal (Louro D., Acta Hortic. 431: 99-105, 1996), testing by DAS and PAS-ELISA and RT-PCR was done to check the presence of tospoviruses. Single infections by Tomato spotted wilt virus (TSWV) and INSV were detected in plants showing necrosis and spots on the leaves. However, when in mixed infection, these viruses were associated with the other types of leaf symptoms described, and to premature death of the plants. This survey confirms once again the great variability of symptoms induced by tospoviruses in ornamental species and that their spreading in Liguria is increasing.