First report of Iris yellow spot tospovirus on onions in Réunion
In August 2003, onion plants (Allium cepa) growing in Réunion showed symptoms characterized by irregularly shaped chlorotic or necrotic lesions on the leaves. In 2004, 84 symptomatic samples were collected from two onion fields, one intended for seed production and the other for bulb production. Studies (DAS-ELISA, RT-PCR) revealed the presence of Iris yellow spot tospovirus (IYSV - EPPO Alert List) in 4 samples (out of 6) and 34 samples (out of 78) of onions for bulb and seed production, respectively. This is the first report of IYSV in Réunion island. Further studies were then done on other Allium crops, and IYSV was detected in leek (A. porrum), garlic (A. sativum) and shallot (A. cepa var. ascalonicum). In all Allium crops surveyed, Thrips tabaci (which is a vector of IYSV) was widespread, whereas Frankliniella occidentalis (which is not a vector) was only occasionally observed. The situation of Iris yellow spot tospovirus in Réunion island can be described as follows: Present, first found in 2003 on several Allium crops (A. cepa, A. porrum, A. sativum, A. cepa var. ascalonicum).
Robène-Soustrade I, Hostachy B, Roux-Cuvelier M, Minatchy J, Hédont M, Pallas R, Couteau A, Cassam N, Wuster G (2005) First report of Iris yellow spot virus in onion bulb and seed production fields in Réunion island.
New Disease Reports, Volume 11: February 2005 - July 2005.