EPPO Global Database

EPPO Reporting Service no. 03 - 2007 Num. article: 2007/056

New records of Iris yellow spot virus in the USA

In the USA, Iris yellow spot virus (Tospovirus, IYSV – EPPO Alert List) has been reported from several states (Arizona, California, Colorado, Georgia, Idaho, Nevada, New Mexico, Texas*, Oregon, Utah, Washington). In June 2006, volunteer onion plants (Allium cepa) in Orleans county, New York, showed typical symptoms of IYSV. Serological and molecular tests confirmed the presence of IYSV in diseased onion plants. This is the first report of IYSV in New York State (Hoepting et al., 2007).

In western Oregon, onion (Allium cepa) and leek (A. porrum) are grown on approximately 600 ha for bulb and seed production. During surveys conducted in July and August 2006, on bulb crops (onion) and seed crops (onion and leek), typical symptoms of IYSV were observed. Symptomatic plants were collected from fields of 1 onion bulb crop, 1 onion seed crop and 2 leek seed crops. For the onion bulb crop and leek seed crops, most symptomatic plants were found near the borders of the fields. Disease incidence was low (;5%) and yield losses negligible. In the onion seed crop, symptomatic plants were found throughout the field and disease incidence was approximately 20%. According to the authors, this is the first time that IYSV has been found in the western part of Oregon (mild, maritime climate) and the first time that IYSV has been reported from leek in the USA (Gent et al., 2007).

* The EPPO Secretariat had previously no data on the occurrence of IYSV in Texas.


Gent DH, Martin RR, Ocamb CM (2007) First report of Iris yellow spot virus on onion and leek in Western Oregon. Plant Disease 91(4), p 468.
Hoepting CA, Schwartz HF, Pappu HR (2007) First report of Iris yellow spot virus on onion in New York. Plant Disease 91(3), p 327.