First report of Iris yellow spot tospovirus on onion in Colorado (US)
In September 2001, a new disease was observed on onions (Allium cepa) growing in a field in Larimer county in northern Colorado (US). Symptoms included straw-coloured, dry, tan, spindle-or diamond-shaped lesions on the leaves of onion plants. The presence of Iris yellow spot tospovirus (EPPO Alert List) was detected in diseased plants. It is recalled that a similar disease of onion had also been reported in Idaho. The EPPO Secretariat had previously no data on the occurrence of Iris yellow spot tospovirus in the United States. Further studies will be made to assess the extent and severity of the disease in other onion-growing areas of the country. The situation of Iris yellow spot tospovirus in USA can be described as follows: Present, found in one onion field in Colorado, symptoms observed in Idaho.
Schwartz, H.F.; Brown, W.M. Jr; Blunt, T.; Gent, D.H. (2002) Iris yellow spot virus on onion in Colorado.
Plant Disease, 86(5), p 560.