Identification of viral diseases affecting barley and bread wheat crops in Yemen

A survey to identify virus diseases affecting barley and bread wheat crops at different locations in Yemen was conducted during 15 - 24 September 2004. The survey covered 13 barley and 23 bread wheat fields, which were randomly selected. The identification of the viruses and their incidence was determined by laboratory testing of 100 - 200 randomly collected samples and 2 - 20 symptomatic samples from each field by tissue blot immunoassay using antisera to six cereal viruses (Barley yellow dwarf virus-PAV, Barley stripe mosaic virus, Barley yellow striate mosaic virus, Wheat streak mosaic virus, Barley yellow dwarf virus-MAV and Cereal yellow dwarf virus-RPV). The most common virus detected on the randomly collected samples was the Barley yellow dwarf virus-PAV, with an overall incidence of 7.0% in barley and 4.3% in bread wheat, followed by the Barley stripe mosaic virus. Two cereal fields had a total virus disease incidence of 21% or higher. The highest virus disease incidence detected in barley fields was 28.9% in the El-Bon valley, which was infected with Barley stripe mosaic virus and Barley yellow dwarf virus. Other viruses, such as Barley yellow striate mosaic virus, Cereal yellow dwarf virus-RPV and Barley yellow dwarf virus-MAV were rarely detected. This is the first report of Barley stripe mosaic virus, Barley yellow striate mosaic virus, Barley yellow dwarf virus-MAV, Barley yellow dwarf virus-PAV and Cereal yellow dwarf virus-RPV naturally infecting cereals in Yemen.