First Record of Barley yellow striate mosaic virus, Barley stripe mosaic virus, and Wheat dwarf virus Infecting Cereal Crops in Tunisia.

A survey conducted during April 2000 to identify viruses infecting cereal crops in different regions (Beja, Bizerte, Cap-bon, Jendouba, Kairouan, Siliana, and Zaghouan) of Tunisia covered 15 barley, 21 durum wheat, and 7 bread wheat randomly selected fields. Virus incidences were determined on the basis of laboratory testing of 100 to 200 randomly collected samples from each field. A total of 5,227 random (1,654 barley, 2,546 durum wheat, and 1,027 bread wheat) and 1,430 symptomatic (451 barley, 746 durum wheat, and 233 bread wheat) samples were collected. Samples were tested for the presence of five different viruses by tissueblot immunoassay (TBIA) (1) at the Virology Laboratory of INRAT. Antisera used were for Barley stripe mosaic virus (2), Barley yellow dwarf virus (PAV serotype) (2), Wheat streak mosaic virus (3), Barley yellow striate mosaic virus (BYSMV) provided by E. Luisoni, IFA, Turino, Italy (4), and Wheat dwarf virus (WDV) provided by J. Vacke, Research Institute of Crop Production, Prague, Chech Republic. BYDVPAV was detected in seven barley (from three fields), 25 durum wheat (10 fields), and eight bread wheat (three fields) samples from all except the Siliana region. BYSMV was detected in three barley (three fields), 16 durum wheat (six fields), and four bread wheat (three fields) samples from the Beja, Bizerte, Cap-bon, Jendouba, and Siliana regions. WDV was detected in five barley (three fields), nine durum wheat (four fields), and four bread wheat (one field) samples from the Beja, Cap-bon, and Bizerte regions. BSMV was detected in 49 barley (six fields) and 25 durum wheat (five fields) samples from the Beja, Bizerte, Cap-bon, Kairouan, and Zaghouan regions. This is the first record of BYSMV, BSMV, and WDV infecting cereal crops in Tunisia, but their incidence in fields was less than 1%. However, BSMV incidence was 10.5% in one barley field from the Cap-bon region. Virus incidence in symptomatic plants was a bit higher and ranged from 0.8% for WDV in bread wheat to 6% for BSMV in barley. References: (1) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (2) K. M. Makkouk and S. G. Kumari. Rachis Newsl. 12(1/2):24, 1993. (3) K. M. Makkouk and S. G. Kumari. Rachis Newsl. 16(1/2):74, 1997. (4) R. G. Milne et al. Intervirology 25:83, 1986.