Identification and seasonal variation of viral diseases of chickpea and lentil in Iran
Field surveys were conducted to identify viral diseases affecting lentil (Lens culinaris Medik.) and chickpea (Cicer arietinum L.) in Iran during the 2001 and 2002 seasons. The survey covered 100 chickpea and 34 lentil fields, all of which were randomly selected. The types of viruses present and virus incidence were determined on the basis of the laboratory testing of 100-200 randomly collected samples, in addition to 20-25 symptomatic samples taken from each field. A total of 15,106 chickpeal and 6,080 lentil samples were randomly collected; symptomatic samples, 2,017 from chickpea and 797 from lentil, were collected and tested, by tissue-blot immunoassay, for the presence of 10 viruses that affect legumes. Laboratory tests showed that, in the chickpea fields, Bean leafroll virus (BLRV) and Chickpea chlorotic dwarf virus (CpCDV) were most common, followed by Taba bean necrotic yellows virus (FBNYV) and Beet western yellows virus (BWYV). In lentil fields, BLRV and Pea enation mosaic virus (PEMV) were most common, followed by FBNYV and Brood bean stain virus (BBSV). Other viruses detected at a low incidence in chickpea were PEMV, Alfalfa mosaic virus (AlMV), Bean yellow mosaic virus (BYMV), Cucumber mosaic virus (CMV), Pea seed-borne mosaic virus (PSbMV), and Soybean dwarf virus (SbDV). In lentill, low incidences of PSbMV, BYMV, CpCDV and AlMV were detected. It was evident that virus spread, in both chickpea and lentil crops, was comparatively higher during 2001 than was the case during 2002. In chickpeas, around 64.7% of the fields surveyed during 2001 had a virus disease incidence of 6% or higher, whereas in 2002 only 22.5% of the surveyed fields fell into this category. In lentils, all of the fields surveyed had a virus incidence of 6% or higher in 2001, whereas only 38.1% of the fields fell into this category during 2002.