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First Record of Faba Bean Necrotic Yellows Virus and Beet Western Yellows Luteovirus Affecting Lentil and Chickpea in Pakistan

In an intensive survey of lentil and chickpea fields and Research Station plots in the Punjab province of Pakistan, more than 6,505 samples were collected and tested for presence of 14 different viruses by the tissue-blot immunoassay (TBIA) procedure (2). All antisera used were virus specific, including those for faba bean necrotic yellows virus (FBNYV) (1) and beet western yellows luteovirus (BWYV) (ATCC 647). Counting plants with virus symptoms greatly underestimated virus incidence in lentil crops but was a better guide to virus occurrence in chickpeas. Overall, about 1 in 5 plants of lentil were virus infected with 15% of fields having incidence over 50%. In contrast, levels of infection were mostly low in chickpea. Pea seed-borne mosaic virus (PSbMV) followed by cucumber mosaic virus (CMV), both of which are aphid- and seed-borne, were the most abundant viruses in lentils, but also occurred in chickpea. PSbMV incidence was 17% in lentil and 0.1% in chickpea fields, whereas CMV incidence was 1% in lentil and 0.1% in chickpea fields. The other viruses found on both lentil and chickpea were FBNYV, BWYV, chickpea chlorotic dwarf geminivirus, chickpea luteovirus, and alfalfa mosaic alfamovirus. Because of yield losses associated with PSbMV infection, the high levels of infection in lentils are cause for concern. This is the first record of FBNYV and BWYV affecting lentil and chickpea in Pakistan, but their incidence in the fields where they have been detected was low (less than 1%). FBNYV was detected in three of the 33 lentil and two of the 34 chickpea fields surveyed. BWYV was detected in two of the 33 lentil and three of the 34 chickpea fields surveyed.

References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994.