NL-8 Strain of Bean Common Mosaic Virus in Idaho Bean Seed Fields. R. L. Forster, University of Idaho Research and Extension Center, Kimberly 83341. J. R. Myers, G. I. Mink, and M. J. Silbernagel. University of Idaho Research and Extension Center, Kimberly 83341, and IAREC, Washington State University, Prosser 99350. Plant Dis. 75:537. Accepted for publication 15 January 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0537C.
During August 1989, plants of six bean (Phaseolus vulgaris L.)
cultivars resistant to pathogroups I (type strain) and V (NY-15 strain)
of bean common mosaic virus (BCMV) showed mosaic symptoms
in fields in Canyon and Twin Falls counties, Idaho. Fifty-eight
tissue samples of these cultivars (VI 60, VI 114, VI 126, NW 410,
Othello, and Kardinal) were tested by ELISA using four BCMV
monoclonal antibodies (1) and by bioassay on differential cultivars.
Nine samples were positive for BCMV serotype A (NL-8 strain) and
20 were positive for serotype B (I). The balance were negative or
gave ambiguous results. This is the first time isolates belonging to
pathogroup III (NL-8 strain) were identified and confirmed in Idaho;
pathogroups I and V were reported previously. Serological assays
of seed lots used for planting (parent lots) and subsequently harvested
seed lots detected BCMV serotype B in 8% of the VI 60 parent lot
and serotypes A and B in 6% of the harvested UI 114 seed lot but
not in any other lots.