First Report of Alfalfa mosaic, Bean common mosaic, and Broad bean stain viruses in Macrotyloma axillare.

Chlorotic mottling, mosaic, malformation, and rolling were observed on leaves of the forage legume species Macrotyloma axillare at the International Livestock Research Institute seed multiplication site in Debre Zeit, Ethiopia, in September 1999. M. axillare is a drought-resistant forage legume and a vigorous plant that is palatable to livestock. Disease assessment studies have shown that there can be a 46% reduction in the pod and dry-matter yield of plants infected with Alfalfa mosaic (AMV), Bean common mosaic (BCMV), and Broad bean stain (BBSV) viruses. Diseased leaf tissue (100 g) was tested for AMV, BCMV, and BBSV by antigen-coated plate enzyme-linked immunosorbent assay. Eighteen samples from four diseased plants were replicated six times for each virus. Nicotiana benthamiana was used as a negative control. Visual inspection and data obtained from the enzyme immunosorbent assay (EIA) reader indicated that M. axillare was infected with BCMV, BBSV, and AMV. A pairwise comparison of the mean EIA data for the viruses and against the healthy control also indicated that M. axillare was infected with BCMV, BBSV, and AMV. This is the first report of BCMV, BBSV, and AMV on M. axillare. These viruses are of importance in quarantine because they can reduce pod yield in legumes by 40% (1). Reference: (1) A. V. Bogdan. 1977. Tropical Pasture and Fodder Plants. Longman Group Limited, New York.