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Etiology

Curly Dwarf Mosaic Disease of Beans from El Salvador. J. P. Meiners, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705; H. E. Waterworth(2), R. H. Lawson(3), and F. F. Smith(4). (2)Research Plant Pathologist, U.S. Plant Introduction Station, Glenn Dale, MD 20769; (3)Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705; (4)Research Entomologist (Retired), Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705. Phytopathology 67:163-168. Accepted for publication 20 August 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-163.

A virus related serologically to squash mosaic virus and quail pea mosaic virus was associated with a disease of Phaseolus vulgaris widely distributed in experimental plots and commercial fields in El Salvador. Prominent field symptoms were mosaic, dwarfing, downward curling of leaves, and rugosity. Field symptoms were reproduced in some bean cultivars mechanically inoculated with extracts from naturally infected leaves. However, symptoms ranged from mild mosaic to lethal top necrosis among the 30 cultivars tested. Fourteen other species of legumes were susceptible, and seven were immune. Of 41 nonleguminous genera tested, Gomphrena globosa and Chenopodium quinoa were the only susceptible species. A polyhedral virus, measuring 23 to 25 nm in diameter, designated bean curly dwarf mosaic virus (BCDMV), was associated with the disease. Antiserum to this virus reacted only with the homologous antigen and with quail pea mosaic virus. However, antisera to quail pea mosaic, squash mosaic, and Echtes Ackerböhnemosaik viruses reacted with BCDMV. None of the 47 other antisera reacted with purified BCDMV. Mexican bean beetles and spotted cucumber beetles transmitted BCDMV. Properties of BCDMV most closely resemble those of viruses in the comovirus group, but it is distinct from bean rugose mosaic virus of Costa Rica, which also is a comovirus. Bean curly dwarf mosaic virus should be considered to be a strain of quail pea mosaic virus.