Abstract
Bean leaves with symptoms similar to those caused by bean common mosaic virus (BCMV) were obtained from a plant grown from seed of a plant introduction line growing in Puerto Rico. Differential seed transmission in two bean cultivars (Stringless Green Refugee and Topcrop) inoculated with leaf extracts revealed that the plant was infected with BCMV and cucumber mosaic virus (CMV), designated the PR strain. CMV-PR produced two types of symptoms on beans: mild vein banding on certain cultivars, or top necrosis on others. Host range included 8 genera and 12 species of legumes and 16 species of non-legumes. Physical properties are similar to major strains of CMV. Purified CMV-PR reacted serologically with CMV-C and CMV-S antisera in gel diffusion tests. Virions measured 25 to 27 nm. CMV-PR was transmitted by Myzus persicae to bean and cowpea, and in seed harvested from infected bean and cowpea plants. Survival of the virus in bean and cowpea seed stored for 6 months and 1 year, respectively, enhances the possibility of wide geographic distribution through movement of infected seed.