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Serological and Host Range Evidence for the Occurrence of Beet Western Yellows Virus in Europe. James E. Duffus, Plant Pathologist, Crops Research Division, ARS, USDA, U.S. Research Station, Salinas, California 93901; G. E. Russell, Principal Scientific Officer, Plant Breeding Institute, Trumpington, Cambridge, England. Phytopathology 60:1199-1202. Accepted for publication 16 March 1970. DOI: 10.1094/Phyto-60-1199.

Observations of symptoms on weeds and crop plants in Britain during 1968 and 1969 suggested that beet western yellows virus (BWYV) was present in hosts reported to be immune to beet mild yellowing virus (BMYV). Transmissions from plants showing BWY-like symptoms, using Myzus persicae as vector, demonstrated that they were infected with a persistent aphid-transmitted virus resembling BWYV in transmission characteristics and host range. The host range of virus isolates from Capsella bursa-pastoris and lettuce growing in eastern England was similar to that of some BWYV strains from California, but differed in several important respects from that of BMYV. The three isolates studied in detail infected and produced symptoms on Beta macrocarpa, Brassica rapa, Lactuca sativa, Capsella bursa-pastoris, Nicotiana clevelandii, and Claytonia perfoliata, but did not infect Beta vulgaris, Raphanus sativus, Chenopodium capitatum, or Sonchus oleraceus. These three English isolates were readily transmitted by M. persicae, which had acquired virus by feeding on clarified sap through artificial membranes. In density-gradient columns containing sap from infected plants, the positions of infectious zones corresponded closely with those in gradients containing BWYV. In infectivity-neutralization tests, antisera prepared against seven strains of BWYV neutralized infectivity of the English isolates, and specific antisera against the isolates neutralized infectivity of five BWYV strains as well as the isolates. Antisera prepared against sap from virus-free plants did not affect the infectivity of any virus strain or isolate. The results of these investigations show for the first time that BWYV occurs outside the USA, but do not help to clarify the relationship between BWYV and BMYV.