YELLOWS OF LETTUCE AND SOME OTHER VEGETABLE CROPS IN THE NETHERLANDS CAUSED BY BEET WESTERN YELLOWS VIRUS

A virus isolated from lettuce (Lactuca sativa), endive (Cichorium endivia), witloof chicory (C. intybus), and spinach (Spinacia oleracea), and from some weeds was shown to be beet western yellows virus (BWYV) by its host range, particle morphology and serology. It resembled previously described European isolates but differed from American strains in its inability to infect Beta vulgaris, Brassica pekinensis and Raphanus sativus. The most useful host for routine indexing was Crambe abyssinica. Virus particles in purified preparations stained with uranyl acetate were isometric, ca. 27 nm in diameter. Purified virus reacted with antiserum to an American strain of BWYV in infectivity neutralization gel diffusion and serologically specific electron-microscopy tests. The field reaction to BWYV of cultivars of lettuce, other Lactuca species and some Cichorium species was investigated and differences in symptom expression were observed. On the basis of observations during two seasons BWYV appeared to be widely distributed but seemed of minor economic importance to lettuce growing. It may be a potentially important pathogen of endive and chicory. © 1979 Koninklijke Nederlandse Planteziektenkundige Vereniging.