Plant-protection and serological tests showed that raspberry yellow dwarf virus is closely related to, and should be considered of strain of, arabis mosaic virus.
Cherry trees affected by diseases of the rasp-leaf type in England, Germany, and Switzerland contained either arabis mosaic or raspberry ringspot viruses, but a virus from cherry with Eckelrader disease in the Netherlands was unrelated to either of these viruses. Arabis mosaic virus was also isolated from wild elder (Sambucus nigra L.) trees and from horse radish (Armoracia rusticana (Gaertn.). No common antigens were detected in raspberry ringspot and tomato black ring viruses although the two viruses often occur together in fields. As with tomato black ring virus, there was much evidence of geographical variation between isolates of raspberry ringspot virus from Scotland, England, and Continental Europe, but isolates of arabis mosaic virus from different countries were scarcely distinguishable.