ZLATA STEF AN AC and MERCEDES WRISCHER

The virus earlier reported from spinach (S. oleracea) from Yugoslavia under the tentative name of spinach latent virus has been shown — by symptomatology in test plants, properties in sap, transmission through seed and serological reactions — to be identical with the ilarvirus characterised under the same name in the Netherlands. After mechanical inoculation the Yugoslav isolate (SpLV/ /H) of spinach latent virus infected 22 out of 32 species from nine families, causing reactions somewhat stronger than those described for two Netherlands isolates (GE36 and Sp20— 9). The sap from infected C. quinoa was infective after 10 min at 55 but not at 60° C, after dilution to 10-3 but not to 10~4, and after 6 but not 8 days at 22° C. The sap extracted with phosphate buffer containing TGA re­ tained infectivity considerably longer. SpLV/H was transmitted through a high rate of seed from infected C. quinoa (60°/o), N. clevelandii (90%), N. megalosiphon (95%) and S. oleracea (60%). It was also transmitted through pollen, causing in­ fection of seed [C. quinoa (21%), S. oleracea (56%)] and of pollinated spinach plants. Electron microscopy of infected C. quinoa and B. vulgaris saccharifera leaf cells revealed, in the cytoplasm and in ’small vacuoles’, groups of small vesicles surrounded by a unit membrane. In the cells of control plants the vesicles were found sporadically, but only inside the ’small vacuoles’. The ultrastructural modi­ fications mentioned have not been described in other ilar­ virus infections.