Abstract: It a fleuxous filamentous virus has been isolated from Ailanthus altissimaMill. showing mosaic symptoms. It was identified as a menber of potyvirusgroup. The virus could infect twenty-one of the twenty-three plant speciescultivas from six families inoculated. The thermal inactivation point was 70-75℃. The longevity in vitro was longer than 5 weeks. The dilution endpoint was 10^-3-10^-4. It was easily transmitted by Myzus persicae Sulz. Thevirus particles were fleuxous rods, about 725nm long. The purified prepareation had an ultraviolet absorption spectra typical of a nucleoprotein (A=260/280=1.20). The virus capsid contained a single protein species with amolecular weight of 35,000 daltons. Antisera to the virus was obtained fromrabbits immunized with purified virus preparations. The virus could be"described" in ISEM tests using antisera for PVY. In addition, electron microscopyof thin sections of infected leaf tissue demonstrated the presence of severaltypes of inclusion bodies similar in appearance to inclusions prevously descri-bed in association with potyvirus infections in other plants.

Key words: Ailanthus altissima, Potyvirus, Virus disease