LOCALISATION OF CHERRY LEAF ROLL VIRUS IN PRUNUS AVIUM X P. PSEUDOCERASUS ROOTSTOCKS

Previous work has shown that Prunus avium x P. pseudocerasus hybrid cherry rootstocks are resistant to infection when inoculated with cherry leaf roll virus (CLRV) by P. avium bark grafts, and Cropley suggested that this resistance might be caused by a hypersensitive reaction of these hybrid rootstocks to CLRV.

Work has continued with one clone of P. avium x P. pseudocerasus.
Plants inoculated with CLRV (isolate CH125) by F12/1 bark grafts in August 1969 developed gumming and necrosis around the inoculation grafts.
During the second, third and fourth years after inoculation, CLRV was transmitted to herbaceous plants by manual inoculation with bark macerates, but only with bark that was partially necrotic, usually within 3–8 cm of the inoculation grafts.
No transmissions resulted from bark taken more than 10 cm from the inoculation grafts, nor from bud, leaf or flower extracts.
The virus was readily transmitted from bud, leaf, flower and all bark extracts of F12/1 plants similarly inoculated with the same virus isolate.

The localized necrotic reaction of these rootstocks to this strain of CLRV resembles the reaction of Shirofugen cherry to Prunus necrotic ringspot and prune dwarf viruses, but these two viruses caused no local lesions in the stems of P. avium x P. pseudocerasus hybrid rootstocks, and the viruses became systemic.

IX International Symposium on Fruit Tree Virus Diseases

R. Cropley, L. Giunchedi, H.R. Cameron

https://doi.org/10.17660/ActaHortic.1975.44.6