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Walnut blackline

Scientific Name
Cherry leaf roll virus
Scientific Author
(Virus: Nepovirus)

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Diagnostic Images

Host Symptoms
Symptoms on the canopy Used with permission from University of California Statewide IPM Program. Copyright, for use see University of California URL link
John Mircetich University of California
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Diagnostic Images (3)
Diagnostic Notes
Cherry leaf roll virus (CLRV) is associated to different symptoms on different hosts. On English walnut (Juglans regia) propagated on seedlings of Northern California black walnut (Juglans hindsii), natural hybrid Paradox (J. hindsii x J. regia), Chinese wingnut (Pteriocarya stenoptera) and several species of Juglans, this virus causes a disease called Walnut blackline.


The key symptom of walnut blackline disease is a gradual girdling by a narrow, black, necrotic strip of cambium and phloem tissues at the rootstock-scion union, resulting in decline and death of the English walnut scion. On English walnut propagated on paradox rootstock, the disease develops an extensive necrosis of bark in the rootstock that is delineated by the scion at the graft union (Mircetich & Rowhani 1984). Information about symptoms on other hosts is given by the Crop protection Compendium (2005).

The virus:

Cherry leaf roll virus has bipartite genome, RNA and belongs in the genus Nepovirus. It is transmitted by mechanical inoculation, grafting, pollen and nematodes. A detailed description of CLRV is provided by B├╝chen-Osmond (2003).
More Information
Specimen Contact
Dr Jose R. Liberato
Liberato JR
08/08/2006 03:11 AEST
Last Updated
27/07/2016 07:42 AEST
Liberato JR (2006) Walnut blackline (Cherry leaf roll virus ) Updated on 7/27/2016 7:42:04 AM Available online: PaDIL -
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Free for use under the Creative Commons Attribution 3.0 Australia License