Advice
Hellebore black death
Symptoms
Black
streaking and mottling of the tissues along or between the
leaf veins are the main symptoms. The black marks may be in
a ringspot pattern or in lines, which pass down the leaf stalks
to the main stem of the plant. The blackening is associated
with serious distortion and stunting of the leaves and stems,
and the flowers may also be affected.
Cultivars and hybrids of Helleborus x hybridus are particularly affected.
Cause
For the first time, since the problem of hellebore 'black death' was reported at the beginning of the 1990s, virus particles have been observed in plants showing typical symptoms. Molecular work carried out so far suggests that these particles are probably related to the carlaviruses, a type of virus. Hellebore aphid (Macrosiphum hellebori) is a strong candidate as the vector of the disease but more work is needed to confirm it. Antibodies produced against the virus can now be used in enzyme-linked immunosorbent assay (ELISA) to detect the disease from hellebore stocks.
Control
Dig up all infected plants and destroy them immediately to reduce the risk of spread.
For a report on
research at RHS Garden Wisley on hellebore
black death click here (46KB)
 |
To view this document you will need a copy of Adobe Acrobat Reader. We strongly recommend that you download the latest version to prevent problems viewing the documents. This is available free from the Adobe website. Click on the logo to go to the website. |