Agoston Janos
Tue, 05 Jun 2007 13:26:45 PDT
Dear Robert and all,

As a student in horticulture we have learned, that viruses are obligate parasites (they cannot live and propagate without a host, but they may crystallize and survive if they drie out).

My professor said, that if a plant is infected with virus it cannot be cured out. Well at least the science thinks this. Now there are Capsicum annuum (pepper) breeders, who say plants may have an immune system, but when a plant shows symptoms it is better to killit before it infects others.

One viricide plant exists: Melissa officinalis. It is held, that this plant's sap is doing harm for the viruses, so this plant cannot get a virus infection. But if you spray an infected one (not Melissa) it still cannot be cured out.

My opinion from which plants are infected with virus in the trade: Oxalis lasiandra (all), Oxalis triangularis subsp. papilionacea 'Birgit' (all) -> symptome: too small offsets, rare flowering.

Narcissus Jonquilla 'Quail' (nearly all)
Narcissus Double 'Bridal Crown' (nearly all) -> next year they will be much more cheaper, cause in the Netherlands the stock is overpropagated...
Narcissus Large Cupped 'Accent' (about 10%)

You may find Hyacinthus Mosaic Virus in Muscari from Holland also.

Lilies: it is held, that Lilium lancifolium var. splendens is infected with Lily Simptomless VirusNever buy plants from DeRee or BouRee cause nearly all lilies and Hostas are infected!

Hosta Virus X may not show sympoms in the first 3 years after infection! he common and cheap hostas can be infected. Nowdays if wholesalers offer one bud Hosta rhizomes the plants may come from micropropagation, and most of them are now virus free.

In Alliums I found Leek Yellow Mosaic Virus this year. Allium rosenbachianum (at least it was told it is true to name, but never looked after the corrct ID) is very very susceptible here.

At a bulb forcer I saw, that all Iris × hollandica is more or less showing mosaic on the foliage.

I have infected Zantedeschia albomaculata and Z. rehmannii here, and maybe Pinellia tripartita and Typhonium robustum. I try to get rid of Hosta plantagine which have Hosta Virus X and most of my lilies.

Tulip breaking or leaf mosaic can be caused by 6 different viruses, if there are 2 or more virus is present the symptomes are much more visible.

I hope I can learn soon the use of Wiki so pictures will be posted... (if there are clearly visible symptomes...)

Jani, Z5a, Hungary

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