The International Camellia Society [ TOPICS ] [Pests & Diseases ] [ Virus ]

It is likely that most of your camellia plants are virus infected.
So should we be bothered if they look healthy?----We should.

1) Yellow mottling of leaves and white mottling of flowers has been known on camellias for many years and has been frequently attributed to virus or viruslike agents. The desease can be transferred by grafting. Virusfree cultivars can be made 'variegated' by infection with the virus.

2) A virus can only be identified - and named - with electron microscopy. In camellias, this was not yet really successful, and thus there is doubt wether or not there is a single strain, or several, of virus, or viruslike agents.

3) Single cultivars may or may not show signs of infection. Some cultivars show leaf mottling only if they are not in their best physiological condition.

4) Once infected, it is not possible to cure the plant.

5) Seedlings are, usually, free of virus.

6) Virus infection is mostly man-made. The infection is easily carried to healthy specimen by cutting flowers or scions, where knives and scissors are not cleaned between different bushes. Whether other vectors like aphids are important is unknown.
The cleaning procedure of cutting tools is not established. Somebody claimed that a clean virus is thus transferred. Using new and sterilized knifes works safely, but is too expensive.

7) My leading sentence (likely most plants are infected) cannot be prooved presently. In other genus, however, we have a similar situation (worldwide cultivation and distribution of cultivars), but the plants show more easily signs of infection. About 20 years ago, almost any orchid you bought was infected and displayed black spots on the leaves after a while. It is generally believed that the vigor of an infected plant decreases. I heard of tremendous efforts of forrestry experts to get and establish virus free wood propagation.

8) So why should we be concerned with our camellias, when they grow and flower in apparently appealing form as they do? The answer is that some cultivars may do even better if virus free. Since presently nobody can demonstrate this, we like to question the experts: Is the vigor of a variegated form less or equal to the unvariegated? (Please send your observation!)

9) With orchids, it was possible to establish virus free propagation by meristem culture in vitro. This culture is presently not possible in camellias, or other hardwoods. I try to find an expert in in vitro culture for an article to be posted here. Please wait.

10) Dr. Jean Creze near Nantes -France- has established a method which might work, he grafts camellia vegetative buds in vitro on seedlings. I promise to post more on his efforts and results, as well as generell methods to get rid of the virus, quite soon on this place.

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