Articles
CONTROL OF VIRUS DISEASES IN VEGETATIVELY PROPAGATED ORNAMENTAL CROPS
Domestic and international trade in ornamentals, both as finished products (e.g. cut flowers, foliage plants, potted flowering pots) and propagation material (e.g. cuttings, bulbs, corms) are expanding constantly.
The growing demand for high quality and disease-free planting material, the high sanitary standards imposed by many countries for importation of plant material, and the increasing amount of international trade, have highlighted the significance of virus diseases in ornamental crops.
A large number of ornamental plant species, of high economical value, are propagated vegetatively through cuttings, tubers, bulbs, corms etc.
Production of vegetatively propagated plant material is based on building up stocks from source plants.
Viruses usually enter a propagation system at the breeding or germplasm level and are transmitted vertically down the propagation chain.
The ultimate outcome of this process is virus-infected progeny.
In many cases, virus and virus-like agents are symptomless in their hosts.
Plants infected with a single virus tend to acquire a complex of viruses which results in severe distortion of entire plants or plant parts e.g. flowers.
Since no practical treatments to cure virus-infected plants in the field are available, elimination of viruses from propagation material is currently the method used to obtain virus-free material.
For convenience, the term ‘viruses’ will be used here to include virus-like agents, viroids and mycoplasma-like bodies (MLOs).