ISHS Acta Horticulturae 110: V International Symposium on Virus diseases of Ornamental Plants
DISSEMINATION OF VIRUSES OF ORNAMENTALS AND APPROACHES TO REDUCING SPREAD AND IMPROVING METHODS OF DIAGNOSIS |
| Author: | R.H. Lawson |
| Abstract:
An assessment of the problem of spread of viruses in ornamental crops implies knowing the current distribution of these viruses. Although the distribution of many viruses in ornamental crops is worldwide, the distribution of others is not known with certainty. In this report I will not attempt to identify the distribution of viruses in detail. Instead, I will present some of the information on the occurrence of viruses in ornamental crops that I have received from virologists and phytosanitary officials in five countries on three continents. Further, I will comment on possible approaches to reducing the risk of moving viruses without severely limiting commerce in plant material. Finally, I would like to suggest some possible areas for additional research, improvement in some existing methods and possible new procedures for virus disease diagnosis. The most commonly mentioned viruses in certification and testing programs in the export and import of ornamentals are listed in Table 1. Many of the viruses on this list are not newly described pathogens. Rather, they are viruses that have been known for many years and diagnostic procedures have been developed for detecting many of them. However, some of the agents are still prevalent in crops in international commerce. Rapid expansion in the commercial development of new crops and in the production of traditional crops has occurred during the past few years. Production has expanded into new geographical areas that allow producers to grow and market a crop at less cost compared to traditional growing areas. Central and South America, Africa, and the Middle East receive a range of propagating material of different genera and species. These stocks are grown into products that are shipped to traditional centers in Europe and North America where they are marketed. More than 35 countries grow and distribute plants from over 30 families and more than 60 genera are shipped to countries that did not previously receive foundation stock for use in their production. Large volume production in the new and expanding growing areas has resulted in the continuous supply of many crops to North America and Europe that were formerly available only seasonally. The use of traditional growing structures in cooler climates has been supplanted by more open structures or open field culture. This change in production procedures has resulted in conditions that may more rapidly promote pathogen spread. | |
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