INCIDENCE OF CYMBIDIUM MOSAIC AND ODONTOGLOSSUM RINGSPOT VIRUSES AND THEIR SIGNIFICANCE IN ORCHID CULTIVATION IN SINGAPORE

A survey of cymbidium mosaic virus (CyMV) and odontoglossum ringspot virus (ORSV) in orchids cultivated in Singapore was conducted during 1988-1991. Of the 12 genera from four major commercial orchid farms, 54.6% of the plants were infected with CyMV, 4.0% with ORSV, and 14.2% with both CyMV and ORSV. Among the 29 genera from the orchid nursery of Botanic Gardens, 34.5% were infected with CyMV, 0.3% with ORSV, and 8.3% with both CyMV and ORSV. From the 13 orchid genera cultivated in tissue-culture flasks in the tissue culture laboratory of the Botanic Gardens, 50.5% were infected with CyMV, none with ORSV alone, and 0.5% with both CyMV and ORSV. These findings emphasize the need to implement a virus-free certification programme that would greatly enhance the management of these two prevalent viruses in the Singapore orchid industry.