Color break in orchid flowers

Color break in orchids, once thought to occur solely in Cattleyas, has been reported in Odontoglossum, Cymbidium, Vanilla, Epidendrum, Encyclia, Oncidium, Phalaenopsis, and many other orchid genera. At one time, color break was thought to be caused by two distinct strains, mild and severe, causing both petals and sepals to be marked with irregular areas which develop at random and which are lighter or darker than the normal flower color. There was no malformation or distortion of flowers in the mild strain. However, the two strains are now classified as Odontoglossum ringspot tobamovirus (ORSV). ELISA was used to verify the presence of the virus. Both petals and sepals from the Cattleya and Phalaenopsis were marked with irregular areas that developed at random and were lighter or darker than normal flowers. In some Cattleya flowers the virus caused necrotic flecking.