CymMV and ORSV are two of the most prevalent viruses of orchids, both predominantly present worldwide. They are highly stable viruses that possess similar biological and epidemiological characteristics, and are therefore, commonly co-infected. During single-infection, these viruses may produce symptomatic or asymptomatic diseases in some orchid genera, however plants infected with these two viruses produce severe disease symptoms that are more pronounced than a single-infection [9] and [10]. Orchids that are affected include Cymbidium, Odontoglossum, Phalaenopsis and Oncidium, and symptoms include mottling, ridging, curling and distortion of flowers and abnormal growth and stunting of plants. Symptom severity during co-infection is attributed to the synergism between ORSV and CymMV. Their co-existence results in enhanced RNA replication, hence causing the viral loads to be highly accumulated in infected plants [11]. This synergism greatly affects the flower quality and quantity, making CymMV and ORSV two economically important viruses in orchid cultivation worldwide that are responsible for significant financial losses in the orchid industry.