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• PCR-based techniques are the most widely used diagnostic tools for virus indexing. • Out of 681 total genera, only 49 genera were reported for virus infection. • Cypripedioideae is the most affected among the sub-family in Orchidaceae. • Production of Virus-free orchids using in vitro techniques is a desirable approach. The maximum number of genera in the family Orchidaceae are well represented by their floricultural importance and are exported globally for trade exchanges. However, economic loss due to viral diseases has a profound impact on the orchid trade industry worldwide. Further, enduring phytosanitary certificates and undergoing stringent quarantine measures for virus-free orchids pose a major setback during the exchange of breeding materials between regions or countries. Fortunately, the spread of orchid viruses can be effectively controlled if proper diagnosis of viral diseases is made at an early stage and strict application of appropriate eradication methods are deliberated in a holistic approach. This bibliographic review highlights the substantial advancements in the diagnostic and eradication techniques of orchid viruses during the past few decades. The review shows that PCR-based techniques, which are represented as the "gold standard" method, are the most widely used diagnostic tools because of their accuracy, simplicity, and sensitivity. Considering the large diversity of orchids, only 7.2% of the genera belonging to the sub-families Epidendroideae, Orchidoideae, Cypripedioideae, and Vanilloideae have been detected for virus infection. The tribes Podochileae, Thaieae, Nervilieae, Gastrodieae, Xerorchideae, Triphoreae, Wullschlaegelieae, Tropidieae, Sobralieae, and Neottieae of the family Orchidaceae are under-represented. In vitro techniques, including meristem culture, thermotherapy, chemotherapy, and their combinations, represent the most desirable and effective approaches for orchid viral elimination. The use of cryotherapy, a simple technique based on cryopreservation, should have a high priority for viral elimination from infected orchids. This review could pave the way forward for comprehensive research on the production of virus-free orchids. [ABSTRACT FROM AUTHOR]

• ORSV was found to be more prevalent than CymMV with the incidence percentages of 53.5% and 46.4% respectively. • Mixed infection of ORSV and CymMV was found to be 35.7%. • The Nucleotide sequences of ORSV and CymMV CP genes from Meghalaya showed high sequence identities of 96.90–99.56% and 96.91–99.66% respectively with other available sequences in Genbank. Odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV) are the most prevalent viruses infecting orchids all around the world. These viruses cause a serious threat to the orchid industry as they can spread from infected plants to healthy plants through vegetative propagation, contaminated tools, and human hands. This result in negative vigour of infected plants, showing stunted growth, producing fewer flowers, and decreasing flower quality. In this study, 84 leaf samples of orchids were collected from nine horti-hubs and orchid nurseries in Meghalaya. The orchid leaf samples were subjected to multiplex RT-PCR amplification using gene-specific primers targeting the coat protein (CP) genes of CymMV and ORSV. The most prevalent virus detected was ORSV with a 53.5% incidence while CymMV showed a 46.4% incidence. Mixed infections of ORSV and CymMV were detected in 30 samples (35.7%). The nucleotide sequences of ORSV and CymMV CP genes from Meghalaya showed high sequence identities of 96.90–99.56% and 96.91–99.66%, respectively when compared to other sequences in GenBank. The phylogenetic relationship among ORSV isolates and CymMV, based on infected host or geographical origin, showed no clear-cut clustering of isolates. [ABSTRACT FROM AUTHOR]