S-137. Transboundary movement of plant viruses: A case study of India

Seed trade and international exchange of germplasm play an important role in the long-distance dissemination of a destructive virus or its virulent strain. One such example is the introduction of Peanut stripe virus into the US and India. With the liberalization under the World Trade Organization regime the possible introduction of seed-transmitted viruses has been enhanced. In India as per the Plant Quarantine (Regulation of Import into India) Order, 2003, the Directorate of Plant Protection Quarantine and Storage is responsible for enforcing quarantine regulations. Import of bulk material for sowing/planting purposes are authorized only through five of the twenty nine Plant Quarantine Stations. The National Bureau of Plant Genetic Resources has been empowered for quarantine processing of imported germplasm and transgenic planting material meant for research purposes. A number of exotic viruses have been intercepted in imported germplasm which includes the ones yet not reported from India viz., Barley stripe mosaic virus on barley and wheat, Broad bean stain virus on Faba bean, Cherry leaf roll virus on soybean and French bean, Cowpea mottle virus on cowpea etc. Also certain other viruses are intercepted which are not known to occur on the those hosts in India on which they were intercepted. Besides vectors or their biotype able to transmit the native viruses may also be introduced. The introduction of Bemisia tabaci biotype B into India is such an example that has spread the Tomato leaf curl virus in a rampant form in Karnataka and Andhra Pradesh. This highlights the importance of quarantine in ensuring biosecurity in the country.