Virus
Viruses being intracellular pathogens employing host machinery for their propagation can not be controlled through chemical means as in the case of fungal and bacterial diseases. There are many viruses infecting the potato crop and depending upon their nature causes varied symptoms. Their control is more a management aspect and constitutes a very important component of plant health management (PHM) such that that the losses are below the economic threshold. The different components of the management strategy are quarantine which is applicable in case of viruses not present in India, cultural practices to ensure sanitation, forecasting and control of vectors of the viruses, using virus resistant varieties, eliminating viruses in cases where the sample size is small and very importantly, using healthy seed. In most cases combination of methods may have to be used in an integrated manner.