Propagation material is the most important factor productivity and farm sustainability, and this is especially the case in clonally-propagated crops. Plants from any particular cultivar originate from a seedling. The plant in normally evaluated in breeding plots for several years before release in the nursery system as a named cultivar. During this period there is ample opportunity for infection by one or more systemic pathogens which are carried over to its clones. The National Clean Plant Network aims to eliminate all systemic pathogens of importance from breeding accessions before they are released and massively propagated in the nursery system. The process involves traditional and state-of-the-art technologies that aim to identify systemic pathogens of concern but also discover new ones that may pose a threat to the crop. The merits of the process and the linkage to state certification programs will be discussed.