The National Clean Plant Network (NCPN) is a USDA-funded program focused on specialty crops, such as berries, citrus, grapevines, fruit trees, roses and sweet potatoes. The clean planting material is distributed to nurseries for further propagation and to growers. The NCPN operates under high standards for the production of true-to-type and pathogen-tested (mainly viruses) plant material. There are five Clean Plant Centers located in California, Florida, Missouri, New York and Washington states....