Fruit tree production can be severely impacted by the introduction and spread of harmful viruses and virus-like pathogens that reduce plant vigor and yield, product quality, and in some cases, lead to death of the afflicted plants. Control of these pathogens is limited, for there is no cure, only preventative measures to reduce their introduction and spread, and elimination of the source of inoculum in the environment.

The three participating National Clean Plant Network Fruit Tree centers perform the first role, helping prevent the introduction of harmful and economically important viruses into the U.S. fruit tree industry. We do this by carrying out a rigorous testing regime to detect targeted pathogens in fruit tree cultivars submitted to the centers by private, state, and federal stone and pome fruit breeding programs from across the country, and around the world. If pathogens are detected, virus elimination is performed, and the plants tested, and retested, to ensure that the pathogen is gone.

The three centers have harmonized their testing programs so that stakeholders across the country can rest assured that whichever center they obtain propagative material from, it has been tested for the same pathogens. The testing approach for producing stonefruit (Prunus sp.), is shown below: