Development and improvement of detection technologies to control sharka disease

Abstract

First reported in Bulgaria in 1933, Plum pox virus (PPV), the causal agent of sharka disease, has spread throughout Europe, despite its classification as a quarantine pest. In recent years, PPV has reached North Africa, America, and Japan. Sharka disease causes severe yield losses to the stone-fruit industry. As is typical for plant virus diseases, there is neither cure nor effective treatment of infected trees. Detection and quarantine measures are relied upon to delay or halt virus spread. PPV detection has led to the harmonization of preventive measures such as spring season surveys of nurseries and orchards, the use of certified virus-free plants, removal of infected trees, and creation of quarantine zones. In summer, while a majority of susceptible cultivars exhibit PPV symptoms, some tolerant cultivars are symptomless, and infected fruits become marketable. This situation led us to analyze fruits through RT-PCR to evaluate levels of PPV in these symptomless marketed fruits. Because evidence of PPV infection was previously found in some fruit samples, this study may have implications for the export and marketing of fruits from PPV-tolerant plum cultivars.