Plum pox virus: diagnosis and spread inhibition by weed control

Plum pox virus (PPV) is a plant virus (genus Potyvirus, family Potyviridae) infecting stone fruit trees. Since the first report from Bulgaria in 1917, PPV has spread to Europe, Africa, America, and Asia. In 2015, the first identification of PPV in Korea was reported from symptomatic peaches (Prunus persica). Diagnosis of PPV is a significant issue in quarantining plants as well as in preventing disease spread. In this study, a duplex reverse transcription and polymerase chain reaction (RT-PCR) detection system was developed with two different target regions in the PPV genome. Peach trees showing variable detection efficiency for PPV were sampled over two years and analyzed with other peach trees that were confirmed as indicator plants for PPV. Based on the RT-PCR results, the highest viral accumulation of PPV was confirmed in spring and decreased with increasing temperature in summer; therefore, PPV was typically unable to be detected during summer. The inability of RT-PCR to detect the virus in summer was repeatedly observed. This study also diagnosed PPV from 9 of the 19 major weed species around PPV-infected peach trees and confirmed that Erigeron annuus is an important weed that can act as a host for the proliferation of aphids and the spread of the virus from the weed to the peach and other host crops. Therefore, performing PPV diagnosis in spring and the management of weeds such as E. annuus, which can be a host of both, the virus and the insect vector, are important ways to prevent the spread of the virus.