TULPINI DE PLUM POX VIRUS IDENTIFICATE LA PIERSIC IN ZONA CENTRAL-SUDICĂ A BULGARIEI

Abstract

Sharka disease, caused by plum pox virus (PPV), was detected on peach (Prunus persica (L.) Batsch.) for the first time in Bulgaria in 1989. Nowadays PPV is widespread in peach crops grown under varied agro-ecological conditions. The current study aimed to determinate the PPV strains spread in peach in six agro-ecological micro-regions located in three provinces (Plovdiv, Pazardzhik, Stara Zagora) of South Bulgaria. Altogether 70 PPV accessions, collected from 23 peach cultivars, were analysed by reverse transcription – polymerase chain reaction (RT-PCR) using primer pairs discriminating isolates of PPV-M, PPV-D and PPV-Rec strains. The summarized results revealed that PPV-M and PPV-D were identified in 85.7% and 8.6 % of the analysed samples, respectively. Both strains were detected at the highest infection rates in Pazardzhik province. Co-infection by both strains PPV-M and PPV-D was registered at the rate of 5.7 % of the tested accessions. PPV-Rec strain was not identified neither single nor in co-infection with the other strains. It has found differences in strain status in each of the studied orchards located in one and the same province. Likely the continuous increase of the PPV infection rate in peach is due to the prevalence of PPV-M strain, considered the epidemic form of the virus, and possible arising of higher virulent PPV-D variants. In that case, it should be applied all reasonable measures for containment of the virus spread and protection of the tree health.