The analysis of the viral status for the PPV, PDV and PNSRV viruses in peach and nectarine tree mother plants at RSFG Constanta

The most frequent viruses in peach and nectarine trees are the Plum pox potyvirus (PPV), Prune dwarf ilarvirus (PDV) and Prunus necrotic ringspot ilarvirus (PNSRV). Between 2012 and 2016 the annual retesting carried out on two Basis mother plant collections founded in 2008 and 2014 highlighted infected plants of the afore-mentioned species. Harvesting of the samples occurred every year at the end of May - beginning of June from plants that did not display any symptoms. In order to establish an accurate diagnosis, several methods were applied. The DAS-ELISA serological technique and the the AgriStrip immunochromatographic test was used to detect PPV. Biological testing for PDV and PNSRV used the GF 305 indicator and the DAS-ELISA serological method. Twelve of the samples were identified as positive for the PPV virus with both methods of testing. The DAS-ELISA method revealed seven samples infected with PNSRV and six with PDV. The serological method revealed mixed infections as well: PPV + PNSRV for two trees and PPV + PDV for one tree. Testing on ligneous indicator plants created through grafting in isolated conditions after a period of time of 3 to 24 months confirmed the diagnosis for PDV and PNSRV. The GF 305 indicator displayed symptoms for the PNSRV for the same plants identified as positive by means of the DAS-ELISA test. For the PDV virus the symptoms were visible only in three of the tested plants.