Monitoring of Plum Pox Virus concentration at different plant heights throughout the year in prunes (Prunus domestica) in Argentina

Abstract

Sharka, caused by Plum pox virus (PPV), is the most important viral disease of stone fruits worldwide. PPV was detected for first time in Argentina in 2004 and since then many efforts have been made to eradicate it. To optimize sampling and virus detection by DAS-ELISA, 8 PPV-positive prune trees (P. domestica, cv. 'D´agen') were selected and sampled monthly from September 2008 to August 2010. The plant tissue collected was the one available at the sampling time (leaves, flowers or buds). The samples were taken from each of the four tree scaffolds at three different heights (basal, medium and apical). Variability of absorbance levels in each month was analyzed with Principal Components Analysis and sampling schemes were compared with non parametric variance analysis. This is the first study made in Argentina to tracking PPV relative virus concentration throughout the year. As described previously by many authors in the north hemisphere the highest levels of virus concentration, in both studied years, were found in spring (October and November) using flowers and young leaves. The scaffold basal height showed the highest PPV concentration in these two months. High variation of relative virus concentration levels were found among months, within and between years. Regarding different parts of the plant, relative virus concentration decreased from the base to the apical part of the scaffold, indicating that sampling should be performed at a basal height. This study will contribute to the optimization of DAS-ELISA PPV detection in Argentina.