VIEW ARTICLE

Sustained Cytospora-resistance in Italian Prune Cultivars Infected with Prunus Ringspot Virus. A. W. Helton, Department of Plant and Soil Sciences, University of Idaho, Moscow 83843; Phytopathology 64:1410-1413. Accepted for publication 3 June 1974. DOI: 10.1094/Phyto-64-1410.

Italian prune trees (Prunus domestica) infected with Prunus ringspot virus (PRSV) and PRSV-free trees were inoculated with Cytospora cincta to determine the magnitude of induced resistance to subsequent infections by Cytospora. Depressed expansion rates of secondary infections indicated that (i) Cytospora invasion was more vigorous in Italian prune trees on peach rootstock (P. persica) than on plum rootstock (P. cerasifera), (ii) PRSV-induced resistance to Cytospora was stronger in trees on peach root than in trees on plum root, and (iii) PRSV-induced resistance to Cytospora was additive with new Cytospora-induced resistance, particularly in trees growing on peach rootstock.