Irregular Distribution of Tomato Ringspot Virus at the Graft Unions of Naturally Infected Stanley Plum Trees. James N. Cummins, Professor of Pomology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Dennis Gonsalves, Associate Professor of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Plant Dis. 70:257-258. Accepted for publication 26 September 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-257.

Graft unions of 20 14-yr-old Stanley plum trees (Prunus domestica) naturally infected with tomato ringspot virus (TmRSV) were examined visually for brownline symptoms, and rootstocks were indexed by enzyme-linked immunosorbent assay (ELISA). Samples for visual and ELISA detection of TmRSV were taken around the trunk circumference at each graft union. Static sampling revealed that both lateral distribution of TmRSV, as indicated by ELISA, and lateral development of brownline symptoms at the graft union were nonuniform. Visual samplings from all four quadrants were required to identify 90% of the infected trees, whereas ELISA samples from three quadrants were required for this degree of accuracy.

Keyword(s): prune brownline, Prunus cerasifera.