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Techniques

Improved Mechanical Transmission of Tomato Ringspot Virus to Prunus Seedlings. M. W. Bitterlin, Former graduate research assistant, Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456; D. Gonsalves(2), and R. Scorza(3). (2)Professor, Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456; (3)Research horticulturist, Appalachian Fruit Research Station, Kearneysville, WV 25430. Phytopathology 77:560-563. Accepted for publication 17 September 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-560.

The efficiency of different methods to transmit tomato ringspot virus (TmRSV) to Prunus seedlings (mainly peach) was compared in the greenhouse. Virus infection was determined by enzyme-linked immunosorbent assay (ELISA). Treatments varied as to virus isolate, inoculum source and preparation, seedling age, environmental conditioning of seedlings before inoculation, and inoculation technique. The highest and most consistent transmission rate was obtained with the “knife-slash” technique, which involved slashing stems of 3- to 10-mo-old seedlings 100–150 times with a contaminated razor blade. This method was repeatable with three biologically different isolates of TmRSV. Leaf rubbing combined with heat treatment of seedlings before inoculation was generally more effective than leaf rubbing alone, but the transmission rate was not consistent. The knife-slash method enables the evaluation of a wide range of TmRSV isolates on peach, which is essential in the development of cross-protection as a strategy to control peach stem pitting, as well as the rapid screening of Prunus germ plasm for TmRSV resistance. The Peach Yellow Bud Mosaic, Apricot, and Staff isolates induced symptoms on peach (oak-leaf pattern on leaves, leaf distortion, and stunted growth), whereas the Chickadee isolate did not.