Rapid In Vitro Indexing of Grapevine Viral Diseases:The Effect of Stress-Inducing Agents on the Diagnosis of Leafroll. E. Tanne, Department of Virology, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel. P. Spiegel-Roy, Department of Plant Breeding and Genetics, and N. Shlamovitz, Department of Virology, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel. Plant Dis. 80:972-974. Accepted for publication 15 May 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0972.

The release of new virus-free propagation material and new cultivars of grapevine would be advanced if more rapid diagnostic methods could be developed. A method enabling rapid in vitro indexing of grapevine leafroll is described. Diseased explants poorly express symptoms when placed in culture. However, when placed under mild stress conditions (4% sorbitol), a variety of distinct symptoms appear within 4 to 8 weeks. This method could potentially replace the conventional 18- to 30-month indexing procedure.