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Occurrence of the Beet Leafhopper-Transmitted Virescence Agent in Red and Daikon Radish Seed Plants in Washington State. T. R. Schultz, Department of Agronomy and Soils, Washington State University, Pullman 99164-6420. M. E. Shaw, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 75:751. Accepted for publication 15 January 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0751D.

Red radish (Raphanus sativus L) and daikon radish (R. sativus cv. 'Iongipinnatus') seed plants showing symptoms of late proliferation of virescent flowers with elongation and fusion of sepals were observed during early July 1990 before harvest throughout much of the Columbia Basin of Washington State. Reduced pod development, seed number, and seed size were associated with these phyllody symptoms. DNA extracted from symptomatic tissue and Southern blotted to nylon membranes hybridized with a cloned fragment of the beet leafhopper-transmitted virescence agent-mycoplasmalike organism (BLTVA-MLO) plasmid DNA obtained from the type strain FC-83-13. The BLTVA-MLO has a wide host range and is transmitted by the beet leafhopper (Cin:uliju trnellUJ (Baker» . Healthy leafhoppers transmitted the viresence agent from naturally infected radish to periwinkle (Catharanthus roseus (L.) G. Don) and daikon. Transmission to daikon caused a premature induction of flowering, virescence, and phyllody, characteristic of BLTVA-MLO (1). This pathogen has been detected previously in California and southern Idaho (2), but this is the first report of its occurrence in Washington State.

References. (1) D. A. Galino et al. Plant Dis. 73:850, 1989. (2) M. E. Shawe et al. Piant Dia. 14:252. 1990.