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