Virescence of Horseradish in Illinois. Catherine E. Eastman, Section of Economic Entomology, Illinois Natural History Survey, Champaign 61820. Gerald A. Schultz, Section of Economic Entomology, Illinois Natural History Survey, Champaign 61820; Jacqueline Fletcher, Department of Plant Pathology, University of Illinois, Urbana 61801; and Keykavous Hemmati and George N. Oldfield, Boyden Entomology Laboratory, University of California, Riverside 92521. Plant Dis. 68:968-971. Accepted for publication 30 April 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-968.

A virescence-inducing agent, transmitted experimentally by Circulifer tenellus, was found in field-grown horseradish in Illinois. Symptoms in flowering horseradish, Madagascar periwinkle, radish, and wild mustard included virescence, phyllody, shortening of internodes, and bunching of leaves with occasional axial proliferation. Mycoplasmalike organisms of typical polymorphic morphology were found in mature sieve elements from virescent periwinkle test plants. The virescence agent was found periodically in mixed infections with Spiroplasma citri in brittle root-diseased horseradish.

Keyword(s): Armoracia rusticana.