First Report of Natural Infection of Euonymus japonica var. microphylla by Alfalfa Mosaic Virus. M. Turina, Istituto di Patologia Vegetale, Universita degli Studi, Bologna, Italy 40126. M. G. Bellardi, and C. Rubies-Autonell, Istituto di Patologia Vegetale, Universita degli Studi, Bologna, Italy 40126. Plant Dis. 78:09251. Accepted for publication 5 May 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0925B.
In September 1993, disease symptoms were observed on the foliage of Euonymus japonica Thunb. var. microphylla Jacq. growing in an ornamental garden in Emilia-Romagna (northern Italy). Symptoms on young leaves varied. The mildest consisted of chlorotic blotches with indefinite margins, including green islands. Also observed were yellow spots and rings (with concentric lines), and chlorotic or yellow oak-leaf patterns. The leaves were small and deformed. Symptomatic leaves were collected and analyzed for virus by the protein A sandwich enzyme-linked immunosorbent assay (PAS-ELISA) technique. The polyclonal antisera tested were those to the viruses reported on various species of Euonymus: tobacco necrosis, strawberry latent ring spot, tomato ring spot, cherry leaf roll, and cucumber mosaic. Antisera to arabis mosaic and alfalfa mosaic (AMV) viruses were also tested. PAS-ELISA only revealed the presence of AMV. All mechanical inoculations from symptomatic E. japonica leaves were made by using 0.1 M Na-K phosphate buffer, pH 7.0, containing 0.2% Na2SO3. Among the numerous inoculated herbaceous plants, Chenopodium amaranticolor Coste & Reyn., Phaseolus vulgaris L., Vigna unguiculata (L.) Walp. subsp, unguiculata, and Ocimum basilicum L. showed visible symptoms typical of AMV. PAS-ELISA and electron microscopy of ultrathin sections confirmed the presence of AMV in both C. amaranticolor and E. japonica. To our knowledge, this is the first report of AMV in Euonymus.