Disease Note.

A New Viral Disease of Pea (Pisum sativum) Caused by Widens Mosaic Potyvirus. T. Nagata, CNPII/EMBRAPA, C.Postal. 218, 70359-970. A. N. Dusi, CNPII/EMBRAPA, C.Postal. 218, 70359-970, Brasilia, DF and A. K. Inoue and E. W. Kitajima, De-partamento de Biologia Celular, Universidade de Brasilia, 70919, Brasilia, DF, Brasil. Plant Dis. 79:82. Accepted for publication 15 September 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0082A.

In October 1992 a virus was isolated from two pea samples (Pisum sativum L.) cv. Torta de Flor Roxa (TFR) showing dark green mottling symptom in leaves collected in a commercial pea field of Brasilia, Brazil. In the area about 40% of the plants showed mosaic symptoms. Some plants were found to be infected by pen seedborne mosaic virus (PSbMV), indicating mixed infection. The unidentified virus isolate was maintained in pea cv. TFR in the greenhouse by mechanical inoculation. This virus was taken through three single lesion transfers in Chenopodium quinoa Willd. prior to use in other experiments. It was transmitted from pea to pea by Myzus persicae (Suizer) in a nonpersistent manner. Electron microscopy assays revealed typical potyvirus particles and pin-wheel inclusions, in purified virus samples and in ultrathin section, respectively. The host range of the virus did not match any potyviruses reported to infect pea. The virus systemically infected pea cvs. Alaska 81, resistant to pea seedborne mosaic virus, Triofin and TFR, hens culinaris Medik. cv. Precoz, Nicotiana benthamiana Domin., Zinnia elegans Jacq., Helianthus annuus Linn. cv. Sun Gold, Sesamum indicum L. Spinacia oleracea L. and Bidens pilosa L. It caused only local infection in Vicia faba L., Phaseolus vulgaris L. cv. Top Crop, Nicotiana tabacum L. cv Turkish NN, and N. rustica L.. The host responses were very close to those reported for Bidens mosaic virus (BiMV)(1). In Serological dot-blots, the virus strongly reacted with BiMV antiserum (1) raised against BiMV isolated Bidens pilosa L. and intermediately with potato virus Y. In double immunodifusion test, the virus showed homologous precipitation band with the BiMV antiserum. These results indicate that a BiMV was isolated from pea which is the first report of natural infection of pea by BiMV. The spread of the disease can now be determined as antisera to this virus is now available.