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Etiology

Lettuce Infectious Yellows Virus--A New Type of Whitefly-Transmitted Virus. J. E. Duffus, Plant pathologist, USDA-ARS, U.S. Agricultural Research Station, 1636 E. Alisal St., Salinas, CA 93905; R. C. Larsen(2), and H. Y. Liu(3). (2)Graduate assistant, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; (3)Plant pathologist, USDA-ARS, U.S. Agricultural Research Station, 1636 E. Alisal St., Salinas, CA 93905. Phytopathology 76:97-100. Accepted for publication 8 August 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1986. DOI: 10.1094/Phyto-76-97.

A new yellowing disease of lettuce, sugarbeet, carrot, and other crop and weed hosts was found in the desert areas of southwestern United States. The inciting virus (lettuce infectious yellows virus [LIYV]) was transmitted by the sweet potato whitefly (Bemisia tabaci) in a semipersistent manner, but it was not mechanically transmissible. The virus was retained by viruliferous whiteflies for 3 days in serial transfers on susceptible hosts. LIYV had a wide host range (45 species in 15 plant families) and caused economically significant losses in a number of important crop plants. The virus was purified by differential centrifugation and density gradient centrifugation. Purified preparations had an A_{260 280nm} ratio of 1.28 and contained long flexuous particles 13-14 nm wide and 1,800-2,000 nm long. An antiserum with a homologous titer of 1/1,024 showed no relationship to beet pseudo-yellows virus and could be used to detect greenhouse- and field-infected plants by the ELISA method. The host range, particle size, insect transmission, and serology clearly distinguished LIYV from previously described viruses.