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Whitefly Transmission and Some Properties of Cowpea Mild Mottle Virus on Soybean in Thailand. M. Iwaki, Institute for Plant Virus Research, Tsukuba Science City, Yatabe, Ibaraki 305, Japan. P. Thongmeearkom and M. Prommin, Division of Plant Pathology and Microbiology, Department of Agriculture, Bangkhen, Bangkok 9, Thailand; and Y. Honda and T. Hibi, Institute for Plant Virus Research, Tsukuba Science City. Plant Dis. 66:365-368. Accepted for publication 7 July 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-365.

A rod-shaped virus was isolated from naturally infected soybean (Glycine max) plants collected at Phitsanulok, northern Thailand, in 1979. The virus caused mild mottle symptoms in soybean and was transmitted by whiteflies, Bemisia tabaci, in a semipersistent manner, by sap inoculation and through soybean seed; it was not transmitted by the aphids Aphis craccivora or A. glycines. Among 26 plant species tested by mechanical inoculation, the virus systemically infected mainly plants of the family Leguminosae, and it produced poorly defined local lesions on inoculated leaves of Chenopodium amaranticolor. Virus particle dimensions (1015 × 650700 nm) were in the range of those of carlaviruses. In tube precipitin tests, the virus reacted with antiserum to cowpea mild mottle virus, a previously reported virus infecting legumes in Africa, and showed distant serologic relationships with carnation latent virus and chrysanthemum virus B but not with other morphologically similar viruses. Infectivity of the virus was retained in sap diluted to 105 but not 106, heated for 10 min at 70 C but not 75 C, or held at 20 C for 21 days but not 28 days. The virus contained single-stranded ribonucleic acid and was identified as cowpea mild mottle virus on the basis of host range, symptomatology, particle morphology, and serologic relationships.