Viruses Causing Mosaic Diseases of Amaryllis in Japan

Abstract

A virus isolated from a mosaic plant of amaryllis (Hippeastrum hybridum) in Shizuoka is identified as Hippeastrum mosaic virus (HMV), because of its similarity to the description of HMV by Brants et al. (1965) in host range, physical properties, morphology, and lack of aphid transmission. Namely, the virus is readily transmitted by juice inoculation, but not by Myzus persicae. By mechanical inoculation, it produced systemic mosaic in amaryllis and Lilium formosanum, and local lesions in Chenopodium amaranticolor and Gomphrena globosa. New Zealand spinach, Raphanus sativus, bean (Chajiro and Otebo), cowpea (Kurodane), broadbean, Nicotiana glutinosa, N. tabacum (Bright Yellow), petunia and tomato were not susceptible. In electron microscopy using dip method, long flexuous thread-like particles were observed. Majority of the particles were 600∼800mμ in length, but there was no distinct mode. The virus in vitro withstood heating at 65°C for 10 minutes, dilution to 1:100 and 1 day's aging at 20°C.Twenty-three samples of mosaic plants of amaryllis obtained from Shizuoka, Fujinomiya and Tachikawa were tested for HMV and CMV on a series of differential hosts. All samples proved to include HMV, while about one third of them included also CMV simultaneously. The samples from which only HMV were isolated, showed mosaic symptoms having rather coarse dark green areas irregular in size and shape. CMV, isolated from amaryllis, revealed some differences from the ordinary strain of CMV in host range and in symptoms on tomato, potato, N. glutinosa, G. globosa, petunia, etc.