Identification of Tomato Spotted Wilt-like Virus on Watermelon in Taiwan. Shyi- Dong Yeh, Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan. Ying-Chun Lin, Ying-Huei Cheng, Chung-Lung Jih, Moh-Jih Chen, and Ching-Chung Chen. Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan; and Taichung District Agricultural Improvement Station, Tatseun, Changhua County, Taiwan, Republic of China. Plant Dis. 76:835-840. Accepted for publication 6 February 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0835.

The causal agent of an unusual disease affecting watermelon (Citrullus lanatus) in Taiwan was identified as tomato spotted wilt-like virus in the tospovirus group on the basis of particle morphology, host reactions, serology, and transmission by thrips. Host symptoms included leaf crinkling, mottling, yellow spotting, short internodes, upright growth of younger branches, and tip necrosis. The systemic infection of cucurbits and transmissibility by the vector Thrips palmi distinguished this isolate from most other tomato spotted wilt virus (TSWV) isolates. Serological tests by enzyme-linked immunosorbent assay and western blotting with polyclonal and monoclonal antibodies demonstrated that the watermelon virus is serologically related to the TSWV that causes silver mottle on watermelon in Okinawa (Japan) and not to the tomato, lettuce, and amaryllis isolates of TSWV from other countries.