Transmission, Movement, and Inactivation of Cymbidium Mosaic and Odontoglossum Ringspot Viruses. I. S. HU, Department of Plant Pathology, University of Hawaii at Manoa, Honolulu 96822. S. FERREIRA, M. Q. XU, M. LU, M. 1HA, E. PFLUM, and M. WANG, Department of Plant Pathology, University of Hawaii at Manoa, Honolulu 96822. Plant Dis. 78:633-636. Accepted for publication 2 March 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0633.

Transmission and movement studies were conducted on orchids mechanically inoculated with cymbidium mosaic virus (CyMV) or odontoglossum ringspot virus (ORSV). Transmission of CyMV and ORSV to University of Hawaii (UH) Dendrobium hybrids was efficient; both viruses were detected in inoculated leaves a minimum of 3 days after inoculation. Cymbidium mosaic virus moved systemically from inoculated leaves to roots (minimum 10 days after inoculation) and then to other leaves (minimum 20 days after inoculation). Thirty-two of 33 CyMV-inoculated orchid plants were systemically infected. Systemic movement of ORSV took about 7 mo and occurred in only one of 38 inoculated orchid plants. Seven chemicals were evaluated for inactivation of CyMV on pruning tools for disease control. Skim milk was found to be effective, noncaustic, and inexpensive for the inactivation of CyMV inoculated on local lesion indicator host plants. However, when systemic host plants (orchids) were used in evaluation, skim milk and other chemicals were ineffective for inactivation of CyMV. A 1% concentration of NaOH inactivated both CyMV and ORSV, but 10 and 20% concentrations were phytotoxic.