Two new virus isolates, passion fruit mosaic virus - Jalan Kebun (PFMV-K) and passion fruit mosaic virus - University of Malaya (PFMV-MU) were obtained from Passiflora laurifolia and P. edulis f.flavicarpa respectively. Sap inoculation studies showed that except for Cassia occidentalis, which was not susceptible to PFMV-MU, the host range for the trvo virus isolates were similar. However, there was a slight variation in symptoms expressed on the same indicator plant separately inoculated with the two virus isolates. The following plants were found to be susceptible to both the virus isolates: Chenopodium arnaratilicolor, Gomphrena globosa, P. edulis, P. edulis f.flavicarpa, P. maliformis, P. foetida, P. lingularis, P. mocrocorpa, P. mollisima, P. platyloba, and P. vitifolia. Plants which were found not susceptible when inoculated with the 2 virus isolates included: Cucumis sativus. Lathyrus odoratus, Phoseolus vulgaris, Vicia faba, Vigna sesquipedalis, V. sinensis, Plantago major, Capsicum annuum, Datura stramonium, Nicotiana glutinosa, N. tabacum, N. rustica, and N. xanthi. The thermal inactivation point for PFMV-K was between 67^o to 69^oC and that for PFMV-MU at 69^oC to 70^oC. Dilution-end-point of the two virus isolates were between 10^-1 to 1O^-2. PFMV-K remained infective for 2 days at 25^oC while PFMV-MU remained infective for 6 days at 25^oC. Apart from C. occidentalis, which could be used as a differential host for the 2 virus isolates, aphid vectors of the two viruses could also be used to differentiate between them. Myzus persicae (Sulz.) readily transmitted PFMV-K and PFMV-MU in a nonpersistent manner while Aphis craccivora Koch. and A. gossypii Glover. transmitted PFMV-MU non-persistently, but failed to transmit PFMV-K. Rhopalosiphum maidis Fitch and Toxoptera citricidus Kirk were not vectors of both virus isolates. Both PFMV-K and PFMV-MU were readily graft transmissible using the leaf-graft technique. Transmission tests with leaf-exudate of both virus isolates gave negative results. PFMV-K and PFMV-MU could be spread from diseased to healthy passion fruit vines during pruning operations.

 

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