First report of Dasheen mosaic virus infecting four ornamental aroids in India

Dasheen mosaic virus (DsMV) has been reported infecting aroids in a number of countries (Zettler & Hartman, 1995). In a survey of ornamental aroids grown in the Kangra Valley of Himachal Pradesh, India, four species showed virus like symptoms: Aglaonema sp. (mosaic), Philodendron sp. (mosaic, vein clearing and leaf malformation), Colocasia esculenta (mosaic and chlorotic feathering) and Zantedeschia sp. (mosaic and leaves malformation). Sap inoculations using epidermal strips from these infected plants induced chlorotic lesions on Chenopodium amaranticolor, C. quinoa, Nicotiana benthamiana and Saponaria vaccaria after 10 to 12 days and mosaic on Philodendron sp. Vein yellowing was also observed on some inoculated plants of C. quinoa and N. benthamiana. Amaranthus caudatus, Capsicum annuum, Cucumis sativus, Datura stramonium, Gomphrena globosa, N. clevelandii, N. glutinosa, N. rustica, N. tabacum cvs. White Burley and Samsun, Petunia hybrida, Phaseolus vulgaris and Zinnia elegans remained symptomless. Using the aphid species Myzus persicae, Aphis craccivora and A. gossypii, the virus was transmitted non-persistently to Philodendron sp., with infection confirmed by DAS-ELISA (Agdia, USA). From all four naturally-infected aroids and the mechanically infected Philodendron sp., a virus was purified as described earlier (Abo El-Nil et al., 1977). Using electron microscopy, filamentous particles (c. 750 x 11 nm) were observed both in the leaf epidermis of infected plants and in purified preparations. In ultrathin sections of the leaves, characteristic potyvirus-like cylindrical inclusions were observed. In double diffusion tests and DAS-ELISA the purified preparations reacted with DsMV-specific antibodies (Agdia, USA). These observations lead to the conclusion that the virus infecting these four aroids is DsMV. This is the first definitive report of DsMV infecting ornamental aroids in India.