1respectively, Plant Virus Research Station, Poona-5.
2Division of Mycology & Plant Pathology, Indian Agricultural Research Institute, New Delhi-12.
3Indian Institute of Horticultural Research, 255 Upper Palace Orchards, Bangalore-6.
Indian Agricultural Research Institute, Plant Virus Research Station, Poona-5.
A virus inducing tumorous growth in Mpsambi sweet orange [Citrus sinensis (L.) Osbeck] was collected in 1960 and designated “tumor decline virus” (TDV) of citrus. The virus is transmitted by dodder, Cuscuta chinensis Lamk., which acts as a differential vector transmitting only the TDV from a mixed infection of TDV and tristeza virus. TDV is the first citrus virus transmitted by C. chinensis, and is also transmitted by Toxoptera citricida (Kirk.), by pin-pricking through tumor tissue, and by tissue grafting. In systemically infected Kagzi lime [Citrus aurantifolia (Christem.) Swingle] pin-pricking readily induced formation of tumors. The virus could also infect Medicago sativa L., Rumex vesicarius L. and Duranta repens L. in addition to Kagzi lime, Key lime, rough lemon Citrus jambhiri Lushington) sweet orange and sour orange (Citrus aurantiumh.). Grapefruit (Citrus parodist Macf.) and Rangpur lime (Citrus limonia Osbeck) reacted poorly. No trace of any pathogenic organism was found in the tumor tissues. Observations on the disease suggest that the TDV is similar to vein-enatton virus and may be related to the woody gall virus.
