Naidu, R.Venugopal, M.N.2014-06-132014-06-132007-02-08In: Proceedings, PLACROSYM VI, RRII,Kottayam, 16-20 Dec. 1984. Edited by M. R. Sethuraj and others 1987 p-121-127http://hdl.handle.net/123456789/2905The incubation period of 'Katte' virus disease was studied by inoculating grown up clumps under field conditions over a period of three years. The disease incubation period varied from 20 to 114 days during different months of incubation. However, the number of leaves produced during the incubation period remain more or less constant. Symptom expression was directly influenced by the growth of plants as indicated by early expression in the active growing period (May to November) and late expression in dry period (December to April). Higher transmission of the virus was obtained when young growing parts were used as a source of inoculum as against low transmission with mature and old parts. The old leaf sheaths which are the natural breeding sites of the vector were found to be a poor inoculum source. The various forms of aphid found naturally colonising on the old drying parts may not play a significant role in disease spread.enArticle