Sorghum, Pathologist, AICSIP, University of Agricultural Sciences, Dharwad-580005, Karnataka.
Abstracts of the papers presented at the 16th Annual Convention and International Symposium of Indian Virological Society on “Management of Vector-Borne Viruses” at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Hyderabad, India, February 7–10, 2006.
An isolate of Maize stripe virus (MSpV) is an important emerging disease infecting sorghum in Southern Peninsular India. The disease is characterized by the appearance of yellow stripes symptoms on the leaves, stunted plant growth, partial panicle exertion with poor seed set or no seeds. The disease incidence ranged from 10–20 per cent during post rainy season. In nature, the virus is transmitted persistently by a delphacid insect vector, Peregrinus maidis. The disease monitoring results indicated that, 71 per cent of the 276 samples from 33 locations in 11 districts of Karnataka reacted positive to MSpV in Penicillinase-based ELISA test. Of the 11 cultivated, 36 fodder and 15 weed species tested, only wheat (Tritium aestivum) and Johnson grass (Sorghum helepense) expressed characteristic stripe symptoms. The results also indicated that the Johnson grass and cropping patterns play a critical role in perpetuation of both virus and its transmitting vector over seasons/years. The results of field studies showed that the increase in disease incidence from 0.05 per cent at 30 days crop age to 4.10 percent at 105 days, where as decrease in vector populations as the age of the crop advances during the cropping season. The successive sorghum crop over seasons influenced the increase of both disease incidence (1.6 to 13.9%) and vector population (2.4 to 9.2/plant) respectively. An attempt to identify resistance sources virus disease using efficient screening methods and it was found that none of the five races (Bicolor, Kafir, Guinea, Cadautum and Durra) of sorghum found resistant to virus infection.
