Characterization, Epidemiology and Management of Papaya ringspot virus

Papaya ringspot is a major viral disease of papaya caused by Papaya ringspot virus. Its spread to over 30 countries has threatened commercial cultivation and papaya based industries in the world. The disease map was prepared for the Karnataka state. The antiserum was produced by immunizing rabbit with purified virus and used for serodiagnosis of virus in papaya samples from farmer's fields. In histopathology, structural staining revealed reduction in size and loss of columnar shape of palisade cell and complete disintegration of spongy cells in diseased leaf. The reduction in polysaccharides and protein but increase in nucleic acid was observed in diseased plant. The number of fertile pollens was more in healthy flowers. There was reduction in size of fruits and papain content in diseased plants. Field trial on pesticides, anti-viral principles, viricides, oils and micronutrients indicated delayed disease appearance by boron spray. The meristem tip culture produced good callus in MS medium with 2,4-D and coconut water. The coat protein gene was amplified, cloned, sequenced and analyzed. This research work will benefit farmers, students, scientists and policy makers.